Convert junit4 to junit5

Issue-ID: POLICY-5041
Change-Id: I6bad59c375dffdc87c31730057ce7b0543754545
Signed-off-by: adheli.tavares <adheli.tavares@est.tech>

93 files changed, 1801 insertions, 1786 deletions

diff --git a/context/context-management/src/main/java/org/onap/policy/apex/context/ContextAlbum.java b/context/context-management/src/main/java/org/onap/policy/apex/context/ContextAlbum.java
index 358b95327..f8ca251ba 100644
--- a/context/context-management/src/main/java/org/onap/policy/apex/context/ContextAlbum.java
+++ b/context/context-management/src/main/java/org/onap/policy/apex/context/ContextAlbum.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -84,7 +85,7 @@ public interface ContextAlbum extends Map<String, Object> {
     SchemaHelper getSchemaHelper();
 
     /**
-     * Place a read lock on a key in this album across the entire cluster.
+     * Place a read lock on a key on this album across the entire cluster.
      *
      * @param key The key to lock
      * @throws ContextException on locking errors
@@ -92,7 +93,7 @@ public interface ContextAlbum extends Map<String, Object> {
     void lockForReading(String key) throws ContextException;
 
     /**
-     * Place a write lock on a key in this album across the entire cluster.
+     * Place a write lock on a key on this album across the entire cluster.
      *
      * @param key The key to lock
      * @throws ContextException on locking errors
@@ -100,7 +101,7 @@ public interface ContextAlbum extends Map<String, Object> {
     void lockForWriting(String key) throws ContextException;
 
     /**
-     * Release the the read lock on a key in this album across the entire cluster.
+     * Release the read lock on a key on this album across the entire cluster.
      *
      * @param key The key to unlock
      * @throws ContextException on locking errors
@@ -108,7 +109,7 @@ public interface ContextAlbum extends Map<String, Object> {
     void unlockForReading(String key) throws ContextException;
 
     /**
-     * Release the the write lock on a key in this album across the entire cluster.
+     * Release the write lock on a key on this album across the entire cluster.
      *
      * @param key The key to unlock
      * @throws ContextException on locking errors
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/ContextExceptionTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/ContextExceptionTest.java
index ff07b1e50..19f695cda 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/ContextExceptionTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/ContextExceptionTest.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,25 +21,25 @@
 
 package org.onap.policy.apex.context;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-public class ContextExceptionTest {
+class ContextExceptionTest {
 
     @Test
-    public void testContextException() {
+    void testContextException() {
         assertEquals("context exception message", new ContextException("context exception message").getMessage());
         assertEquals("context exception message",
-                new ContextException("context exception message", new IOException()).getMessage());
+            new ContextException("context exception message", new IOException()).getMessage());
     }
 
     @Test
-    public void testContextRuntimeException() {
+    void testContextRuntimeException() {
         assertEquals("context exception message",
-                new ContextRuntimeException("context exception message").getMessage());
+            new ContextRuntimeException("context exception message").getMessage());
         assertEquals("context exception message",
-                new ContextRuntimeException("context exception message", new IOException()).getMessage());
+            new ContextRuntimeException("context exception message", new IOException()).getMessage());
     }
 }
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/ContextAlbumImplTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/ContextAlbumImplTest.java
index 6ebb79f43..216e3686a 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/ContextAlbumImplTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/ContextAlbumImplTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,15 +22,17 @@
 package org.onap.policy.apex.context.impl;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.context.ContextAlbum;
 import org.onap.policy.apex.context.ContextException;
 import org.onap.policy.apex.context.Distributor;
@@ -49,11 +51,11 @@ import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
 import org.onap.policy.common.parameters.ParameterService;
 
-public class ContextAlbumImplTest {
+class ContextAlbumImplTest {
     /**
-     * Set ups everything for the test.
+     * Set-ups everything for the test.
      */
-    @BeforeClass
+    @BeforeAll
     public static void prepareForTest() {
         final ContextParameters contextParameters = new ContextParameters();
         contextParameters.getLockManagerParameters()
@@ -79,7 +81,7 @@ public class ContextAlbumImplTest {
     /**
      * Clear down the test data.
      */
-    @AfterClass
+    @AfterAll
     public static void cleanUpAfterTest() {
         ParameterService.deregister(ContextParameterConstants.DISTRIBUTOR_GROUP_NAME);
         ParameterService.deregister(ContextParameterConstants.LOCKING_GROUP_NAME);
@@ -90,7 +92,7 @@ public class ContextAlbumImplTest {
     }
 
     @Test
-    public void testNullsOnConstructor() {
+    void testNullsOnConstructor() {
         assertThatThrownBy(() -> new ContextAlbumImpl(null, null, null))
             .hasMessage("Context album definition may not be null");
 
@@ -101,13 +103,13 @@ public class ContextAlbumImplTest {
             .hasMessage("Album map may not be null");
 
         assertThatThrownBy(() -> new ContextAlbumImpl(new AxContextAlbum(), new JvmLocalDistributor(),
-            new LinkedHashMap<String, Object>()))
-                .hasMessage("Model for org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas "
-                    + "not found in model service");
+            new LinkedHashMap<>()))
+            .hasMessage("Model for org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas "
+                + "not found in model service");
     }
 
     @Test
-    public void testAlbumInterface() throws ContextException {
+    void testAlbumInterface() throws ContextException {
         AxContextSchemas schemas = new AxContextSchemas();
         AxContextSchema simpleStringSchema = new AxContextSchema(new AxArtifactKey("SimpleStringSchema", "0.0.1"),
             "JAVA", "java.lang.String");
@@ -118,39 +120,25 @@ public class ContextAlbumImplTest {
             true, AxArtifactKey.getNullKey());
 
         assertThatThrownBy(
-            () -> new ContextAlbumImpl(axContextAlbum, new JvmLocalDistributor(), new LinkedHashMap<String, Object>()))
-                .hasMessageContaining("could not initiate schema management for context album AxContextAlbum");
+            () -> new ContextAlbumImpl(axContextAlbum, new JvmLocalDistributor(), new LinkedHashMap<>()))
+            .hasMessageContaining("could not initiate schema management for context album AxContextAlbum");
 
         axContextAlbum.setItemSchema(simpleStringSchema.getKey());
         Distributor distributor = new JvmLocalDistributor();
         distributor.init(axContextAlbum.getKey());
-        ContextAlbum album = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<String, Object>());
+        ContextAlbum album = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<>());
 
-        assertEquals("TestContextAlbum", album.getName());
-        assertEquals("TestContextAlbum:0.0.1", album.getKey().getId());
-        assertEquals("TestContextAlbum:0.0.1", album.getAlbumDefinition().getId());
-        assertEquals("SimpleStringSchema:0.0.1", album.getSchemaHelper().getSchema().getId());
+        assertGetValuesFromContextAlbum(album);
 
         assertThatThrownBy(() -> album.containsKey(null))
             .hasMessage("null values are illegal on method parameter \"key\"");
-        assertEquals(false, album.containsKey("Key0"));
-
-        assertThatThrownBy(() -> album.containsValue(null))
-            .hasMessage("null values are illegal on method parameter \"value\"");
-        assertEquals(false, album.containsValue("some value"));
-
-        assertThatThrownBy(() -> album.get(null))
-            .hasMessage("album \"TestContextAlbum:0.0.1\" null keys are illegal on keys for get()");
+        assertFalse(album.containsKey("Key0"));
 
-        assertThatThrownBy(() -> album.put(null, null))
-            .hasMessage("album \"TestContextAlbum:0.0.1\" null keys are illegal on keys for put()");
-
-        assertThatThrownBy(() -> album.put("KeyNull", null))
-            .hasMessage("album \"TestContextAlbum:0.0.1\" null values are illegal on key \"KeyNull\"" + " for put()");
+        assertUsingNullValues_RaiseExceptions(album);
 
         AxContextAlbum axContextAlbumRo = new AxContextAlbum(new AxArtifactKey("TestContextAlbum", "0.0.1"), "Policy",
             false, simpleStringSchema.getKey());
-        ContextAlbum albumRo = new ContextAlbumImpl(axContextAlbumRo, distributor, new LinkedHashMap<String, Object>());
+        ContextAlbum albumRo = new ContextAlbumImpl(axContextAlbumRo, distributor, new LinkedHashMap<>());
 
         assertThatThrownBy(() -> albumRo.put("KeyReadOnly", "A value for a Read Only Album"))
             .hasMessage("album \"TestContextAlbum:0.0.1\" put() not allowed on read only albums "
@@ -173,52 +161,25 @@ public class ContextAlbumImplTest {
         assertThatThrownBy(albumRo::clear)
             .hasMessage("album \"TestContextAlbum:0.0.1\" clear() not allowed on read only albums");
 
-        // The following locking tests pass because the locking protects access to Key0
-        // across all
-        // copies of the distributed album whether the key exists or not
-        album.lockForReading("Key0");
-        assertEquals(null, album.get("Key0"));
-        album.unlockForReading("Key0");
-        assertEquals(null, album.get("Key0"));
-
-        album.lockForWriting("Key0");
-        assertEquals(null, album.get("Key0"));
-        album.unlockForWriting("Key0");
-        assertEquals(null, album.get("Key0"));
-
-        // Test write access, trivial test because Integration Test does
-        // a full test of access locking over albums in different JVMs
-        album.lockForWriting("Key0");
-        assertEquals(null, album.get("Key0"));
-        album.put("Key0", "value of Key0");
-        assertEquals("value of Key0", album.get("Key0"));
-        album.unlockForWriting("Key0");
-        assertEquals("value of Key0", album.get("Key0"));
-
-        // Test read access, trivial test because Integration Test does
-        // a full test of access locking over albums in different JVMs
-        album.lockForReading("Key0");
-        assertEquals("value of Key0", album.get("Key0"));
-        album.unlockForReading("Key0");
+        assertLockingUnlocking(album);
 
         AxArtifactKey somePolicyKey = new AxArtifactKey("MyPolicy", "0.0.1");
         AxReferenceKey somePolicyState = new AxReferenceKey(somePolicyKey, "SomeState");
 
-        AxConcept[] userArtifactStack = { somePolicyKey, somePolicyState };
+        AxConcept[] userArtifactStack = {somePolicyKey, somePolicyState};
         album.setUserArtifactStack(userArtifactStack);
         assertEquals("MyPolicy:0.0.1", album.getUserArtifactStack()[0].getId());
         assertEquals("MyPolicy:0.0.1:NULL:SomeState", album.getUserArtifactStack()[1].getId());
 
-        assertEquals(true, album.keySet().contains("Key0"));
-        assertEquals(true, album.values().contains("value of Key0"));
+        assertTrue(album.containsKey("Key0"));
+        assertTrue(album.containsValue("value of Key0"));
         assertEquals(1, album.entrySet().size());
 
         // The flush() operation fails because the distributor is not initialized with
-        // the album which
-        // is fine for unit test
+        // the album which is fine for unit test
         assertThatThrownBy(album::flush).hasMessage("map flush failed, supplied map is null");
         assertEquals(1, album.size());
-        assertEquals(false, album.isEmpty());
+        assertFalse(album.isEmpty());
 
         album.put("Key0", "New value of Key0");
         assertEquals("New value of Key0", album.get("Key0"));
@@ -231,13 +192,64 @@ public class ContextAlbumImplTest {
         assertEquals("New value of Key0", album.remove("Key0"));
 
         album.clear();
-        assertTrue(album.isEmpty());
 
         ModelService.clear();
     }
 
+    private static void assertUsingNullValues_RaiseExceptions(ContextAlbum album) {
+        assertThatThrownBy(() -> album.containsValue(null))
+            .hasMessage("null values are illegal on method parameter \"value\"");
+        assertFalse(album.containsValue("some value"));
+
+        assertThatThrownBy(() -> album.get(null))
+            .hasMessage("album \"TestContextAlbum:0.0.1\" null keys are illegal on keys for get()");
+
+        assertThatThrownBy(() -> album.put(null, null))
+            .hasMessage("album \"TestContextAlbum:0.0.1\" null keys are illegal on keys for put()");
+
+        assertThatThrownBy(() -> album.put("KeyNull", null))
+            .hasMessage("album \"TestContextAlbum:0.0.1\" null values are illegal on key \"KeyNull\"" + " for put()");
+    }
+
+    private static void assertGetValuesFromContextAlbum(ContextAlbum album) {
+        assertEquals("TestContextAlbum", album.getName());
+        assertEquals("TestContextAlbum:0.0.1", album.getKey().getId());
+        assertEquals("TestContextAlbum:0.0.1", album.getAlbumDefinition().getId());
+        assertEquals("SimpleStringSchema:0.0.1", album.getSchemaHelper().getSchema().getId());
+    }
+
+    private static void assertLockingUnlocking(ContextAlbum album) throws ContextException {
+        // The following locking tests pass because the locking protects access to Key0
+        // across all
+        // copies of the distributed album whether the key exists or not
+        album.lockForReading("Key0");
+        assertNull(album.get("Key0"));
+        album.unlockForReading("Key0");
+        assertNull(album.get("Key0"));
+
+        album.lockForWriting("Key0");
+        assertNull(album.get("Key0"));
+        album.unlockForWriting("Key0");
+        assertNull(album.get("Key0"));
+
+        // Test write access, trivial test because Integration Test does
+        // a full test of access locking over albums in different JVMs
+        album.lockForWriting("Key0");
+        assertNull(album.get("Key0"));
+        album.put("Key0", "value of Key0");
+        assertEquals("value of Key0", album.get("Key0"));
+        album.unlockForWriting("Key0");
+        assertEquals("value of Key0", album.get("Key0"));
+
+        // Test read access, trivial test because Integration Test does
+        // a full test of access locking over albums in different JVMs
+        album.lockForReading("Key0");
+        assertEquals("value of Key0", album.get("Key0"));
+        album.unlockForReading("Key0");
+    }
+
     @Test
-    public void testCompareToEqualsHash() throws ContextException {
+    void testCompareToEqualsHash() throws ContextException {
         AxContextSchemas schemas = new AxContextSchemas();
         AxContextSchema simpleIntSchema = new AxContextSchema(new AxArtifactKey("SimpleIntSchema", "0.0.1"), "JAVA",
             "java.lang.Integer");
@@ -253,26 +265,22 @@ public class ContextAlbumImplTest {
         axContextAlbum.setItemSchema(simpleIntSchema.getKey());
         Distributor distributor = new JvmLocalDistributor();
         distributor.init(axContextAlbum.getKey());
-        ContextAlbumImpl album = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<String, Object>());
+        ContextAlbumImpl album = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<>());
 
         assertNotEquals(0, album.hashCode());
 
-        assertEquals(0, album.compareTo(album));
         assertEquals(1, album.compareTo(null));
 
-        assertEquals(album, album);
         assertNotEquals(album, new DummyContextAlbumImpl());
 
-        ContextAlbumImpl otherAlbum = new ContextAlbumImpl(axContextAlbum, distributor,
-            new LinkedHashMap<String, Object>());
+        ContextAlbumImpl otherAlbum = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<>());
         assertEquals(album, otherAlbum);
 
         otherAlbum.put("Key", 123);
         assertNotEquals(album, otherAlbum);
 
         assertThatThrownBy(() -> {
-            ContextAlbumImpl otherAlbumBad = new ContextAlbumImpl(axContextAlbum, distributor,
-                new LinkedHashMap<String, Object>());
+            ContextAlbumImpl otherAlbumBad = new ContextAlbumImpl(axContextAlbum, distributor, new LinkedHashMap<>());
             otherAlbumBad.put("Key", "BadValue");
         }).hasMessage("Failed to set context value for key \"Key\" in album \"TestContextAlbum:0.0.1\": "
             + "TestContextAlbum:0.0.1: object \"BadValue\" of class \"java.lang.String\" "
@@ -281,7 +289,7 @@ public class ContextAlbumImplTest {
             "Policy", true, AxArtifactKey.getNullKey());
 
         otherAxContextAlbum.setItemSchema(simpleStringSchema.getKey());
-        otherAlbum = new ContextAlbumImpl(otherAxContextAlbum, distributor, new LinkedHashMap<String, Object>());
+        otherAlbum = new ContextAlbumImpl(otherAxContextAlbum, distributor, new LinkedHashMap<>());
         assertNotEquals(album, otherAlbum);
 
         assertThatThrownBy(album::flush).hasMessage("map flush failed, supplied map is null");
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/DummyContextAlbumImpl.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/DummyContextAlbumImpl.java
index 20398eb1a..6f7cd9fcb 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/DummyContextAlbumImpl.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/DummyContextAlbumImpl.java
@@ -1,19 +1,20 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
@@ -33,7 +34,6 @@ import org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum;
 
 /**
  * Dummy album implementation class.
- *
  */
 public class DummyContextAlbumImpl implements ContextAlbum {
 
@@ -42,7 +42,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public void clear() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -50,7 +50,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public boolean containsKey(Object key) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -58,7 +58,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public boolean containsValue(Object value) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -66,7 +66,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Set<Entry<String, Object>> entrySet() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -74,7 +74,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Object get(Object key) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -82,7 +82,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public boolean isEmpty() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -90,7 +90,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Set<String> keySet() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -98,7 +98,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Object put(String key, Object value) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -106,8 +106,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public void putAll(Map<? extends String, ? extends Object> map) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -115,7 +114,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Object remove(Object key) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -123,7 +122,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public int size() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -131,7 +130,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public Collection<Object> values() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -139,7 +138,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public AxArtifactKey getKey() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -147,7 +146,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public String getName() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -155,7 +154,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public AxContextAlbum getAlbumDefinition() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -163,43 +162,39 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public SchemaHelper getSchemaHelper() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
      * {@inheritDoc}.
      */
     @Override
-    public void lockForReading(String key) throws ContextException {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+    public void lockForReading(String key) {
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
      * {@inheritDoc}.
      */
     @Override
-    public void lockForWriting(String key) throws ContextException {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+    public void lockForWriting(String key) {
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
      * {@inheritDoc}.
      */
     @Override
-    public void unlockForReading(String key) throws ContextException {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+    public void unlockForReading(String key) {
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
      * {@inheritDoc}.
      */
     @Override
-    public void unlockForWriting(String key) throws ContextException {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+    public void unlockForWriting(String key) {
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -207,7 +202,7 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public AxConcept[] getUserArtifactStack() {
-        throw new NotImplementedException("Not Implemeted on dummy class");
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
@@ -215,17 +210,15 @@ public class DummyContextAlbumImpl implements ContextAlbum {
      */
     @Override
     public void setUserArtifactStack(AxConcept[] userArtifactStack) {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
     /**
      * {@inheritDoc}.
      */
     @Override
-    public void flush() throws ContextException {
-        throw new NotImplementedException("Not Implemeted on dummy class");
-
+    public void flush() {
+        throw new NotImplementedException("Not Implemented on dummy class");
     }
 
 }
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/SchemaHelperFactoryTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/SchemaHelperFactoryTest.java
index 663424411..501b76c0a 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/SchemaHelperFactoryTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/SchemaHelperFactoryTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,11 +22,11 @@
 package org.onap.policy.apex.context.impl.schema;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.context.impl.schema.java.JavaSchemaHelperParameters;
 import org.onap.policy.apex.context.parameters.ContextParameterConstants;
 import org.onap.policy.apex.context.parameters.SchemaParameters;
@@ -36,16 +36,16 @@ import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
 import org.onap.policy.common.parameters.ParameterService;
 
-public class SchemaHelperFactoryTest {
+class SchemaHelperFactoryTest {
     private static AxContextSchema intSchema;
     private static AxContextSchemas schemas;
     private static AxContextSchema badSchema;
 
     /**
-     * Set ups schema for the test.
+     * Set-ups schema for the test.
      */
-    @BeforeClass
-    public static void setupSchema() {
+    @BeforeAll
+    static void setupSchema() {
         schemas = new AxContextSchemas(new AxArtifactKey("AvroSchemas", "0.0.1"));
         ModelService.registerModel(AxContextSchemas.class, schemas);
 
@@ -53,13 +53,13 @@ public class SchemaHelperFactoryTest {
         badSchema = new AxContextSchema(new AxArtifactKey("IntSchema", "0.0.1"), "JAVA", "java.lang.Bad");
     }
 
-    @AfterClass
-    public static void clearParameters() {
+    @AfterAll
+    static void clearParameters() {
         ParameterService.clear();
     }
 
     @Test
-    public void testSchemaHelperFactory() {
+    void testSchemaHelperFactory() {
         assertThatThrownBy(() -> new SchemaHelperFactory().createSchemaHelper(null, null))
             .hasMessage("Parameter \"owningEntityKey\" may not be null");
         AxArtifactKey ownerKey = new AxArtifactKey("Owner", "0.0.1");
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperInstanceCreationTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperInstanceCreationTest.java
index 620a78152..f4c8c3e2d 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperInstanceCreationTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperInstanceCreationTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,11 +22,11 @@
 package org.onap.policy.apex.context.impl.schema.java;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.AfterClass;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.context.SchemaHelper;
 import org.onap.policy.apex.context.impl.schema.SchemaHelperFactory;
 import org.onap.policy.apex.context.parameters.ContextParameterConstants;
@@ -40,17 +40,17 @@ import org.onap.policy.common.parameters.ParameterService;
 
 /**
  * JavaSchemaHelperInstanceCreationTest.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
- * @version
  */
-public class JavaSchemaHelperInstanceCreationTest {
+class JavaSchemaHelperInstanceCreationTest {
     private final AxKey testKey = new AxArtifactKey("AvroTest", "0.0.1");
     private AxContextSchemas schemas;
 
     /**
-     * Set ups everything for the test.
+     * Set-ups everything for the test.
      */
-    @Before
+    @BeforeEach
     public void initTest() {
         schemas = new AxContextSchemas(new AxArtifactKey("AvroSchemas", "0.0.1"));
         ModelService.registerModel(AxContextSchemas.class, schemas);
@@ -62,40 +62,40 @@ public class JavaSchemaHelperInstanceCreationTest {
         ParameterService.register(schemaParameters);
     }
 
-    @AfterClass
+    @AfterAll
     public static void cleanUpAfterTest() {
         ParameterService.clear();
     }
 
 
     @Test
-    public void testNullEncoding() {
+    void testNullEncoding() {
         final AxContextSchema javaBooleanSchema =
-                new AxContextSchema(new AxArtifactKey("Boolean", "0.0.1"), "Java", "java.lang.Boolean");
+            new AxContextSchema(new AxArtifactKey("Boolean", "0.0.1"), "Java", "java.lang.Boolean");
         final AxContextSchema javaLongSchema =
-                new AxContextSchema(new AxArtifactKey("Long", "0.0.1"), "Java", "java.lang.Long");
+            new AxContextSchema(new AxArtifactKey("Long", "0.0.1"), "Java", "java.lang.Long");
         final AxContextSchema javaStringSchema =
-                new AxContextSchema(new AxArtifactKey("String", "0.0.1"), "Java", "java.lang.String");
+            new AxContextSchema(new AxArtifactKey("String", "0.0.1"), "Java", "java.lang.String");
 
         schemas.getSchemasMap().put(javaBooleanSchema.getKey(), javaBooleanSchema);
         schemas.getSchemasMap().put(javaLongSchema.getKey(), javaLongSchema);
         schemas.getSchemasMap().put(javaStringSchema.getKey(), javaStringSchema);
 
         final SchemaHelper schemaHelper0 =
-                new SchemaHelperFactory().createSchemaHelper(testKey, javaBooleanSchema.getKey());
+            new SchemaHelperFactory().createSchemaHelper(testKey, javaBooleanSchema.getKey());
         final SchemaHelper schemaHelper1 =
-                new SchemaHelperFactory().createSchemaHelper(testKey, javaLongSchema.getKey());
+            new SchemaHelperFactory().createSchemaHelper(testKey, javaLongSchema.getKey());
         final SchemaHelper schemaHelper2 =
-                new SchemaHelperFactory().createSchemaHelper(testKey, javaStringSchema.getKey());
+            new SchemaHelperFactory().createSchemaHelper(testKey, javaStringSchema.getKey());
 
         assertThatThrownBy(schemaHelper0::createNewInstance)
             .hasMessage("AvroTest:0.0.1: could not create an instance of class \"java.lang.Boolean\""
-                    + " using the default constructor \"Boolean()\"");
+                + " using the default constructor \"Boolean()\"");
         assertEquals(true, schemaHelper0.createNewInstance("true"));
 
         assertThatThrownBy(schemaHelper1::createNewInstance)
             .hasMessage("AvroTest:0.0.1: could not create an instance of class \"java.lang.Long\""
-                    + " using the default constructor \"Long()\"");
+                + " using the default constructor \"Long()\"");
         assertEquals(65536L, schemaHelper1.createNewInstance("65536"));
 
         assertEquals("", schemaHelper2.createNewInstance());
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperParametersTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperParametersTest.java
index 65b2ed6ff..418149e50 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperParametersTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperParametersTest.java
@@ -2,6 +2,7 @@
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ *  Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,26 +22,26 @@
 
 package org.onap.policy.apex.context.impl.schema.java;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.LinkedHashMap;
 import java.util.Map;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test Java schema helper parameters.
  */
-public class JavaSchemaHelperParametersTest {
+class JavaSchemaHelperParametersTest {
 
     @Test
-    public void testJavaSchemaHelperParameters() {
+    void testJavaSchemaHelperParameters() {
         JavaSchemaHelperParameters pars = new JavaSchemaHelperParameters();
 
         assertEquals("org.onap.policy.apex.context.impl.schema.java.JavaSchemaHelper",
-                        pars.getSchemaHelperPluginClass());
+            pars.getSchemaHelperPluginClass());
 
         assertEquals(0, pars.getJsonAdapters().size());
 
@@ -84,7 +85,7 @@ public class JavaSchemaHelperParametersTest {
     }
 
     @Test
-    public void testJavaSchemaHelperJsonAdapterParameters() {
+    void testJavaSchemaHelperJsonAdapterParameters() {
         JavaSchemaHelperJsonAdapterParameters pars = new JavaSchemaHelperJsonAdapterParameters();
 
         assertNull(pars.getName());
diff --git a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperTest.java b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperTest.java
index d06ac7469..773b6d84c 100644
--- a/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperTest.java
+++ b/context/context-management/src/test/java/org/onap/policy/apex/context/impl/schema/java/JavaSchemaHelperTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,16 +22,17 @@
 package org.onap.policy.apex.context.impl.schema.java;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import com.google.gson.JsonElement;
 import com.google.gson.JsonParser;
 import com.google.gson.JsonPrimitive;
 import java.math.BigDecimal;
 import java.time.Instant;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.context.SchemaHelper;
 import org.onap.policy.apex.context.parameters.ContextParameterConstants;
 import org.onap.policy.apex.context.parameters.SchemaParameters;
@@ -39,11 +40,11 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
 import org.onap.policy.common.parameters.ParameterService;
 
-public class JavaSchemaHelperTest {
+class JavaSchemaHelperTest {
     /**
      * Initialize JSON adapters.
      */
-    @BeforeClass
+    @BeforeAll
     public static void registerParameters() {
         JavaSchemaHelperParameters javaSchemaHelperPars = new JavaSchemaHelperParameters();
 
@@ -59,13 +60,13 @@ public class JavaSchemaHelperTest {
         ParameterService.register(schemaPars);
     }
 
-    @AfterClass
+    @AfterAll
     public static void deregisterParameters() {
         ParameterService.clear();
     }
 
     @Test
-    public void testJavaSchemaHelperInit() {
+    void testJavaSchemaHelperInit() {
         AxArtifactKey schemaKey = new AxArtifactKey("SchemaKey", "0.0.1");
         AxArtifactKey userKey = new AxArtifactKey("UserKey", "0.0.1");
 
@@ -73,23 +74,23 @@ public class JavaSchemaHelperTest {
 
         assertThatThrownBy(() -> new JavaSchemaHelper().init(userKey, badJavaTypeSchema))
             .hasMessage("UserKey:0.0.1: class/type java.lang.Rubbish for context schema"
-                    + " \"SchemaKey:0.0.1\" not found. Check the class path of the JVM");
+                + " \"SchemaKey:0.0.1\" not found. Check the class path of the JVM");
         AxContextSchema builtInJavaTypeSchema = new AxContextSchema(schemaKey, "Java", "short");
 
         assertThatThrownBy(() -> new JavaSchemaHelper().init(userKey, builtInJavaTypeSchema))
             .hasMessage("UserKey:0.0.1: class/type short for context schema "
-                    + "\"SchemaKey:0.0.1\" not found. Primitive types are not supported."
-                    + " Use the appropriate Java boxing type instead.");
+                + "\"SchemaKey:0.0.1\" not found. Primitive types are not supported."
+                + " Use the appropriate Java boxing type instead.");
     }
 
     @Test
-    public void testJavaSchemaHelperMethods() {
+    void testJavaSchemaHelperMethods() {
         SchemaHelper intSchemaHelper = new JavaSchemaHelper();
 
         assertEquals(AxArtifactKey.getNullKey(), intSchemaHelper.getUserKey());
-        assertEquals(null, intSchemaHelper.getSchema());
-        assertEquals(null, intSchemaHelper.getSchemaClass());
-        assertEquals(null, intSchemaHelper.getSchemaObject());
+        assertNull(intSchemaHelper.getSchema());
+        assertNull(intSchemaHelper.getSchemaClass());
+        assertNull(intSchemaHelper.getSchemaObject());
 
         assertThatThrownBy(intSchemaHelper::createNewInstance)
             .hasMessage("NULL:0.0.0: could not create an instance, schema class for the schema is null");
@@ -105,27 +106,27 @@ public class JavaSchemaHelperTest {
         assertEquals(userKey, intSchemaHelper.getUserKey());
         assertEquals(intSchema, intSchemaHelper.getSchema());
         assertEquals(Integer.class, intSchemaHelper.getSchemaClass());
-        assertEquals(null, intSchemaHelper.getSchemaObject());
+        assertNull(intSchemaHelper.getSchemaObject());
 
         assertThatThrownBy(intSchemaHelper::createNewInstance)
             .hasMessage("UserKey:0.0.1: could not create an instance of class "
-                    + "\"java.lang.Integer\" using the default constructor \"Integer()\"");
+                + "\"java.lang.Integer\" using the default constructor \"Integer()\"");
         assertThatThrownBy(() -> intSchemaHelper.createNewInstance(Float.parseFloat("1.23")))
             .hasMessage("UserKey:0.0.1: the object \"1.23\" of type "
-                    + "\"java.lang.Float\" is not an instance of JsonObject and is not "
-                    + "assignable to \"java.lang.Integer\"");
+                + "\"java.lang.Float\" is not an instance of JsonObject and is not "
+                + "assignable to \"java.lang.Integer\"");
         assertThatThrownBy(() -> intSchemaHelper.createNewInstance("hello"))
             .hasMessage("UserKey:0.0.1: could not create an instance of class \"java.lang.Integer\" "
-                    + "using the string constructor \"Integer(String)\"");
+                + "using the string constructor \"Integer(String)\"");
         JsonElement jsonIntElement = null;
-        assertEquals(null, intSchemaHelper.createNewInstance(jsonIntElement));
+        assertNull(intSchemaHelper.createNewInstance(jsonIntElement));
 
         jsonIntElement = JsonParser.parseString("123");
 
         assertEquals(123, intSchemaHelper.createNewInstance(jsonIntElement));
         assertEquals(123, intSchemaHelper.createNewInstance(Integer.parseInt("123")));
 
-        assertEquals(null, intSchemaHelper.unmarshal(null));
+        assertNull(intSchemaHelper.unmarshal(null));
         assertEquals(123, intSchemaHelper.unmarshal(Integer.parseInt("123")));
         assertEquals(123, intSchemaHelper.unmarshal(Byte.parseByte("123")));
         assertEquals(123, intSchemaHelper.unmarshal(Short.parseShort("123")));
@@ -135,7 +136,7 @@ public class JavaSchemaHelperTest {
     }
 
     @Test
-    public void testJavaSchemaHelperUnmarshal() {
+    void testJavaSchemaHelperUnmarshal() {
         AxArtifactKey schemaKey = new AxArtifactKey("SchemaKey", "0.0.1");
         AxArtifactKey userKey = new AxArtifactKey("UserKey", "0.0.1");
 
@@ -167,44 +168,53 @@ public class JavaSchemaHelperTest {
         stringSchemaHelper.init(userKey, stringSchema);
 
         AxContextSchema myBaseClassSchema = new AxContextSchema(schemaKey, "Java",
-                "org.onap.policy.apex.context.impl.schema.java.SupportBaseClass");
+            "org.onap.policy.apex.context.impl.schema.java.SupportBaseClass");
         SchemaHelper myBaseClassSchemaHelper = new JavaSchemaHelper();
         myBaseClassSchemaHelper.init(userKey, myBaseClassSchema);
 
-        assertEquals(null, byteSchemaHelper.unmarshal(null));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal("123"));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Integer.parseInt("123")));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Byte.parseByte("123")));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Short.parseShort("123")));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Long.parseLong("123")));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Float.parseFloat("123")));
-        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Double.parseDouble("123")));
-        assertThatThrownBy(() -> byteSchemaHelper.unmarshal("one two three"))
-            .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Byte\"");
-        assertEquals(null, shortSchemaHelper.unmarshal(null));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal("123"));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Integer.parseInt("123")));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Byte.parseByte("123")));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Short.parseShort("123")));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Long.parseLong("123")));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Float.parseFloat("123")));
-        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Double.parseDouble("123")));
-        assertThatThrownBy(() -> shortSchemaHelper.unmarshal("one two three"))
+        assertByteUnmarshal(byteSchemaHelper);
+        assertShortUnmarshal(shortSchemaHelper);
+        assertIntUnmarshal(intSchemaHelper);
+        assertLongUnmarshal(longSchemaHelper);
+        assertFloatUnmarshal(floatSchemaHelper);
+        assertDoubleUnmarshal(doubleSchemaHelper);
+        assertEquals("123", stringSchemaHelper.unmarshal(123));
+
+        SupportSubClass subClassInstance = new SupportSubClass("123");
+        assertEquals(subClassInstance, myBaseClassSchemaHelper.unmarshal(subClassInstance));
+    }
+
+    private static void assertDoubleUnmarshal(SchemaHelper doubleSchemaHelper) {
+        assertNull(doubleSchemaHelper.unmarshal(null));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal("123"));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Integer.parseInt("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Byte.parseByte("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Short.parseShort("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Long.parseLong("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Float.parseFloat("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Double.parseDouble("123")));
+        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(BigDecimal.valueOf(123)));
+        assertThatThrownBy(() -> doubleSchemaHelper.unmarshal("one two three"))
             .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Short\"");
-        assertEquals(null, intSchemaHelper.unmarshal(null));
-        assertEquals(123, intSchemaHelper.unmarshal("123"));
-        assertEquals(123, intSchemaHelper.unmarshal(Integer.parseInt("123")));
-        assertEquals(123, intSchemaHelper.unmarshal(Byte.parseByte("123")));
-        assertEquals(123, intSchemaHelper.unmarshal(Short.parseShort("123")));
-        assertEquals(123, intSchemaHelper.unmarshal(Long.parseLong("123")));
-        assertEquals(123, intSchemaHelper.unmarshal(Float.parseFloat("123")));
-        assertEquals(123, intSchemaHelper.unmarshal(Double.parseDouble("123")));
-        assertThatThrownBy(() -> intSchemaHelper.unmarshal("one two three"))
+                + "compatible with class \"java.lang.Double\"");
+    }
+
+    private static void assertFloatUnmarshal(SchemaHelper floatSchemaHelper) {
+        assertNull(floatSchemaHelper.unmarshal(null));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal("123"));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Integer.parseInt("123")));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Byte.parseByte("123")));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Short.parseShort("123")));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Long.parseLong("123")));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Float.parseFloat("123")));
+        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Double.parseDouble("123")));
+        assertThatThrownBy(() -> floatSchemaHelper.unmarshal("one two three"))
             .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Integer\"");
-        assertEquals(null, longSchemaHelper.unmarshal(null));
+                + "compatible with class \"java.lang.Float\"");
+    }
+
+    private static void assertLongUnmarshal(SchemaHelper longSchemaHelper) {
+        assertNull(longSchemaHelper.unmarshal(null));
         assertEquals(123L, longSchemaHelper.unmarshal("123"));
         assertEquals(123L, longSchemaHelper.unmarshal(Integer.parseInt("123")));
         assertEquals(123L, longSchemaHelper.unmarshal(Byte.parseByte("123")));
@@ -214,38 +224,53 @@ public class JavaSchemaHelperTest {
         assertEquals(123L, longSchemaHelper.unmarshal(Double.parseDouble("123")));
         assertThatThrownBy(() -> longSchemaHelper.unmarshal("one two three"))
             .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Long\"");
-        assertEquals(null, floatSchemaHelper.unmarshal(null));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal("123"));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Integer.parseInt("123")));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Byte.parseByte("123")));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Short.parseShort("123")));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Long.parseLong("123")));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Float.parseFloat("123")));
-        assertEquals(Float.valueOf("123"), floatSchemaHelper.unmarshal(Double.parseDouble("123")));
-        assertThatThrownBy(() -> floatSchemaHelper.unmarshal("one two three"))
+                + "compatible with class \"java.lang.Long\"");
+    }
+
+    private static void assertIntUnmarshal(SchemaHelper intSchemaHelper) {
+        assertNull(intSchemaHelper.unmarshal(null));
+        assertEquals(123, intSchemaHelper.unmarshal("123"));
+        assertEquals(123, intSchemaHelper.unmarshal(Integer.parseInt("123")));
+        assertEquals(123, intSchemaHelper.unmarshal(Byte.parseByte("123")));
+        assertEquals(123, intSchemaHelper.unmarshal(Short.parseShort("123")));
+        assertEquals(123, intSchemaHelper.unmarshal(Long.parseLong("123")));
+        assertEquals(123, intSchemaHelper.unmarshal(Float.parseFloat("123")));
+        assertEquals(123, intSchemaHelper.unmarshal(Double.parseDouble("123")));
+        assertThatThrownBy(() -> intSchemaHelper.unmarshal("one two three"))
             .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Float\"");
-        assertEquals(null, doubleSchemaHelper.unmarshal(null));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal("123"));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Integer.parseInt("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Byte.parseByte("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Short.parseShort("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Long.parseLong("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Float.parseFloat("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(Double.parseDouble("123")));
-        assertEquals(Double.valueOf("123"), doubleSchemaHelper.unmarshal(BigDecimal.valueOf(123)));
-        assertThatThrownBy(() -> doubleSchemaHelper.unmarshal("one two three"))
+                + "compatible with class \"java.lang.Integer\"");
+    }
+
+    private static void assertShortUnmarshal(SchemaHelper shortSchemaHelper) {
+        assertNull(shortSchemaHelper.unmarshal(null));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal("123"));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Integer.parseInt("123")));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Byte.parseByte("123")));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Short.parseShort("123")));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Long.parseLong("123")));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Float.parseFloat("123")));
+        assertEquals(Short.valueOf("123"), shortSchemaHelper.unmarshal(Double.parseDouble("123")));
+        assertThatThrownBy(() -> shortSchemaHelper.unmarshal("one two three"))
             .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
-                    + "compatible with class \"java.lang.Double\"");
-        assertEquals("123", stringSchemaHelper.unmarshal(123));
+                + "compatible with class \"java.lang.Short\"");
+    }
 
-        SupportSubClass subClassInstance = new SupportSubClass("123");
-        assertEquals(subClassInstance, myBaseClassSchemaHelper.unmarshal(subClassInstance));
+    private static void assertByteUnmarshal(SchemaHelper byteSchemaHelper) {
+        assertNull(byteSchemaHelper.unmarshal(null));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal("123"));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Integer.parseInt("123")));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Byte.parseByte("123")));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Short.parseShort("123")));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Long.parseLong("123")));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Float.parseFloat("123")));
+        assertEquals(Byte.valueOf("123"), byteSchemaHelper.unmarshal(Double.parseDouble("123")));
+        assertThatThrownBy(() -> byteSchemaHelper.unmarshal("one two three"))
+            .hasMessage("UserKey:0.0.1: object \"one two three\" of class \"java.lang.String\" not "
+                + "compatible with class \"java.lang.Byte\"");
     }
 
     @Test
-    public void testJavaSchemaHelperMarshal() {
+    void testJavaSchemaHelperMarshal() {
         AxArtifactKey schemaKey = new AxArtifactKey("SchemaKey", "0.0.1");
         AxArtifactKey userKey = new AxArtifactKey("UserKey", "0.0.1");
 
@@ -257,13 +282,13 @@ public class JavaSchemaHelperTest {
         assertEquals("123", intSchemaHelper.marshal2String(123));
         assertThatThrownBy(() -> intSchemaHelper.marshal2String(123.45))
             .hasMessage("UserKey:0.0.1: object \"123.45\" of class \"java.lang.Double\" not "
-                    + "compatible with class \"java.lang.Integer\"");
+                + "compatible with class \"java.lang.Integer\"");
         JsonPrimitive intJsonPrimitive = (JsonPrimitive) intSchemaHelper.marshal2Object(123);
         assertEquals(123, intJsonPrimitive.getAsInt());
     }
 
     @Test
-    public void testJavaSchemaHelperAdapters() {
+    void testJavaSchemaHelperAdapters() {
         AxArtifactKey schemaKey = new AxArtifactKey("SchemaKey", "0.0.1");
         AxArtifactKey userKey = new AxArtifactKey("UserKey", "0.0.1");
 
@@ -275,22 +300,22 @@ public class JavaSchemaHelperTest {
         assertEquals("\"Hello\"", stringSchemaHelper.marshal2String("Hello"));
         assertThatThrownBy(() -> stringSchemaHelper.marshal2String(Instant.ofEpochMilli(1000)))
             .hasMessage("UserKey:0.0.1: object \"1970-01-01T00:00:01Z\" of class \"java.time.Instant\" "
-                    + "not compatible with class \"java.lang.String\"");
+                + "not compatible with class \"java.lang.String\"");
         JsonPrimitive stringJsonPrimitive = (JsonPrimitive) stringSchemaHelper.marshal2Object("Another String");
         assertEquals("Another String", stringJsonPrimitive.getAsString());
     }
 
     @Test
-    public void testJavaSchemaHelperBadAdapter() {
+    void testJavaSchemaHelperBadAdapter() {
         AxArtifactKey schemaKey = new AxArtifactKey("SchemaKey", "0.0.1");
         AxArtifactKey userKey = new AxArtifactKey("UserKey", "0.0.1");
 
         SchemaParameters pars = ParameterService.get(ContextParameterConstants.SCHEMA_GROUP_NAME);
 
         JavaSchemaHelperParameters javaShPars =
-                (JavaSchemaHelperParameters) pars.getSchemaHelperParameterMap().get("Java");
+            (JavaSchemaHelperParameters) pars.getSchemaHelperParameterMap().get("Java");
         javaShPars.getJsonAdapters().get("String")
-                .setAdaptorClass("org.onap.policy.apex.context.impl.schema.java.SupportBadJsonAdapter");
+            .setAdaptorClass("org.onap.policy.apex.context.impl.schema.java.SupportBadJsonAdapter");
 
         AxContextSchema stringSchema = new AxContextSchema(schemaKey, "Java", "java.lang.String");
         SchemaHelper stringSchemaHelper = new JavaSchemaHelper();
@@ -298,16 +323,16 @@ public class JavaSchemaHelperTest {
 
         assertThatThrownBy(() -> stringSchemaHelper.marshal2String("Hello"))
             .hasMessage("UserKey:0.0.1: instantiation of adapter class "
-                    + "\"org.onap.policy.apex.context.impl.schema.java.SupportBadJsonAdapter\"  to decode and encode "
-                    + "class \"java.lang.String\" failed: null");
+                + "\"org.onap.policy.apex.context.impl.schema.java.SupportBadJsonAdapter\"  to decode and encode "
+                + "class \"java.lang.String\" failed: null");
     }
 
     @Test
-    public void testJavaSchemaHelperDefaultAdapter() {
+    void testJavaSchemaHelperDefaultAdapter() {
         SchemaParameters pars = ParameterService.get(ContextParameterConstants.SCHEMA_GROUP_NAME);
 
         JavaSchemaHelperParameters javaShPars =
-                (JavaSchemaHelperParameters) pars.getSchemaHelperParameterMap().get("Java");
+            (JavaSchemaHelperParameters) pars.getSchemaHelperParameterMap().get("Java");
 
         pars.getSchemaHelperParameterMap().clear();
 
diff --git a/model/src/main/java/org/onap/policy/apex/model/basicmodel/test/TestApexModel.java b/model/src/main/java/org/onap/policy/apex/model/basicmodel/test/TestApexModel.java
index 9dde47d05..198552bd2 100644
--- a/model/src/main/java/org/onap/policy/apex/model/basicmodel/test/TestApexModel.java
+++ b/model/src/main/java/org/onap/policy/apex/model/basicmodel/test/TestApexModel.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2021-2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2021-2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,8 +38,8 @@ import org.slf4j.ext.XLoggerFactory;
  * This class tests reading and writing of Apex models to file and to a database using JPA. It also tests validation of
  * Apex models. This class is designed for use in unit tests in modules that define Apex models.
  *
- * @author Liam Fallon (liam.fallon@ericsson.com)
  * @param <M> the generic type
+ * @author Liam Fallon (liam.fallon@ericsson.com)
  */
 public class TestApexModel<M extends AxModel> {
     private static final String MODEL_IS_INVALID = "model is invalid ";
@@ -53,14 +53,14 @@ public class TestApexModel<M extends AxModel> {
     private final Class<M> rootModelClass;
 
     // The class that provides the model
-    private TestApexModelCreator<M> modelCreator = null;
+    private final TestApexModelCreator<M> modelCreator;
 
     /**
      * Constructor, defines the subclass of {@link AxModel} that is being tested and the {@link TestApexModelCreator}
      * object that is used to generate Apex models.
      *
-     * @param rootModelClass the Apex model class, a sub class of {@link AxModel}
-     * @param modelCreator the @link TestApexModelCreator} that will generate Apex models of various types for testing
+     * @param rootModelClass the Apex model class, a subclass of {@link AxModel}
+     * @param modelCreator   {@link TestApexModelCreator} that will generate Apex models of various types for testing
      */
     public TestApexModel(final Class<M> rootModelClass, final TestApexModelCreator<M> modelCreator) {
         this.rootModelClass = rootModelClass;
@@ -105,7 +105,7 @@ public class TestApexModel<M extends AxModel> {
             final var fileModel = modelReader.read(apexModelUrl.openStream());
             checkModelEquality(model, fileModel, TEST_MODEL_UNEQUAL_STR + jsonFile.getAbsolutePath());
         } catch (final Exception e) {
-            LOGGER.warn(ERROR_PROCESSING_FILE + jsonFile.getAbsolutePath(), e);
+            LOGGER.warn(ERROR_PROCESSING_FILE + "{}", jsonFile.getAbsolutePath(), e);
             throw new ApexException(ERROR_PROCESSING_FILE + jsonFile.getAbsolutePath(), e);
         }
 
@@ -128,18 +128,18 @@ public class TestApexModel<M extends AxModel> {
      * @throws ApexException thrown on errors validating the Apex model
      */
     public final AxValidationResult testApexModelValid() throws ApexException {
-        LOGGER.debug("running testApexModelVaid . . .");
+        LOGGER.debug("running testApexModelValid . . .");
 
         final var model = modelCreator.getModel();
         final AxValidationResult result = model.validate(new AxValidationResult());
 
         if (!result.isValid()) {
-            String message = MODEL_IS_INVALID + result.toString();
+            String message = MODEL_IS_INVALID + result;
             LOGGER.warn(message);
             throw new ApexException(message);
         }
 
-        LOGGER.debug("ran testApexModelVaid");
+        LOGGER.debug("ran testApexModelValid");
         return result;
     }
 
@@ -149,19 +149,19 @@ public class TestApexModel<M extends AxModel> {
      * @return the result of the validation
      * @throws ApexException thrown on errors validating the Apex model
      */
-    public final AxValidationResult testApexModelVaidateMalstructured() throws ApexException {
-        LOGGER.debug("running testApexModelVaidateMalstructured . . .");
+    public final AxValidationResult testApexModelValidateMalstructured() throws ApexException {
+        LOGGER.debug("running testApexModelValidateMalstructured . . .");
 
         final var model = modelCreator.getMalstructuredModel();
         final AxValidationResult result = model.validate(new AxValidationResult());
 
         if (result.isValid()) {
-            String message = "model should not be valid " + result.toString();
+            String message = "model should not be valid " + result;
             LOGGER.warn(message);
             throw new ApexException(message);
         }
 
-        LOGGER.debug("ran testApexModelVaidateMalstructured");
+        LOGGER.debug("ran testApexModelValidateMalstructured");
         return result;
     }
 
@@ -171,8 +171,8 @@ public class TestApexModel<M extends AxModel> {
      * @return the result of the validation
      * @throws ApexException thrown on errors validating the Apex model
      */
-    public final AxValidationResult testApexModelVaidateObservation() throws ApexException {
-        LOGGER.debug("running testApexModelVaidateObservation . . .");
+    public final AxValidationResult testApexModelValidateObservation() throws ApexException {
+        LOGGER.debug("running testApexModelValidateObservation . . .");
 
         final var model = modelCreator.getObservationModel();
         final AxValidationResult result = model.validate(new AxValidationResult());
@@ -188,7 +188,7 @@ public class TestApexModel<M extends AxModel> {
             throw new ApexException("model should have observations");
         }
 
-        LOGGER.debug("ran testApexModelVaidateObservation");
+        LOGGER.debug("ran testApexModelValidateObservation");
         return result;
     }
 
@@ -198,8 +198,8 @@ public class TestApexModel<M extends AxModel> {
      * @return the result of the validation
      * @throws ApexException thrown on errors validating the Apex model
      */
-    public final AxValidationResult testApexModelVaidateWarning() throws ApexException {
-        LOGGER.debug("running testApexModelVaidateWarning . . .");
+    public final AxValidationResult testApexModelValidateWarning() throws ApexException {
+        LOGGER.debug("running testApexModelValidateWarning . . .");
 
         final var model = modelCreator.getWarningModel();
         final AxValidationResult result = model.validate(new AxValidationResult());
@@ -215,7 +215,7 @@ public class TestApexModel<M extends AxModel> {
             throw new ApexException("model should have warnings");
         }
 
-        LOGGER.debug("ran testApexModelVaidateWarning");
+        LOGGER.debug("ran testApexModelValidateWarning");
         return result;
     }
 
@@ -225,27 +225,27 @@ public class TestApexModel<M extends AxModel> {
      * @return the result of the validation
      * @throws ApexException thrown on errors validating the Apex model
      */
-    public final AxValidationResult testApexModelVaidateInvalidModel() throws ApexException {
-        LOGGER.debug("running testApexModelVaidateInvalidModel . . .");
+    public final AxValidationResult testApexModelValidateInvalidModel() throws ApexException {
+        LOGGER.debug("running testApexModelValidateInvalidModel . . .");
 
         final var model = modelCreator.getInvalidModel();
         final AxValidationResult result = model.validate(new AxValidationResult());
 
         if (result.isValid()) {
-            String message = "model should not be valid " + result.toString();
+            String message = "model should not be valid " + result;
             LOGGER.warn(message);
             throw new ApexException(message);
         }
 
-        LOGGER.debug("ran testApexModelVaidateInvalidModel");
+        LOGGER.debug("ran testApexModelValidateInvalidModel");
         return result;
     }
 
     /**
      * Check if two models are equal.
      *
-     * @param leftModel the left model
-     * @param rightModel the right model
+     * @param leftModel    the left model
+     * @param rightModel   the right model
      * @param errorMessage the error message to output on inequality
      * @throws ApexException the exception to throw on inequality
      */
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxConceptGetterImplTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxConceptGetterImplTest.java
index 44a9de49e..48db5299a 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxConceptGetterImplTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxConceptGetterImplTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,22 +22,22 @@
 package org.onap.policy.apex.model.basicmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import java.util.NavigableMap;
 import java.util.TreeMap;
 import java.util.TreeSet;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test the AxConceptGetterImpl class.
  */
-public class AxConceptGetterImplTest {
+class AxConceptGetterImplTest {
 
     @Test
-    public void testAxConceptGetterImpl() {
+    void testAxConceptGetterImpl() {
         NavigableMap<AxArtifactKey, AxArtifactKey> keyMap = new TreeMap<>();
 
         AxConceptGetterImpl<AxArtifactKey> getter = new AxConceptGetterImpl<>(keyMap);
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyInfoTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyInfoTest.java
index 0c7edee28..2e6512527 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyInfoTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyInfoTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,26 +21,26 @@
 
 package org.onap.policy.apex.model.basicmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.UUID;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 
-public class AxKeyInfoTest {
+class AxKeyInfoTest {
 
     @Test
-    public void testNullAxKeyInfo() {
+    void testNullAxKeyInfo() {
         assertNotNull(new AxKeyInfo());
         assertNotNull(new AxKeyInfo(new AxArtifactKey()));
         assertNotNull(new AxKeyInfo(new AxArtifactKey(), UUID.randomUUID(), "Key description"));
     }
 
     @Test
-    public void testAxKeyInfo() {
+    void testAxKeyInfo() {
         AxKeyInfo testKeyInfo = new AxKeyInfo();
         testKeyInfo.setKey((new AxArtifactKey("PN", "0.0.1")));
         assertEquals("PN:0.0.1", testKeyInfo.getKey().getId());
@@ -72,14 +72,11 @@ public class AxKeyInfoTest {
         assertEquals(testKeyInfo, new AxKeyInfo(key, uuid, "Some Other Description"));
         assertEquals(testKeyInfo, new AxKeyInfo(key, uuid, "Key Description"));
 
-        assertEquals(0, testKeyInfo.compareTo(testKeyInfo));
         assertEquals(0, testKeyInfo.compareTo(clonedReferenceKey));
-
-
     }
 
     @Test
-    public void testAxKeyValidation() {
+    void testAxKeyValidation() {
         AxKeyInfo testKeyInfo = new AxKeyInfo();
         testKeyInfo.setKey((new AxArtifactKey("PN", "0.0.1")));
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyTest.java
index 010f4b8a3..b181c2d41 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2021 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2021, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,18 +22,18 @@
 package org.onap.policy.apex.model.basicmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.lang.reflect.Field;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey.Compatibility;
 
-public class AxKeyTest {
+class AxKeyTest {
 
     private static AxArtifactKey someKey0;
     private static AxArtifactKey someKey1;
@@ -46,8 +46,8 @@ public class AxKeyTest {
     /**
      * Sets data in Keys for the tests.
      */
-    @Before
-    public void setKeys() {
+    @BeforeEach
+    void setKeys() {
         someKey0 = new AxArtifactKey();
         someKey1 = new AxArtifactKey("name", "0.0.1");
         someKey2 = new AxArtifactKey(someKey1);
@@ -67,10 +67,10 @@ public class AxKeyTest {
     }
 
     @Test
-    public void testArtifactKey() {
+    void testArtifactKey() {
         assertThatThrownBy(() -> new AxArtifactKey("some bad key id"))
             .hasMessage("parameter \"id\": value \"some bad key id\", "
-                            + "does not match regular expression \"[A-Za-z0-9\\-_\\.]+:[0-9].[0-9].[0-9]\"");
+                + "does not match regular expression \"[A-Za-z0-9\\-_\\.]+:[0-9].[0-9].[0-9]\"");
 
         assertEquals(AxArtifactKey.getNullKey(), someKey0);
 
@@ -92,7 +92,6 @@ public class AxKeyTest {
 
         assertThatThrownBy(() -> someKey0.compareTo(null))
             .hasMessage("comparison object may not be null");
-        assertEquals(0, someKey0.compareTo(someKey0));
         assertEquals(353602977, someKey0.compareTo(new AxReferenceKey()));
 
         assertNotNull(someKey0);
@@ -102,7 +101,7 @@ public class AxKeyTest {
     }
 
     @Test
-    public void testAxCompatibility() {
+    void testAxCompatibility() {
         setKeyValues();
 
         assertEquals(Compatibility.DIFFERENT, someKey0.getCompatibility(new AxReferenceKey()));
@@ -122,27 +121,27 @@ public class AxKeyTest {
     }
 
     @Test
-    public void testAxValidation() {
+    void testAxValidation() {
         setKeyValues();
 
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey0.validate(new AxValidationResult()).getValidationResult());
+            someKey0.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey1.validate(new AxValidationResult()).getValidationResult());
+            someKey1.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey2.validate(new AxValidationResult()).getValidationResult());
+            someKey2.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey3.validate(new AxValidationResult()).getValidationResult());
+            someKey3.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey4.validate(new AxValidationResult()).getValidationResult());
+            someKey4.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey5.validate(new AxValidationResult()).getValidationResult());
+            someKey5.validate(new AxValidationResult()).getValidationResult());
         assertEquals(AxValidationResult.ValidationResult.VALID,
-                        someKey6.validate(new AxValidationResult()).getValidationResult());
+            someKey6.validate(new AxValidationResult()).getValidationResult());
     }
 
     @Test
-    public void testNullKey() {
+    void testNullKey() {
         setKeyValues();
 
         AxArtifactKey nullKey0 = AxArtifactKey.getNullKey();
@@ -157,7 +156,7 @@ public class AxKeyTest {
 
 
     @Test
-    public void testValidation() throws IllegalArgumentException, IllegalAccessException,
+    void testValidation() throws IllegalArgumentException, IllegalAccessException,
         NoSuchFieldException, SecurityException {
         AxArtifactKey testKey = new AxArtifactKey("TheKey", "0.0.1");
         assertEquals("TheKey:0.0.1", testKey.getId());
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyUseTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyUseTest.java
index 5346b6b21..d2c82a89a 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyUseTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxKeyUseTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,18 +21,18 @@
 
 package org.onap.policy.apex.model.basicmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey.Compatibility;
 
-public class AxKeyUseTest {
+class AxKeyUseTest {
 
     @Test
-    public void test() {
+    void test() {
         assertNotNull(new AxKeyUse());
         assertNotNull(new AxKeyUse(new AxArtifactKey()));
         assertNotNull(new AxKeyUse(new AxReferenceKey()));
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxReferenceKeyTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxReferenceKeyTest.java
index 515587558..a39756ed6 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxReferenceKeyTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/AxReferenceKeyTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,58 +22,28 @@
 package org.onap.policy.apex.model.basicmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.lang.reflect.Field;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 
-public class AxReferenceKeyTest {
+class AxReferenceKeyTest {
 
     @Test
-    public void testAxReferenceKey() {
-        assertNotNull(new AxReferenceKey());
-        assertNotNull(new AxReferenceKey(new AxArtifactKey()));
-        assertNotNull(new AxReferenceKey(new AxArtifactKey(), "LocalName"));
-        assertNotNull(new AxReferenceKey(new AxReferenceKey()));
-        assertNotNull(new AxReferenceKey(new AxReferenceKey(), "LocalName"));
-        assertNotNull(new AxReferenceKey(new AxArtifactKey(), "ParentLocalName", "LocalName"));
-        assertNotNull(new AxReferenceKey("ParentKeyName", "0.0.1", "LocalName"));
-        assertNotNull(new AxReferenceKey("ParentKeyName", "0.0.1", "ParentLocalName", "LocalName"));
-        assertNotNull(new AxReferenceKey("ParentKeyName:0.0.1:ParentLocalName:LocalName"));
+    void testAxReferenceKey() {
+        assertConstructor();
         assertEquals(AxReferenceKey.getNullKey().getKey(), AxReferenceKey.getNullKey());
         assertEquals("NULL:0.0.0:NULL:NULL", AxReferenceKey.getNullKey().getId());
 
         AxReferenceKey testReferenceKey = new AxReferenceKey();
-        testReferenceKey.setParentArtifactKey(new AxArtifactKey("PN", "0.0.1"));
-        assertEquals("PN:0.0.1", testReferenceKey.getParentArtifactKey().getId());
-
-        testReferenceKey.setParentReferenceKey(new AxReferenceKey("PN", "0.0.1", "LN"));
-        assertEquals("PN:0.0.1:NULL:LN", testReferenceKey.getParentReferenceKey().getId());
-
-        testReferenceKey.setParentKeyName("NPKN");
-        assertEquals("NPKN", testReferenceKey.getParentKeyName());
-
-        testReferenceKey.setParentKeyVersion("0.0.1");
-        assertEquals("0.0.1", testReferenceKey.getParentKeyVersion());
-
-        testReferenceKey.setParentLocalName("NPKLN");
-        assertEquals("NPKLN", testReferenceKey.getParentLocalName());
+        assertSetValues(testReferenceKey);
 
-        testReferenceKey.setLocalName("NLN");
-        assertEquals("NLN", testReferenceKey.getLocalName());
-
-        assertFalse(testReferenceKey.isCompatible(AxArtifactKey.getNullKey()));
-        assertFalse(testReferenceKey.isCompatible(AxReferenceKey.getNullKey()));
-        assertTrue(testReferenceKey.isCompatible(testReferenceKey));
-
-        assertEquals(AxKey.Compatibility.DIFFERENT, testReferenceKey.getCompatibility(AxArtifactKey.getNullKey()));
-        assertEquals(AxKey.Compatibility.DIFFERENT, testReferenceKey.getCompatibility(AxReferenceKey.getNullKey()));
-        assertEquals(AxKey.Compatibility.IDENTICAL, testReferenceKey.getCompatibility(testReferenceKey));
+        assertCompatibility(testReferenceKey);
 
         AxValidationResult result = new AxValidationResult();
         result = testReferenceKey.validate(result);
@@ -96,6 +66,16 @@ public class AxReferenceKeyTest {
         assertNotEquals(testReferenceKey, new AxReferenceKey("NPKN", "0.0.1", "NPLN", "LN"));
         assertEquals(testReferenceKey, new AxReferenceKey("NPKN", "0.0.1", "NPKLN", "NLN"));
 
+        assertCompareTo(testReferenceKey, clonedReferenceKey);
+
+        assertNotNull(testReferenceKey.getKeys());
+
+        assertExceptions(testReferenceKey);
+        AxReferenceKey targetRefKey = new AxReferenceKey();
+        assertEquals(testReferenceKey, testReferenceKey.copyTo(targetRefKey));
+    }
+
+    private static void assertCompareTo(AxReferenceKey testReferenceKey, AxReferenceKey clonedReferenceKey) {
         assertEquals(0, testReferenceKey.compareTo(testReferenceKey));
         assertEquals(0, testReferenceKey.compareTo(clonedReferenceKey));
         assertNotEquals(0, testReferenceKey.compareTo(new AxArtifactKey()));
@@ -104,9 +84,9 @@ public class AxReferenceKeyTest {
         assertNotEquals(0, testReferenceKey.compareTo(new AxReferenceKey("NPKN", "0.0.1", "PLN", "LN")));
         assertNotEquals(0, testReferenceKey.compareTo(new AxReferenceKey("NPKN", "0.0.1", "NPLN", "LN")));
         assertEquals(0, testReferenceKey.compareTo(new AxReferenceKey("NPKN", "0.0.1", "NPKLN", "NLN")));
+    }
 
-        assertNotNull(testReferenceKey.getKeys());
-
+    private static void assertExceptions(AxReferenceKey testReferenceKey) {
         assertThatThrownBy(() -> testReferenceKey.equals(null))
             .hasMessage("comparison object may not be null");
         assertThatThrownBy(() -> testReferenceKey.copyTo(null))
@@ -114,12 +94,52 @@ public class AxReferenceKeyTest {
         assertThatThrownBy(() -> testReferenceKey.copyTo(new AxArtifactKey("Key", "0.0.1")))
             .hasMessage("org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey is not an instance of "
                 + "org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey");
-        AxReferenceKey targetRefKey = new AxReferenceKey();
-        assertEquals(testReferenceKey, testReferenceKey.copyTo(targetRefKey));
+    }
+
+    private static void assertCompatibility(AxReferenceKey testReferenceKey) {
+        assertFalse(testReferenceKey.isCompatible(AxArtifactKey.getNullKey()));
+        assertFalse(testReferenceKey.isCompatible(AxReferenceKey.getNullKey()));
+        assertTrue(testReferenceKey.isCompatible(testReferenceKey));
+
+        assertEquals(AxKey.Compatibility.DIFFERENT, testReferenceKey.getCompatibility(AxArtifactKey.getNullKey()));
+        assertEquals(AxKey.Compatibility.DIFFERENT, testReferenceKey.getCompatibility(AxReferenceKey.getNullKey()));
+        assertEquals(AxKey.Compatibility.IDENTICAL, testReferenceKey.getCompatibility(testReferenceKey));
+    }
+
+    private static void assertSetValues(AxReferenceKey testReferenceKey) {
+        testReferenceKey.setParentArtifactKey(new AxArtifactKey("PN", "0.0.1"));
+        assertEquals("PN:0.0.1", testReferenceKey.getParentArtifactKey().getId());
+
+        testReferenceKey.setParentReferenceKey(new AxReferenceKey("PN", "0.0.1", "LN"));
+        assertEquals("PN:0.0.1:NULL:LN", testReferenceKey.getParentReferenceKey().getId());
+
+        testReferenceKey.setParentKeyName("NPKN");
+        assertEquals("NPKN", testReferenceKey.getParentKeyName());
+
+        testReferenceKey.setParentKeyVersion("0.0.1");
+        assertEquals("0.0.1", testReferenceKey.getParentKeyVersion());
+
+        testReferenceKey.setParentLocalName("NPKLN");
+        assertEquals("NPKLN", testReferenceKey.getParentLocalName());
+
+        testReferenceKey.setLocalName("NLN");
+        assertEquals("NLN", testReferenceKey.getLocalName());
+    }
+
+    private static void assertConstructor() {
+        assertNotNull(new AxReferenceKey());
+        assertNotNull(new AxReferenceKey(new AxArtifactKey()));
+        assertNotNull(new AxReferenceKey(new AxArtifactKey(), "LocalName"));
+        assertNotNull(new AxReferenceKey(new AxReferenceKey()));
+        assertNotNull(new AxReferenceKey(new AxReferenceKey(), "LocalName"));
+        assertNotNull(new AxReferenceKey(new AxArtifactKey(), "ParentLocalName", "LocalName"));
+        assertNotNull(new AxReferenceKey("ParentKeyName", "0.0.1", "LocalName"));
+        assertNotNull(new AxReferenceKey("ParentKeyName", "0.0.1", "ParentLocalName", "LocalName"));
+        assertNotNull(new AxReferenceKey("ParentKeyName:0.0.1:ParentLocalName:LocalName"));
     }
 
     @Test
-    public void testValidation() throws IllegalArgumentException, IllegalAccessException,
+    void testValidation() throws IllegalArgumentException, IllegalAccessException,
         NoSuchFieldException, SecurityException {
         AxReferenceKey testReferenceKey = new AxReferenceKey();
         testReferenceKey.setParentArtifactKey(new AxArtifactKey("PN", "0.0.1"));
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ExceptionsTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ExceptionsTest.java
index ff87bc2d0..921b406b0 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ExceptionsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ExceptionsTest.java
@@ -1,6 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,32 +21,24 @@
 
 package org.onap.policy.apex.model.basicmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 
-public class ExceptionsTest {
+class ExceptionsTest {
 
     @Test
-    public void test() {
-        assertNotNull(new ApexException("Message"));
-        assertNotNull(new ApexException("Message", new AxArtifactKey()));
-        assertNotNull(new ApexException("Message", new IOException()));
-        assertNotNull(new ApexException("Message", new IOException(), new AxArtifactKey()));
+    void test() {
+        assertConstructors();
 
         AxArtifactKey key = new AxArtifactKey();
         ApexException ae = new ApexException("Message", new IOException("IO exception message"), key);
         assertEquals("Message\ncaused by: Message\ncaused by: IO exception message", ae.getCascadedMessage());
         assertEquals(key, ae.getObject());
 
-        assertNotNull(new ApexRuntimeException("Message"));
-        assertNotNull(new ApexRuntimeException("Message", new AxArtifactKey()));
-        assertNotNull(new ApexRuntimeException("Message", new IOException()));
-        assertNotNull(new ApexRuntimeException("Message", new IOException(), new AxArtifactKey()));
-
         AxArtifactKey rkey = new AxArtifactKey();
         ApexRuntimeException re = new ApexRuntimeException("Runtime Message",
                         new IOException("IO runtime exception message"), rkey);
@@ -53,9 +46,6 @@ public class ExceptionsTest {
                         re.getCascadedMessage());
         assertEquals(key, re.getObject());
 
-        assertNotNull(new ApexConceptException("Message"));
-        assertNotNull(new ApexConceptException("Message", new IOException()));
-
         AxArtifactKey ckey = new AxArtifactKey();
         ApexException ace = new ApexException("Concept Message", new IOException("IO concept exception message"), ckey);
         assertEquals("Concept Message\ncaused by: Concept Message\ncaused by: IO concept exception message",
@@ -63,4 +53,19 @@ public class ExceptionsTest {
         assertEquals(ckey, ace.getObject());
     }
 
+    private static void assertConstructors() {
+        assertNotNull(new ApexException("Message"));
+        assertNotNull(new ApexException("Message", new AxArtifactKey()));
+        assertNotNull(new ApexException("Message", new IOException()));
+        assertNotNull(new ApexException("Message", new IOException(), new AxArtifactKey()));
+
+        assertNotNull(new ApexRuntimeException("Message"));
+        assertNotNull(new ApexRuntimeException("Message", new AxArtifactKey()));
+        assertNotNull(new ApexRuntimeException("Message", new IOException()));
+        assertNotNull(new ApexRuntimeException("Message", new IOException(), new AxArtifactKey()));
+
+        assertNotNull(new ApexConceptException("Message"));
+        assertNotNull(new ApexConceptException("Message", new IOException()));
+    }
+
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ValidationTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ValidationTest.java
index 21ae9b65c..c5ed19ff3 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ValidationTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/concepts/ValidationTest.java
@@ -1,90 +1,93 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.basicmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.ValidationResult;
 
-public class ValidationTest {
+class ValidationTest {
 
     @Test
-    public void test() {
+    void testValid() {
         AxValidationResult result = new AxValidationResult();
         AxReferenceKey refKey = new AxReferenceKey("PK", "0.0.1", "PLN", "LN");
         result = refKey.validate(result);
-
-        assertNotNull(result);
-        assertTrue(result.isOk());
-        assertTrue(result.isValid());
-        assertEquals(AxValidationResult.ValidationResult.VALID, result.getValidationResult());
-        assertNotNull(result.getMessageList());
+        assertResultIsValid(result, ValidationResult.VALID);
 
         AxValidationMessage vmess0 = new AxValidationMessage(AxArtifactKey.getNullKey(), AxArtifactKey.class,
-                        ValidationResult.VALID, "Some message");
+            ValidationResult.VALID, "Some message");
         result.addValidationMessage(vmess0);
-
-        assertTrue(result.isOk());
-        assertTrue(result.isValid());
-        assertEquals(AxValidationResult.ValidationResult.VALID, result.getValidationResult());
-        assertNotNull(result.getMessageList());
-        assertNotNull("hello", result.toString());
+        assertResultIsValid(result, ValidationResult.VALID);
 
         AxValidationMessage vmess1 = new AxValidationMessage(AxArtifactKey.getNullKey(), AxArtifactKey.class,
-                        ValidationResult.OBSERVATION, "Some message");
+            ValidationResult.OBSERVATION, "Some message");
         result.addValidationMessage(vmess1);
+        assertResultIsValid(result, ValidationResult.OBSERVATION);
+    }
 
-        assertTrue(result.isOk());
-        assertTrue(result.isValid());
-        assertEquals(AxValidationResult.ValidationResult.OBSERVATION, result.getValidationResult());
-        assertNotNull(result.getMessageList());
-        assertNotNull("hello", result.toString());
-
+    @Test
+    void testWarning() {
+        AxValidationResult result = new AxValidationResult();
         AxValidationMessage vmess2 = new AxValidationMessage(AxArtifactKey.getNullKey(), AxArtifactKey.class,
-                        ValidationResult.WARNING, "Some message");
+            ValidationResult.WARNING, "Some message");
         result.addValidationMessage(vmess2);
 
         assertFalse(result.isOk());
         assertTrue(result.isValid());
         assertEquals(AxValidationResult.ValidationResult.WARNING, result.getValidationResult());
         assertNotNull(result.getMessageList());
-        assertNotNull("hello", result.toString());
+        assertNotNull(result.toString());
+    }
 
+    @Test
+    void testInvalid() {
+        AxValidationResult result = new AxValidationResult();
         AxValidationMessage vmess3 = new AxValidationMessage(AxArtifactKey.getNullKey(), AxArtifactKey.class,
-                        ValidationResult.INVALID, "Some message");
+            ValidationResult.INVALID, "Some message");
         result.addValidationMessage(vmess3);
 
         assertFalse(result.isOk());
         assertFalse(result.isValid());
         assertEquals(AxValidationResult.ValidationResult.INVALID, result.getValidationResult());
         assertNotNull(result.getMessageList());
-        assertNotNull("hello", result.toString());
+        assertNotNull(result.toString());
 
-        assertEquals(AxValidationResult.ValidationResult.INVALID, result.getMessageList().get(3).getValidationResult());
-        assertEquals("Some message", result.getMessageList().get(3).getMessage());
-        assertEquals(AxArtifactKey.class.getName(), result.getMessageList().get(3).getObservedClass());
-        assertEquals(AxArtifactKey.getNullKey(), result.getMessageList().get(3).getObservedKey());
+        var otherResult = result.getMessageList().get(0);
+        assertEquals(AxValidationResult.ValidationResult.INVALID, otherResult.getValidationResult());
+        assertEquals("Some message", otherResult.getMessage());
+        assertEquals(AxArtifactKey.class.getName(), otherResult.getObservedClass());
+        assertEquals(AxArtifactKey.getNullKey(), otherResult.getObservedKey());
+    }
+
+    private static void assertResultIsValid(AxValidationResult result, ValidationResult valid) {
+        assertNotNull(result);
+        assertTrue(result.isOk());
+        assertTrue(result.isValid());
+        assertEquals(valid, result.getValidationResult());
+        assertNotNull(result.getMessageList());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelExceptionTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelExceptionTest.java
index 2571ea65b..badb57ac6 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelExceptionTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelExceptionTest.java
@@ -1,35 +1,36 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.basicmodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-public class ApexModelExceptionTest {
+class ApexModelExceptionTest {
 
     @Test
-    public void test() {
+    void test() {
         assertNotNull(new ApexModelException("Message"));
         assertNotNull(new ApexModelException("Message", new IOException()));
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelFileWriterTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelFileWriterTest.java
index 0f8f956ab..12bbd99d3 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelFileWriterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelFileWriterTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,18 +22,18 @@
 package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.File;
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
-public class ApexModelFileWriterTest {
+class ApexModelFileWriterTest {
 
     @Test
-    public void testModelFileWriter() throws IOException, ApexException {
+    void testModelFileWriter() throws IOException, ApexException {
         ApexModelFileWriter<AxModel> modelFileWriter = new ApexModelFileWriter<>(true);
 
         modelFileWriter.setValidate(true);
@@ -48,25 +48,20 @@ public class ApexModelFileWriterTest {
 
         modelFileWriter.apexModelWriteJsonFile(model, AxModel.class, jsonTempFile.getAbsolutePath());
 
-        jsonTempFile.delete();
-        new File(tempDir.getAbsolutePath() + "/aaa").delete();
-        new File(tempDir.getAbsolutePath() + "/ccc").delete();
+        assertFileDeleted(jsonTempFile);
+        assertFileDeleted(new File(tempDir.getAbsolutePath() + "/aaa"));
 
         jsonTempFile = new File(tempDir.getAbsolutePath() + "/aaa/bbb/ApexFileWriterTest.json");
 
         modelFileWriter.apexModelWriteJsonFile(model, AxModel.class, jsonTempFile.getAbsolutePath());
 
-        jsonTempFile.delete();
+        assertFileDeleted(jsonTempFile);
 
-        new File(tempDir.getAbsolutePath() + "/aaa/bbb").delete();
-        new File(tempDir.getAbsolutePath() + "/aaa").delete();
-        new File(tempDir.getAbsolutePath() + "/ccc/ddd").delete();
-        new File(tempDir.getAbsolutePath() + "/ccc").delete();
+        assertFileDeleted(new File(tempDir.getAbsolutePath() + "/aaa/bbb"));
+        assertFileDeleted(new File(tempDir.getAbsolutePath() + "/aaa"));
 
         File dirA = new File(tempDir.getAbsolutePath() + "/aaa");
-        // File dirB = new File(tempDir.getAbsolutePath() + "/aaa/bbb");
-        dirA.createNewFile();
-        // dirB.createNewFile();
+        assertTrue(dirA.createNewFile());
 
         jsonTempFile = new File(tempDir.getAbsolutePath() + "/aaa/bbb/ApexFileWriterTest.json");
         final File jsonTempFile01 = jsonTempFile;
@@ -74,12 +69,12 @@ public class ApexModelFileWriterTest {
             () -> modelFileWriter.apexModelWriteJsonFile(model, AxModel.class, jsonTempFile01.getAbsolutePath()))
                 .hasMessageContaining("could not create directory");
 
-        dirA.delete();
+        assertFileDeleted(dirA);
 
         dirA = new File(tempDir.getAbsolutePath() + "/aaa");
         File fileB = new File(tempDir.getAbsolutePath() + "/aaa/bbb");
-        dirA.mkdir();
-        fileB.createNewFile();
+        assertTrue(dirA.mkdir());
+        assertTrue(fileB.createNewFile());
 
         jsonTempFile = new File(tempDir.getAbsolutePath() + "/aaa/bbb/ApexFileWriterTest.json");
 
@@ -88,7 +83,11 @@ public class ApexModelFileWriterTest {
             () -> modelFileWriter.apexModelWriteJsonFile(model, AxModel.class, jsonTempFile02.getAbsolutePath()))
                 .hasMessageContaining("error processing file");
 
-        fileB.delete();
-        dirA.delete();
+        assertFileDeleted(fileB);
+        assertFileDeleted(dirA);
+    }
+
+    private void assertFileDeleted(File file) {
+        assertTrue(file.delete());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelReaderTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelReaderTest.java
index ae14702ef..4744731a7 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelReaderTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelReaderTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022-2023 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022-2024 Nordix Foundation
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,9 +23,9 @@
 package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.BufferedReader;
 import java.io.ByteArrayInputStream;
@@ -34,20 +34,21 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileReader;
 import java.io.IOException;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.junit.MockitoJUnitRunner;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.junit.jupiter.MockitoExtension;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
-@RunWith(MockitoJUnitRunner.class)
-public class ApexModelReaderTest {
+@ExtendWith(MockitoExtension.class)
+class ApexModelReaderTest {
+
     @Test
-    public void testModelReader() throws IOException, ApexException {
+    void testModelReader() throws IOException, ApexException {
         AxModel model = new DummyApexBasicModelCreator().getModel();
         AxModel invalidModel = new DummyApexBasicModelCreator().getInvalidModel();
 
-        ApexModelWriter<AxModel> modelWriter = new ApexModelWriter<AxModel>(AxModel.class);
+        ApexModelWriter<AxModel> modelWriter = new ApexModelWriter<>(AxModel.class);
         modelWriter.setValidate(true);
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -57,7 +58,7 @@ public class ApexModelReaderTest {
         modelWriter.setValidate(false);
         modelWriter.write(invalidModel, baosInvalid);
 
-        ApexModelReader<AxModel> modelReader = new ApexModelReader<AxModel>(AxModel.class, true);
+        ApexModelReader<AxModel> modelReader = new ApexModelReader<>(AxModel.class, true);
 
         modelReader.setValidate(true);
         assertTrue(modelReader.isValidate());
@@ -87,19 +88,17 @@ public class ApexModelReaderTest {
         ByteArrayInputStream baisDummy = new ByteArrayInputStream(dummyString.getBytes());
         assertThatThrownBy(() -> modelReader.read(baisDummy))
             .hasMessageContaining("Unable to unmarshal Apex concept");
-        ByteArrayInputStream nullBais = null;
-        assertThatThrownBy(() -> modelReader.read(nullBais))
+        assertThatThrownBy(() -> modelReader.read((java.io.InputStream) null))
             .hasMessage("concept stream may not be null");
 
         assertThatThrownBy(() -> {
-            FileInputStream fis = new FileInputStream(new File("somewhere/over/the/rainbow"));
+            FileInputStream fis = new FileInputStream("somewhere/over/the/rainbow");
             modelReader.read(fis);
         }).hasMessageContaining("rainbow");
         final File tempFile = File.createTempFile("Apex", "Dummy");
         BufferedReader br = new BufferedReader(new FileReader(tempFile));
         br.close();
-        assertThatThrownBy(() -> modelReader.read(br))
-             .hasMessage("Unable to read Apex concept ");
-        tempFile.delete();
+        assertThatThrownBy(() -> modelReader.read(br)).hasMessage("Unable to read Apex concept ");
+        assertTrue(tempFile.delete());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelSaverTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelSaverTest.java
index c95106aa8..53fa1062e 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelSaverTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelSaverTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,20 +21,20 @@
 
 package org.onap.policy.apex.model.basicmodel.handling;
 
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
-public class ApexModelSaverTest {
+class ApexModelSaverTest {
 
     @Test
-    public void testModelSaver() throws IOException, ApexException {
+    void testModelSaver() throws IOException, ApexException {
         AxModel model = new DummyApexBasicModelCreator().getModel();
         assertNotNull(model);
 
@@ -42,7 +42,7 @@ public class ApexModelSaverTest {
         assertNotNull(tempPath);
 
         ApexModelSaver<AxModel> modelSaver =
-            new ApexModelSaver<AxModel>(AxModel.class, model, tempPath.toAbsolutePath().toString());
+            new ApexModelSaver<>(AxModel.class, model, tempPath.toAbsolutePath().toString());
         assertNotNull(modelSaver);
         modelSaver.apexModelWriteJson();
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelStringWriterTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelStringWriterTest.java
index 13e72d3e2..1c13d9d5b 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelStringWriterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelStringWriterTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,19 +22,18 @@
 package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
-public class ApexModelStringWriterTest {
+class ApexModelStringWriterTest {
 
     @Test
-    public void testModelStringWriter() throws IOException, ApexException {
+    void testModelStringWriter() throws ApexException {
         AxModel basicModel = new DummyApexBasicModelCreator().getModel();
         assertNotNull(basicModel);
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelWriterTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelWriterTest.java
index 3d59652b7..55f4975d0 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelWriterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/ApexModelWriterTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022-2023 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022-2024 Nordix Foundation
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,21 +23,21 @@
 package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
 @ExtendWith(MockitoExtension.class)
-public class ApexModelWriterTest {
+class ApexModelWriterTest {
+
     @Test
-    public void testModelWriter() throws IOException, ApexException {
-        ApexModelWriter<AxModel> modelWriter = new ApexModelWriter<AxModel>(AxModel.class);
+    void testModelWriter() throws ApexException {
+        ApexModelWriter<AxModel> modelWriter = new ApexModelWriter<>(AxModel.class);
 
         modelWriter.setValidate(true);
         assertTrue(modelWriter.isValidate());
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/DummyAxModelWithReferences.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/DummyAxModelWithReferences.java
index 887755d03..7a1ab82f7 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/DummyAxModelWithReferences.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/DummyAxModelWithReferences.java
@@ -1,41 +1,47 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.basicmodel.handling;
 
+import java.io.Serial;
 import java.util.ArrayList;
 import java.util.List;
+import lombok.Getter;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 
+@Getter
 public class DummyAxModelWithReferences extends AxModel {
+
+    @Serial
     private static final long serialVersionUID = -8194956638511120008L;
 
-    private List<AxKey> extrakeyList = new ArrayList<>();
-    
+    private final List<AxKey> extrakeyList = new ArrayList<>();
+
     public DummyAxModelWithReferences(final AxArtifactKey key) {
         super(key);
     }
-    
+
     @Override
     public List<AxKey> getKeys() {
         List<AxKey> keys = super.getKeys();
@@ -44,27 +50,23 @@ public class DummyAxModelWithReferences extends AxModel {
         return keys;
     }
 
-    public List<AxKey> getExtrakeyList() {
-        return extrakeyList;
-    }
-
     /**
      * Set the reference key list.
      */
     public void setReferenceKeyList() {
         List<AxKey> keys = super.getKeys();
-        
-        for (AxKey key: keys) {
+
+        for (AxKey key : keys) {
             AxArtifactKey akey = (AxArtifactKey) key;
             AxReferenceKey keyRef = new AxReferenceKey(akey, akey.getName());
             extrakeyList.add(keyRef);
         }
     }
-    
+
     public void addKey(final AxKey akey) {
         extrakeyList.add(akey);
     }
-    
+
     public void removeKey(final AxKey akey) {
         extrakeyList.remove(akey);
     }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelConceptsTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelConceptsTest.java
index 905a27f38..d75834547 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelConceptsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelConceptsTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2021 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2021, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,15 +21,15 @@
 
 package org.onap.policy.apex.model.basicmodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.List;
 import java.util.Set;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo;
@@ -42,16 +42,16 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
 import org.onap.policy.apex.model.basicmodel.service.ModelService;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 
-public class SupportApexBasicModelConceptsTest {
+class SupportApexBasicModelConceptsTest {
     TestApexModel<AxModel> testApexModel;
 
-    @Before
-    public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxModel>(AxModel.class, new DummyApexBasicModelCreator());
+    @BeforeEach
+    void setup() {
+        testApexModel = new TestApexModel<>(AxModel.class, new DummyApexBasicModelCreator());
     }
 
     @Test
-    public void testModelConcepts() {
+    void testModelConcepts() {
         final AxModel model = testApexModel.getModel();
         assertNotNull(model);
         model.clean();
@@ -94,7 +94,7 @@ public class SupportApexBasicModelConceptsTest {
     }
 
     @Test
-    public void testKeyInformation() {
+    void testKeyInformation() {
 
         final AxModel model = testApexModel.getModel();
         final AxKeyInformation keyI = model.getKeyInformation();
@@ -147,11 +147,11 @@ public class SupportApexBasicModelConceptsTest {
     }
 
     @Test
-    public void testClonedKey() {
+    void testClonedKey() {
         final AxModel model = testApexModel.getModel();
         final AxKeyInformation keyI = model.getKeyInformation();
         final AxKeyInformation clonedKeyI = new AxKeyInformation(keyI);
-        AxValidationResult result = new AxValidationResult();
+        AxValidationResult result;
 
         clonedKeyI.setKey(AxArtifactKey.getNullKey());
         result = new AxValidationResult();
@@ -217,7 +217,7 @@ public class SupportApexBasicModelConceptsTest {
     }
 
     @Test
-    public void testModelConceptsWithReferences() {
+    void testModelConceptsWithReferences() {
         final DummyAxModelWithReferences mwr = new DummyApexBasicModelCreator().getModelWithReferences();
         assertNotNull(mwr);
         mwr.getKeyInformation().getKeyInfoMap().clear();
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelTest.java
index 68f755886..8c1f756c1 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportApexBasicModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020-2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020-2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,95 +22,71 @@
 package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
+import org.onap.policy.common.utils.resources.ResourceUtils;
 
-public class SupportApexBasicModelTest {
-    // As there are no real concepts in a basic model, this is as near to a valid model as we can get
-    private static final String VALID_MODEL_STRING = "\n" + "***warnings issued during validation of model***\n"
-                    + "AxArtifactKey:(name=FloatKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n"
-                    + "AxArtifactKey:(name=IntegerKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n" + "********************************";
-
-    private static final String WARNING_MODEL_STRING = "\n" + "***warnings issued during validation of model***\n"
-                    + "AxArtifactKey:(name=FloatKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n"
-                    + "AxArtifactKey:(name=IntegerKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n"
-                    + "AxArtifactKey:(name=Unref0,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n"
-                    + "AxArtifactKey:(name=Unref1,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts"
-                    + ".AxModel:WARNING:key not found for key information entry\n" + "********************************";
+class SupportApexBasicModelTest {
 
-    private static final String INVALID_MODEL_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000\n"
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxKeyInfo:OBSERVATION:description is blank\n"
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000\n"
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxKeyInformation:INVALID:duplicate UUID found on keyInfoMap entry AxArtifactKey:"
-                    + "(name=KeyInfoMapKey,version=0.0.1):00000000-0000-0000-0000-000000000000\n"
-                    + "********************************";
 
-    private static final String INVALID_MODEL_MALSTRUCTURED_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000\n"
-                    + "AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts."
-                    + "AxModel:INVALID:key information not found for key "
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)\n" + "********************************";
+    // As there are no real concepts in a basic model, this is as near to a valid model as we can get
+    private static final String VALID_MODEL_STRING = "basicmodel/handling/SupportApexBasicModelTest_ValidModel.txt";
+    private static final String WARNING_MODEL_STRING = "basicmodel/handling/SupportApexBasicModelTest_WarningModel.txt";
+    private static final String INVALID_MODEL_STRING = "basicmodel/handling/SupportApexBasicModelTest_InvalidModel.txt";
+    private static final String INVALID_MODEL_MALSTRUCTURED_STRING =
+        "basicmodel/handling/SupportApexBasicModelTest_InvalidModelMalStructured.txt";
 
     TestApexModel<AxModel> testApexModel;
 
     /**
      * Set up the test.
-     *
-     * @throws Exception any exception thrown by the test
      */
-    @Before
-    public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxModel>(AxModel.class, new DummyApexBasicModelCreator());
+    @BeforeEach
+    void setup() {
+        testApexModel = new TestApexModel<>(AxModel.class, new DummyApexBasicModelCreator());
     }
 
     @Test
-    public void testModelValid() throws Exception {
+    void testModelValid() throws Exception {
         final AxValidationResult result = testApexModel.testApexModelValid();
-        assertEquals(VALID_MODEL_STRING, result.toString());
+        var expectedResult = ResourceUtils.getResourceAsString(VALID_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateObservation() throws Exception {
-        assertThatThrownBy(testApexModel::testApexModelVaidateObservation)
+    void testApexModelValidateObservation() {
+        assertThatThrownBy(testApexModel::testApexModelValidateObservation)
             .hasMessage("model should have observations");
     }
 
     @Test
-    public void testApexModelVaidateWarning() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateWarning();
-        assertEquals(WARNING_MODEL_STRING, result.toString());
+    void testApexModelValidateWarning() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateWarning();
+        var expectedResult = ResourceUtils.getResourceAsString(WARNING_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelVaidateInvalidModel() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateInvalidModel();
-        assertEquals(INVALID_MODEL_STRING, result.toString());
+    void testModelValidateInvalidModel() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateInvalidModel();
+        var expectedResult = ResourceUtils.getResourceAsString(INVALID_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelVaidateMalstructured() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateMalstructured();
-        assertEquals(INVALID_MODEL_MALSTRUCTURED_STRING, result.toString());
+    void testModelValidateMalstructured() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateMalstructured();
+        var expectedResult = ResourceUtils.getResourceAsString(INVALID_MODEL_MALSTRUCTURED_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelWriteReadJson() throws Exception {
+    void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportBasicModelTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportBasicModelTest.java
index d55a9da29..17a7f451e 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportBasicModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportBasicModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020-2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020-2022, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,33 +23,33 @@ package org.onap.policy.apex.model.basicmodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 
-public class SupportBasicModelTest {
+class SupportBasicModelTest {
 
     @Test
-    public void testNormalModelCreator() throws ApexException {
-        final TestApexModel<AxModel> testApexModel = new TestApexModel<AxModel>(AxModel.class,
+    void testNormalModelCreator() throws ApexException {
+        final TestApexModel<AxModel> testApexModel = new TestApexModel<>(AxModel.class,
             new DummyApexBasicModelCreator());
 
         testApexModel.testApexModelValid();
-        assertThatThrownBy(testApexModel::testApexModelVaidateObservation)
+        assertThatThrownBy(testApexModel::testApexModelValidateObservation)
             .hasMessage("model should have observations");
-        testApexModel.testApexModelVaidateWarning();
-        testApexModel.testApexModelVaidateInvalidModel();
-        testApexModel.testApexModelVaidateMalstructured();
+        testApexModel.testApexModelValidateWarning();
+        testApexModel.testApexModelValidateInvalidModel();
+        testApexModel.testApexModelValidateMalstructured();
 
         testApexModel.testApexModelWriteReadJson();
     }
 
     @Test
-    public void testModelsUnequal() throws ApexException {
-        final TestApexModel<AxModel> testApexModel0 = new TestApexModel<AxModel>(AxModel.class,
+    void testModelsUnequal() {
+        final TestApexModel<AxModel> testApexModel0 = new TestApexModel<>(AxModel.class,
             new DummyApexBasicModelCreator());
-        final TestApexModel<AxModel> testApexModel1 = new TestApexModel<AxModel>(AxModel.class,
+        final TestApexModel<AxModel> testApexModel1 = new TestApexModel<>(AxModel.class,
             new DummyApexBasicModelCreator());
 
         testApexModel1.getModel().getKey().setVersion("0.0.2");
@@ -59,53 +59,53 @@ public class SupportBasicModelTest {
     }
 
     @Test
-    public void testModelCreator0() throws ApexException {
-        final TestApexModel<AxModel> testApexModel = new TestApexModel<AxModel>(AxModel.class,
+    void testModelCreator0() throws ApexException {
+        final TestApexModel<AxModel> testApexModel = new TestApexModel<>(AxModel.class,
             new SupportApexModelCreator0());
 
         testApexModel.testApexModelValid();
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateObservation())
+        assertThatThrownBy(testApexModel::testApexModelValidateObservation)
             .hasMessage("model should have observations");
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateWarning())
+        assertThatThrownBy(testApexModel::testApexModelValidateWarning)
             .hasMessage("model should have warnings");
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateInvalidModel())
+        assertThatThrownBy(testApexModel::testApexModelValidateInvalidModel)
             .hasMessage("model should not be valid ***validation of model successful***");
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateMalstructured())
+        assertThatThrownBy(testApexModel::testApexModelValidateMalstructured)
             .hasMessage("model should not be valid ***validation of model successful***");
     }
 
     @Test
-    public void testModelCreator1() throws ApexException {
+    void testModelCreator1() throws ApexException {
         final TestApexModel<AxModel> testApexModel = new TestApexModel<AxModel>(AxModel.class,
             new SupportApexModelCreator1());
 
-        assertThatThrownBy(() -> testApexModel.testApexModelValid())
+        assertThatThrownBy(testApexModel::testApexModelValid)
             .hasMessageStartingWith("model is invalid");
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateObservation())
+        assertThatThrownBy(testApexModel::testApexModelValidateObservation)
             .hasMessageStartingWith("model is invalid");
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateWarning())
+        assertThatThrownBy(testApexModel::testApexModelValidateWarning)
             .hasMessageStartingWith("model is invalid");
-        testApexModel.testApexModelVaidateInvalidModel();
-        testApexModel.testApexModelVaidateMalstructured();
+        testApexModel.testApexModelValidateInvalidModel();
+        testApexModel.testApexModelValidateMalstructured();
     }
 
     @Test
-    public void testModelCreator2() throws ApexException {
-        final TestApexModel<AxModel> testApexModel = new TestApexModel<AxModel>(AxModel.class,
+    void testModelCreator2() throws ApexException {
+        final TestApexModel<AxModel> testApexModel = new TestApexModel<>(AxModel.class,
             new SupportApexModelCreator2());
 
         testApexModel.testApexModelValid();
-        testApexModel.testApexModelVaidateObservation();
-        assertThatThrownBy(() -> testApexModel.testApexModelVaidateWarning())
+        testApexModel.testApexModelValidateObservation();
+        assertThatThrownBy(testApexModel::testApexModelValidateWarning)
             .hasMessage("model should have warnings");
     }
 
     @Test
-    public void testModelCreator1Json() throws ApexException {
-        final TestApexModel<AxModel> testApexModel = new TestApexModel<AxModel>(AxModel.class,
+    void testModelCreator1Json() {
+        final TestApexModel<AxModel> testApexModel = new TestApexModel<>(AxModel.class,
             new SupportApexModelCreator1());
 
-        assertThatThrownBy(() -> testApexModel.testApexModelWriteReadJson())
+        assertThatThrownBy(testApexModel::testApexModelWriteReadJson)
             .hasMessageStartingWith("error processing file");
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportConceptGetterTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportConceptGetterTest.java
index 1783fc00f..9d83ed84c 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportConceptGetterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/handling/SupportConceptGetterTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020-2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020-2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,21 +21,22 @@
 
 package org.onap.policy.apex.model.basicmodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.util.UUID;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo;
 import org.onap.policy.apex.model.basicmodel.concepts.AxModel;
 
-public class SupportConceptGetterTest {
+class SupportConceptGetterTest {
 
     private static final AxKeyInfo intKI01 = new AxKeyInfo(new AxArtifactKey("IntegerKIKey01", "0.0.1"),
             UUID.randomUUID(), "IntegerKIKey01 description");
@@ -109,7 +110,7 @@ public class SupportConceptGetterTest {
             UUID.randomUUID(), "IntegerKIKey93 description");
 
     @Test
-    public void testConceptGetterInteger() {
+    void testConceptGetterInteger() {
         AxModel basicModel = setTestBasicModel();
 
         assertNull(basicModel.getKeyInformation().get("NonExistantKey", "0.0.6"));
@@ -133,7 +134,7 @@ public class SupportConceptGetterTest {
     }
 
     @Test
-    public void testConceptGetterFloat() {
+    void testConceptGetterFloat() {
         AxModel basicModel = setTestBasicModel();
 
         assertEquals(floatKI01, basicModel.getKeyInformation().get("FloatKIKey01"));
@@ -149,12 +150,12 @@ public class SupportConceptGetterTest {
     }
 
     @Test
-    public void testMarshalling() throws IOException, ApexException {
+    void testMarshalling() throws IOException, ApexException {
         AxModel basicModel = setTestBasicModel();
 
         // Ensure marshalling and unmarshalling is OK
-        ApexModelReader<AxModel> modelReader = new ApexModelReader<AxModel>(AxModel.class);
-        ApexModelFileWriter<AxModel> modelWriter = new ApexModelFileWriter<AxModel>(true);
+        ApexModelReader<AxModel> modelReader = new ApexModelReader<>(AxModel.class);
+        ApexModelFileWriter<AxModel> modelWriter = new ApexModelFileWriter<>(true);
 
         modelReader.setValidate(false);
         modelWriter.setValidate(false);
@@ -168,7 +169,7 @@ public class SupportConceptGetterTest {
         assertEquals(basicModel, readJsonModel);
         assertEquals(intKI91, readJsonModel.getKeyInformation().get("IntegerKIKey91"));
         assertNotNull(readJsonModel.getKeyInformation().get("FloatKIKey"));
-        tempJsonFile.delete();
+        assertTrue(tempJsonFile.delete());
     }
 
     private AxModel setTestBasicModel() {
diff --git a/model/src/test/java/org/onap/policy/apex/model/basicmodel/service/ModelServiceTest.java b/model/src/test/java/org/onap/policy/apex/model/basicmodel/service/ModelServiceTest.java
index 746e10607..7c2aa9faf 100644
--- a/model/src/test/java/org/onap/policy/apex/model/basicmodel/service/ModelServiceTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/basicmodel/service/ModelServiceTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,26 +22,26 @@
 package org.onap.policy.apex.model.basicmodel.service;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
 import org.onap.policy.apex.model.basicmodel.handling.DummyApexBasicModelCreator;
 
-public class ModelServiceTest {
+class ModelServiceTest {
 
     @Test
-    public void testModelService() {
+    void testModelService() {
         ModelService.clear();
 
         assertFalse(ModelService.existsModel(AxKeyInformation.class));
         assertThatThrownBy(() -> ModelService.getModel(AxKeyInformation.class))
             .hasMessage("Model for org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation "
-                            + "not found in model service");
+                + "not found in model service");
         ModelService.registerModel(AxKeyInformation.class,
-                        new DummyApexBasicModelCreator().getModel().getKeyInformation());
+            new DummyApexBasicModelCreator().getModel().getKeyInformation());
         assertTrue(ModelService.existsModel(AxKeyInformation.class));
         assertNotNull(ModelService.getModel(AxKeyInformation.class));
 
@@ -50,9 +50,9 @@ public class ModelServiceTest {
         assertFalse(ModelService.existsModel(AxKeyInformation.class));
         assertThatThrownBy(() -> ModelService.getModel(AxKeyInformation.class))
             .hasMessage("Model for org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation "
-                            + "not found in model service");
+                + "not found in model service");
         ModelService.registerModel(AxKeyInformation.class,
-                        new DummyApexBasicModelCreator().getModel().getKeyInformation());
+            new DummyApexBasicModelCreator().getModel().getKeyInformation());
         assertTrue(ModelService.existsModel(AxKeyInformation.class));
         assertNotNull(ModelService.getModel(AxKeyInformation.class));
 
@@ -60,6 +60,6 @@ public class ModelServiceTest {
         assertFalse(ModelService.existsModel(AxKeyInformation.class));
         assertThatThrownBy(() -> ModelService.getModel(AxKeyInformation.class))
             .hasMessage("Model for org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation "
-                            + "not found in model service");
+                + "not found in model service");
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextAlbumsTest.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextAlbumsTest.java
index 44161b329..ab1275c96 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextAlbumsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextAlbumsTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2021 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2021, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -24,11 +24,13 @@ package org.onap.policy.apex.model.contextmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.ValidationResult;
@@ -38,17 +40,17 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ContextAlbumsTest {
+class ContextAlbumsTest {
 
     @Test
-    public void testNewAxContectAlbum() {
+    void testNewAxContextAlbum() {
         assertNotNull(new AxContextAlbum());
         assertNotNull(new AxContextAlbum(new AxArtifactKey()));
         assertNotNull(new AxContextAlbum(new AxArtifactKey(), "AlbumScope", false, new AxArtifactKey()));
     }
 
     @Test
-    public void testContextAlbums() {
+    void testContextAlbums() {
         final AxArtifactKey albumKey = new AxArtifactKey("AlbumName", "0.0.1");
         final AxArtifactKey albumSchemaKey = new AxArtifactKey("AlbumSchemaName", "0.0.1");
 
@@ -63,14 +65,14 @@ public class ContextAlbumsTest {
 
         assertThatThrownBy(() -> album.setScope(""))
             .hasMessage("parameter \"scope\": value \"\", does not match regular expression "
-                    + "\"[A-Za-z0-9\\-_]+\"");
+                + "\"[A-Za-z0-9\\-_]+\"");
 
         album.setScope("NewAlbumScope");
         assertEquals("NewAlbumScope", album.getScope());
 
-        assertEquals(false, album.isWritable());
+        assertFalse(album.isWritable());
         album.setWritable(true);
-        assertEquals(true, album.isWritable());
+        assertTrue(album.isWritable());
 
         final AxArtifactKey newSchemaKey = new AxArtifactKey("NewAlbumSchemaName", "0.0.1");
         album.setItemSchema(newSchemaKey);
@@ -91,7 +93,7 @@ public class ContextAlbumsTest {
     }
 
     @Test
-    public void testAxvalidationAlbum() {
+    void testAxValidationAlbum() {
         final AxContextAlbum album = setTestAlbum();
         AxValidationResult result = new AxValidationResult();
         result = album.validate(result);
@@ -132,7 +134,7 @@ public class ContextAlbumsTest {
     }
 
     @Test
-    public void testEqualsAlbum() {
+    void testEqualsAlbum() {
         final AxContextAlbum album = setTestAlbum();
         final AxArtifactKey newKey = new AxArtifactKey("NewAlbumName", "0.0.1");
         final AxArtifactKey albumSchemaKey = new AxArtifactKey("AlbumSchemaName", "0.0.1");
@@ -140,8 +142,8 @@ public class ContextAlbumsTest {
 
         final AxContextAlbum clonedAlbum = new AxContextAlbum(album);
         assertEquals("AxContextAlbum(key=AxArtifactKey:(name=NewAlbumName,version=0.0.1), "
-                        + "scope=NewAlbumScope, isWritable=true, itemSchema="
-                        + "AxArtifactKey:(name=AlbumSchemaName,version=0.0.1))", clonedAlbum.toString());
+            + "scope=NewAlbumScope, isWritable=true, itemSchema="
+            + "AxArtifactKey:(name=AlbumSchemaName,version=0.0.1))", clonedAlbum.toString());
 
         assertNotEquals(0, album.hashCode());
         // disabling sonar because this code tests the equals() method
@@ -160,17 +162,17 @@ public class ContextAlbumsTest {
         assertNotEquals(0, album.compareTo(null));
         assertNotEquals(0, album.compareTo(new AxArtifactKey()));
         assertNotEquals(0, album.compareTo(
-                        new AxContextAlbum(new AxArtifactKey(), "Scope", false, AxArtifactKey.getNullKey())));
+            new AxContextAlbum(new AxArtifactKey(), "Scope", false, AxArtifactKey.getNullKey())));
         assertNotEquals(0, album.compareTo(new AxContextAlbum(newKey, "Scope", false, AxArtifactKey.getNullKey())));
         assertNotEquals(0, album
-                        .compareTo(new AxContextAlbum(newKey, "NewAlbumScope", false, AxArtifactKey.getNullKey())));
+            .compareTo(new AxContextAlbum(newKey, "NewAlbumScope", false, AxArtifactKey.getNullKey())));
         assertNotEquals(0,
-                        album.compareTo(new AxContextAlbum(newKey, "NewAlbumScope", true, AxArtifactKey.getNullKey())));
+            album.compareTo(new AxContextAlbum(newKey, "NewAlbumScope", true, AxArtifactKey.getNullKey())));
         assertEquals(0, album.compareTo(new AxContextAlbum(newKey, "NewAlbumScope", true, albumSchemaKey)));
     }
 
     @Test
-    public void testMultipleAlbums() {
+    void testMultipleAlbums() {
         final AxContextAlbums albums = new AxContextAlbums();
         final AxContextAlbum album = setTestAlbum();
         final AxArtifactKey newKey = new AxArtifactKey("NewAlbumName", "0.0.1");
@@ -212,7 +214,7 @@ public class ContextAlbumsTest {
     }
 
     @Test
-    public void testClonedAlbums() {
+    void testClonedAlbums() {
         final AxContextAlbums albums = new AxContextAlbums();
         final AxContextAlbum album = setTestAlbum();
         final AxArtifactKey newKey = new AxArtifactKey("NewAlbumName", "0.0.1");
@@ -222,7 +224,7 @@ public class ContextAlbumsTest {
 
         final AxContextAlbums clonedAlbums = new AxContextAlbums(albums);
         assertThat(clonedAlbums.toString()).startsWith(
-                        "AxContextAlbums(key=AxArtifactKey:(name=AlbumsKey,version=0.0.1)");
+            "AxContextAlbums(key=AxArtifactKey:(name=AlbumsKey,version=0.0.1)");
 
         assertNotEquals(0, albums.hashCode());
 
@@ -243,6 +245,6 @@ public class ContextAlbumsTest {
         assertEquals("NewAlbumName", albums.get("NewAlbumName").getKey().getName());
         assertEquals("NewAlbumName", albums.get("NewAlbumName", "0.0.1").getKey().getName());
         assertEquals(1, albums.getAll("NewAlbumName", "0.0.1").size());
-        assertEquals(0, albums.getAll("NonExistantAlbumName").size());
+        assertEquals(0, albums.getAll("NonExistentAlbumName").size());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextModelTest.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextModelTest.java
index b148ef6be..14d80381d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,11 +23,11 @@
 package org.onap.policy.apex.model.contextmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
 
@@ -36,22 +36,22 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ContextModelTest {
+class ContextModelTest {
 
     @Test
-    public void test() {
+    void test() {
         assertNotNull(new AxContextModel());
         assertNotNull(new AxContextModel(new AxArtifactKey()));
         assertNotNull(new AxContextModel(new AxArtifactKey(), new AxContextSchemas(), new AxKeyInformation()));
         assertNotNull(new AxContextModel(new AxArtifactKey(), new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation()));
+            new AxKeyInformation()));
 
         final AxArtifactKey modelKey = new AxArtifactKey("ModelKey", "0.0.1");
         final AxArtifactKey schemasKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxArtifactKey albumsKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxArtifactKey keyInfoKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxContextModel model = new AxContextModel(modelKey, new AxContextSchemas(schemasKey),
-                        new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey));
+            new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey));
         model.register();
 
         model.clean();
@@ -68,28 +68,28 @@ public class ContextModelTest {
         assertNotEquals(model, (Object) "Hello");
         assertNotEquals(model, new AxContextModel(new AxArtifactKey()));
         assertNotEquals(model, new AxContextModel(new AxArtifactKey(), new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation()));
+            new AxKeyInformation()));
         assertNotEquals(model, new AxContextModel(modelKey, new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation()));
+            new AxKeyInformation()));
         assertNotEquals(model, new AxContextModel(modelKey, new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation(keyInfoKey)));
+            new AxKeyInformation(keyInfoKey)));
         assertNotEquals(model, new AxContextModel(modelKey, new AxContextSchemas(schemasKey), new AxContextAlbums(),
-                        new AxKeyInformation(keyInfoKey)));
+            new AxKeyInformation(keyInfoKey)));
         assertEquals(model, new AxContextModel(modelKey, new AxContextSchemas(schemasKey),
-                        new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey)));
+            new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey)));
 
         assertEquals(0, model.compareTo(model));
         assertEquals(0, model.compareTo(clonedModel));
         assertNotEquals(0, model.compareTo(new AxArtifactKey()));
         assertNotEquals(0, model.compareTo(new AxContextModel(new AxArtifactKey(), new AxContextSchemas(),
-                        new AxContextAlbums(), new AxKeyInformation())));
+            new AxContextAlbums(), new AxKeyInformation())));
         assertNotEquals(0, model.compareTo(new AxContextModel(modelKey, new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation())));
+            new AxKeyInformation())));
         assertNotEquals(0, model.compareTo(new AxContextModel(modelKey, new AxContextSchemas(), new AxContextAlbums(),
-                        new AxKeyInformation(keyInfoKey))));
+            new AxKeyInformation(keyInfoKey))));
         assertNotEquals(0, model.compareTo(new AxContextModel(modelKey, new AxContextSchemas(schemasKey),
-                        new AxContextAlbums(), new AxKeyInformation(keyInfoKey))));
+            new AxContextAlbums(), new AxKeyInformation(keyInfoKey))));
         assertEquals(0, model.compareTo(new AxContextModel(modelKey, new AxContextSchemas(schemasKey),
-                        new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey))));
+            new AxContextAlbums(albumsKey), new AxKeyInformation(keyInfoKey))));
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextSchemasTest.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextSchemasTest.java
index 52cca14bf..67edd953a 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextSchemasTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/concepts/ContextSchemasTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020-2021 Nordix Foundation.
+ *  Modifications Copyright (C) 2020-2021, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -24,11 +24,11 @@ package org.onap.policy.apex.model.contextmodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.ValidationResult;
@@ -36,19 +36,19 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
 /**
  * Context schema tests.
  */
-public class ContextSchemasTest {
+class ContextSchemasTest {
 
     @Test
-    public void testNewAxContextSchema() {
+    void testNewAxContextSchema() {
         assertNotNull(new AxContextSchema());
         assertNotNull(new AxContextSchema(new AxArtifactKey(), "SchemaFlavour", "SchemaDefinition"));
 
     }
 
     @Test
-    public void testContextSchemas() {
+    void testContextSchemas() {
         final AxContextSchema schema = new AxContextSchema(new AxArtifactKey("SchemaName", "0.0.1"), "SchemaFlavour",
-                        "SchemaDefinition");
+            "SchemaDefinition");
         assertNotNull(schema);
 
         final AxArtifactKey newKey = new AxArtifactKey("NewSchemaName", "0.0.1");
@@ -58,7 +58,7 @@ public class ContextSchemasTest {
 
         assertThatThrownBy(() -> schema.setSchemaFlavour(""))
             .hasMessage("parameter \"schemaFlavour\": value \"\", "
-                            + "does not match regular expression \"[A-Za-z0-9\\-_]+\"");
+                + "does not match regular expression \"[A-Za-z0-9\\-_]+\"");
         schema.setSchemaFlavour("NewSchemaFlavour");
         assertEquals("NewSchemaFlavour", schema.getSchemaFlavour());
 
@@ -68,7 +68,7 @@ public class ContextSchemasTest {
 
     private AxContextSchema setTestSchema() {
         final AxContextSchema schema = new AxContextSchema(new AxArtifactKey("SchemaName", "0.0.1"), "SchemaFlavour",
-                "SchemaDefinition");
+            "SchemaDefinition");
         final AxArtifactKey newKey = new AxArtifactKey("NewSchemaName", "0.0.1");
         schema.setKey(newKey);
         schema.setSchemaFlavour("NewSchemaFlavour");
@@ -78,7 +78,7 @@ public class ContextSchemasTest {
     }
 
     @Test
-    public void testAxvalidationSchema() {
+    void testAxvalidationSchema() {
         AxContextSchema schema = setTestSchema();
         AxValidationResult result = new AxValidationResult();
         result = schema.validate(result);
@@ -117,14 +117,14 @@ public class ContextSchemasTest {
     }
 
     @Test
-    public void testEqualsSchema() {
+    void testEqualsSchema() {
         AxContextSchema schema = setTestSchema();
         schema.clean();
 
         final AxContextSchema clonedSchema = new AxContextSchema(schema);
         assertEquals("AxContextSchema(key=AxArtifactKey:(name=NewSchemaName,version=0.0.1), "
-                        + "schemaFlavour=NewSchemaFlavour, schemaDefinition=NewSchemaDefinition)",
-                        clonedSchema.toString());
+                + "schemaFlavour=NewSchemaFlavour, schemaDefinition=NewSchemaDefinition)",
+            clonedSchema.toString());
 
         assertNotEquals(0, schema.hashCode());
 
@@ -151,7 +151,7 @@ public class ContextSchemasTest {
     }
 
     @Test
-    public void testMultipleSchemas() {
+    void testMultipleSchemas() {
         final AxContextSchemas schemas = new AxContextSchemas();
         AxValidationResult result = new AxValidationResult();
         result = schemas.validate(result);
@@ -193,7 +193,7 @@ public class ContextSchemasTest {
     }
 
     @Test
-    public void testClonedSchemas() {
+    void testClonedSchemas() {
         final AxContextSchemas schemas = new AxContextSchemas();
         AxContextSchema schema = setTestSchema();
         final AxArtifactKey newKey = new AxArtifactKey("NewSchemaName", "0.0.1");
@@ -203,7 +203,7 @@ public class ContextSchemasTest {
 
         final AxContextSchemas clonedSchemas = new AxContextSchemas(schemas);
         assertThat(clonedSchemas.toString())
-                        .startsWith("AxContextSchemas(key=AxArtifactKey:(name=SchemasKey,version=0.0.1),");
+            .startsWith("AxContextSchemas(key=AxArtifactKey:(name=SchemasKey,version=0.0.1),");
 
         assertNotEquals(0, schemas.hashCode());
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ApexContextModelTest.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ApexContextModelTest.java
index 998469bac..a9cb16914 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ApexContextModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ApexContextModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,104 +21,80 @@
 
 package org.onap.policy.apex.model.contextmodel.handling;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextModel;
+import org.onap.policy.common.utils.resources.ResourceUtils;
 
 /**
  * Apex context model tests.
  *
  * @author liam
- *
  */
-public class ApexContextModelTest {
+class ApexContextModelTest {
 
     private static final String VALID_MODEL_STRING = "***validation of model successful***";
 
-    private static final String OBSERVATION_MODEL_STRING = "\n"
-                    + "***observations noted during validation of model***\n"
-                    + "AxArtifactKey:(name=contextAlbum1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:OBSERVATION:description is blank\n"
-                    + "********************************";
-
-    private static final String WARNING_MODEL_STRING = "\n" + "***warnings issued during validation of model***\n"
-                    + "AxArtifactKey:(name=contextAlbum1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:WARNING:"
-                    + "UUID is a zero UUID: 00000000-0000-0000-0000-000000000000\n"
-                    + "********************************";
-
-    private static final String INVALID_MODEL_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=StringType,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema:INVALID:"
-                    + "no schemaDefinition specified, schemaDefinition may not be blank\n"
-                    + "AxArtifactKey:(name=contextAlbum0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:"
-                    + "scope is not defined\n" + "********************************";
-
-    private static final String INVALID_MODEL_MALSTRUCTURED_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=ContextModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=contextAlbum1,version=0.0.2)\n"
-                    + "AxArtifactKey:(name=contextAlbum1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextModel:WARNING:"
-                    + "key not found for key information entry\n" + "AxArtifactKey:(name=ContextSchemas,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas:INVALID:"
-                    + "key on schemas entry AxArtifactKey:(name=MapType,version=0.0.1) "
-                    + "does not equal entry key AxArtifactKey:(name=MapType,version=0.0.2)\n"
-                    + "AxArtifactKey:(name=contextAlbums,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbums:INVALID:"
-                    + "key on context album entry key AxArtifactKey:(name=contextAlbum1,version=0.0.1) "
-                    + "does not equal context album value key AxArtifactKey:(name=contextAlbum1,version=0.0.2)\n"
-                    + "********************************";
+    private static final String OBSERVATION_MODEL_STRING =
+        "contextmodel/handling/ApexContextModel_ObservationModel.txt";
+
+    private static final String WARNING_MODEL_STRING = "contextmodel/handling/ApexContextModel_WarningModel.txt";
+
+    private static final String INVALID_MODEL_STRING = "contextmodel/handling/ApexContextModel_InvalidModel.txt";
+
+    private static final String INVALID_MODEL_MALSTRUCTURED_STRING =
+        "contextmodel/handling/ApexContextModel_InvalidMalStructuredModel.txt";
 
     TestApexModel<AxContextModel> testApexModel;
 
     /**
      * Set up tests.
-     *
-     * @throws Exception a testing exception
      */
-    @Before
-    public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxContextModel>(AxContextModel.class, new TestApexContextModelCreator());
+    @BeforeEach
+    void setup() {
+        testApexModel = new TestApexModel<>(AxContextModel.class, new TestApexContextModelCreator());
     }
 
     @Test
-    public void testModelValid() throws Exception {
+    void testModelValid() throws Exception {
         final AxValidationResult result = testApexModel.testApexModelValid();
         assertEquals(VALID_MODEL_STRING, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateObservation() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateObservation();
-        assertEquals(OBSERVATION_MODEL_STRING, result.toString());
+    void testApexModelValidateObservation() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateObservation();
+        var expectedResult = ResourceUtils.getResourceAsString(OBSERVATION_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateWarning() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateWarning();
-        assertEquals(WARNING_MODEL_STRING, result.toString());
+    void testApexModelValidateWarning() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateWarning();
+        var expectedResult = ResourceUtils.getResourceAsString(WARNING_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelVaidateInvalidModel() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateInvalidModel();
-        assertEquals(INVALID_MODEL_STRING, result.toString());
+    void testModelValidateInvalidModel() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateInvalidModel();
+        var expectedResult = ResourceUtils.getResourceAsString(INVALID_MODEL_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelVaidateMalstructured() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateMalstructured();
-        assertEquals(INVALID_MODEL_MALSTRUCTURED_STRING, result.toString());
+    void testModelValidateMalstructured() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateMalstructured();
+        var expectedResult = ResourceUtils.getResourceAsString(INVALID_MODEL_MALSTRUCTURED_STRING);
+        assertEquals(expectedResult, result.toString());
     }
 
     @Test
-    public void testModelWriteReadJson() throws Exception {
+    void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ContextComparisonTest.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ContextComparisonTest.java
index 483bc3661..b898122ae 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ContextComparisonTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/ContextComparisonTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,11 +21,11 @@
 
 package org.onap.policy.apex.model.contextmodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextModel;
@@ -37,7 +37,7 @@ import org.onap.policy.apex.model.utilities.comparison.KeyedMapDifference;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ContextComparisonTest {
+class ContextComparisonTest {
     private AxContextModel emptyModel;
     private AxContextModel fullModel;
     private AxContextModel noGlobalContextModel;
@@ -47,8 +47,8 @@ public class ContextComparisonTest {
     /**
      * Set up tests.
      */
-    @Before
-    public void getContext() {
+    @BeforeEach
+    void getContext() {
         final TestContextComparisonFactory factory = new TestContextComparisonFactory();
         emptyModel = factory.getEmptyModel();
         fullModel = factory.getFullModel();
@@ -58,131 +58,131 @@ public class ContextComparisonTest {
     }
 
     @Test
-    public void testEmptyEmpty() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(emptyModel.getSchemas(), emptyModel.getSchemas());
+    void testEmptyEmpty() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(emptyModel.getSchemas(), emptyModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(emptyModel.getSchemas().getSchemasMap(), schemaResult.getIdenticalValues());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(emptyModel.getAlbums(), emptyModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(emptyModel.getAlbums(), emptyModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(emptyModel.getAlbums().getAlbumsMap(), albumResult.getIdenticalValues());
     }
 
     @Test
-    public void testEmptyFull() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(emptyModel.getSchemas(), fullModel.getSchemas());
+    void testEmptyFull() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(emptyModel.getSchemas(), fullModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(fullModel.getSchemas().getSchemasMap(), schemaResult.getRightOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(emptyModel.getAlbums(), fullModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(emptyModel.getAlbums(), fullModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(fullModel.getAlbums().getAlbumsMap(), albumResult.getRightOnly());
     }
 
     @Test
-    public void testFullEmpty() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(fullModel.getSchemas(), emptyModel.getSchemas());
+    void testFullEmpty() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(fullModel.getSchemas(), emptyModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(fullModel.getSchemas().getSchemasMap(), schemaResult.getLeftOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(fullModel.getAlbums(), emptyModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(fullModel.getAlbums(), emptyModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(fullModel.getAlbums().getAlbumsMap(), albumResult.getLeftOnly());
     }
 
     @Test
-    public void testEmptyNoGlobalContext() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(emptyModel.getSchemas(), noGlobalContextModel.getSchemas());
+    void testEmptyNoGlobalContext() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(emptyModel.getSchemas(), noGlobalContextModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(noGlobalContextModel.getSchemas().getSchemasMap(), schemaResult.getRightOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(emptyModel.getAlbums(), noGlobalContextModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(emptyModel.getAlbums(), noGlobalContextModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(noGlobalContextModel.getAlbums().getAlbumsMap(), albumResult.getRightOnly());
     }
 
     @Test
-    public void testNoGlobalContextEmpty() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(noGlobalContextModel.getSchemas(), emptyModel.getSchemas());
+    void testNoGlobalContextEmpty() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(noGlobalContextModel.getSchemas(), emptyModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(noGlobalContextModel.getSchemas().getSchemasMap(), schemaResult.getLeftOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(noGlobalContextModel.getAlbums(), emptyModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(noGlobalContextModel.getAlbums(), emptyModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(noGlobalContextModel.getAlbums().getAlbumsMap(), albumResult.getLeftOnly());
     }
 
     @Test
-    public void testEmptyShell() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(emptyModel.getSchemas(), shellModel.getSchemas());
+    void testEmptyShell() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(emptyModel.getSchemas(), shellModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(shellModel.getSchemas().getSchemasMap(), schemaResult.getRightOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(emptyModel.getAlbums(), shellModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(emptyModel.getAlbums(), shellModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(shellModel.getAlbums().getAlbumsMap(), albumResult.getRightOnly());
     }
 
     @Test
-    public void testShellEmpty() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(shellModel.getSchemas(), emptyModel.getSchemas());
+    void testShellEmpty() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(shellModel.getSchemas(), emptyModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(shellModel.getSchemas().getSchemasMap(), schemaResult.getLeftOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(shellModel.getAlbums(), emptyModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(shellModel.getAlbums(), emptyModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(shellModel.getAlbums().getAlbumsMap(), albumResult.getLeftOnly());
     }
 
     @Test
-    public void testEmptySingleEntry() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(emptyModel.getSchemas(), singleEntryModel.getSchemas());
+    void testEmptySingleEntry() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(emptyModel.getSchemas(), singleEntryModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(singleEntryModel.getSchemas().getSchemasMap(), schemaResult.getRightOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(emptyModel.getAlbums(), singleEntryModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(emptyModel.getAlbums(), singleEntryModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(singleEntryModel.getAlbums().getAlbumsMap(), albumResult.getRightOnly());
     }
 
     @Test
-    public void testSingleEntryEmpty() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(singleEntryModel.getSchemas(), emptyModel.getSchemas());
+    void testSingleEntryEmpty() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(singleEntryModel.getSchemas(), emptyModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(singleEntryModel.getSchemas().getSchemasMap(), schemaResult.getLeftOnly());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(singleEntryModel.getAlbums(), emptyModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(singleEntryModel.getAlbums(), emptyModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(singleEntryModel.getAlbums().getAlbumsMap(), albumResult.getLeftOnly());
     }
 
     @Test
-    public void testFullFull() {
-        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult = new ContextComparer()
-                        .compare(fullModel.getSchemas(), fullModel.getSchemas());
+    void testFullFull() {
+        final KeyedMapDifference<AxArtifactKey, AxContextSchema> schemaResult =
+            new ContextComparer().compare(fullModel.getSchemas(), fullModel.getSchemas());
         assertNotNull(schemaResult);
         assertEquals(fullModel.getSchemas().getSchemasMap(), schemaResult.getIdenticalValues());
 
-        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult = new ContextComparer()
-                        .compare(fullModel.getAlbums(), fullModel.getAlbums());
+        final KeyedMapDifference<AxArtifactKey, AxContextAlbum> albumResult =
+            new ContextComparer().compare(fullModel.getAlbums(), fullModel.getAlbums());
         assertNotNull(albumResult);
         assertEquals(fullModel.getAlbums().getAlbumsMap(), albumResult.getIdenticalValues());
     }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestApexContextModelCreator.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestApexContextModelCreator.java
index 3fe7e3aa2..8d366981d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestApexContextModelCreator.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestApexContextModelCreator.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,18 +37,18 @@ public class TestApexContextModelCreator implements TestApexModelCreator<AxConte
     @Override
     public AxContextModel getModel() {
         final AxContextSchema schema0 = new AxContextSchema(new AxArtifactKey("StringType", "0.0.1"), "Java",
-                "org.onap.policy.apex.concept.TestContextItem000");
+            "org.onap.policy.apex.concept.TestContextItem000");
         final AxContextSchema schema1 = new AxContextSchema(new AxArtifactKey("MapType", "0.0.1"), "Java",
-                "org.onap.policy.apex.concept.TestContextItem00A");
+            "org.onap.policy.apex.concept.TestContextItem00A");
 
         final AxContextSchemas contextSchemas = new AxContextSchemas(new AxArtifactKey("ContextSchemas", "0.0.1"));
         contextSchemas.getSchemasMap().put(schema0.getKey(), schema0);
         contextSchemas.getSchemasMap().put(schema1.getKey(), schema1);
 
         final AxContextAlbum contextAlbum0 =
-                new AxContextAlbum(new AxArtifactKey("contextAlbum0", "0.0.1"), "APPLICATION", true, schema0.getKey());
+            new AxContextAlbum(new AxArtifactKey("contextAlbum0", "0.0.1"), "APPLICATION", true, schema0.getKey());
         final AxContextAlbum contextAlbum1 =
-                new AxContextAlbum(new AxArtifactKey("contextAlbum1", "0.0.1"), "GLOBAL", false, schema1.getKey());
+            new AxContextAlbum(new AxArtifactKey("contextAlbum1", "0.0.1"), "GLOBAL", false, schema1.getKey());
 
         final AxContextAlbums axContext = new AxContextAlbums(new AxArtifactKey("contextAlbums", "0.0.1"));
         axContext.getAlbumsMap().put(contextAlbum0.getKey(), contextAlbum0);
@@ -55,25 +56,25 @@ public class TestApexContextModelCreator implements TestApexModelCreator<AxConte
 
         final AxKeyInformation keyInformation = new AxKeyInformation(new AxArtifactKey("KeyInfoMapKey", "0.0.1"));
         final AxContextModel contextModel = new AxContextModel(new AxArtifactKey("ContextModel", "0.0.1"),
-                contextSchemas, axContext, keyInformation);
+            contextSchemas, axContext, keyInformation);
 
         contextModel.setKeyInformation(keyInformation);
         contextModel.getKeyInformation().getKeyInfoMap().put(schema0.getKey(), new AxKeyInfo(schema0.getKey(),
-                UUID.fromString("00000000-0000-0000-0000-000000000001"), "axContextSchema0"));
+            UUID.fromString("00000000-0000-0000-0000-000000000001"), "axContextSchema0"));
         contextModel.getKeyInformation().getKeyInfoMap().put(schema1.getKey(), new AxKeyInfo(schema1.getKey(),
-                UUID.fromString("00000000-0000-0000-0000-000000000002"), "axContextSchema1"));
+            UUID.fromString("00000000-0000-0000-0000-000000000002"), "axContextSchema1"));
         contextModel.getKeyInformation().getKeyInfoMap().put(contextSchemas.getKey(), new AxKeyInfo(
-                contextSchemas.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000003"), "ContextSchemas"));
+            contextSchemas.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000003"), "ContextSchemas"));
         contextModel.getKeyInformation().getKeyInfoMap().put(contextAlbum0.getKey(), new AxKeyInfo(
-                contextAlbum0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000004"), "contextAlbum0"));
+            contextAlbum0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000004"), "contextAlbum0"));
         contextModel.getKeyInformation().getKeyInfoMap().put(contextAlbum1.getKey(), new AxKeyInfo(
-                contextAlbum1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000005"), "contextAlbum1"));
+            contextAlbum1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000005"), "contextAlbum1"));
         contextModel.getKeyInformation().getKeyInfoMap().put(axContext.getKey(), new AxKeyInfo(axContext.getKey(),
-                UUID.fromString("00000000-0000-0000-0000-000000000006"), "axContext"));
+            UUID.fromString("00000000-0000-0000-0000-000000000006"), "axContext"));
         contextModel.getKeyInformation().getKeyInfoMap().put(contextModel.getKey(), new AxKeyInfo(contextModel.getKey(),
-                UUID.fromString("00000000-0000-0000-0000-000000000007"), "contextModel"));
+            UUID.fromString("00000000-0000-0000-0000-000000000007"), "contextModel"));
         contextModel.getKeyInformation().getKeyInfoMap().put(keyInformation.getKey(), new AxKeyInfo(
-                keyInformation.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000008"), "keyInformation"));
+            keyInformation.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000008"), "keyInformation"));
 
         return contextModel;
     }
@@ -81,42 +82,33 @@ public class TestApexContextModelCreator implements TestApexModelCreator<AxConte
     @Override
     public AxContextModel getInvalidModel() {
         final AxContextModel contextModel = getModel();
-
         contextModel.getAlbums().get(new AxArtifactKey("contextAlbum0", "0.0.1")).setScope("UNDEFINED");
-
         contextModel.getSchemas().get(new AxArtifactKey("StringType", "0.0.1")).setSchema("");
-
         return contextModel;
     }
 
     @Override
     public AxContextModel getMalstructuredModel() {
         final AxContextModel contextModel = getModel();
-
         contextModel.getAlbums().get(new AxArtifactKey("contextAlbum1", "0.0.1"))
-                .setKey(new AxArtifactKey("contextAlbum1", "0.0.2"));;
+            .setKey(new AxArtifactKey("contextAlbum1", "0.0.2"));
         contextModel.getSchemas().get(new AxArtifactKey("MapType", "0.0.1"))
-                .setKey(new AxArtifactKey("MapType", "0.0.2"));;
-
+            .setKey(new AxArtifactKey("MapType", "0.0.2"));
         return contextModel;
     }
 
     @Override
     public AxContextModel getObservationModel() {
         final AxContextModel contextModel = getModel();
-
         contextModel.getKeyInformation().get("contextAlbum1", "0.0.1").setDescription("");
-
         return contextModel;
     }
 
     @Override
     public AxContextModel getWarningModel() {
         final AxContextModel contextModel = getModel();
-
         contextModel.getKeyInformation().get("contextAlbum1", "0.0.1")
-                .setUuid(UUID.fromString("00000000-0000-0000-0000-000000000000"));
-
+            .setUuid(UUID.fromString("00000000-0000-0000-0000-000000000000"));
         return contextModel;
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestContextComparisonFactory.java b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestContextComparisonFactory.java
index f7c7a1345..d396848b6 100644
--- a/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestContextComparisonFactory.java
+++ b/model/src/test/java/org/onap/policy/apex/model/contextmodel/handling/TestContextComparisonFactory.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,27 +35,28 @@ public class TestContextComparisonFactory {
 
     /**
      * Get a full context model.
+     *
      * @return the model
      */
     public AxContextModel getFullModel() {
         final AxContextSchema testContextSchema000 =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema000");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema000");
         final AxContextSchema testContextSchema00A =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema00A", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema00A");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema00A", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema00A");
         final AxContextSchema testContextSchema00C =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema00C");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema00C");
 
         final AxContextAlbum externalContextAlbum = new AxContextAlbum(
-                new AxArtifactKey("ExternalContextAlbum", "0.0.1"), "EXTERNAL", false, testContextSchema000.getKey());
+            new AxArtifactKey("ExternalContextAlbum", "0.0.1"), "EXTERNAL", false, testContextSchema000.getKey());
         final AxContextAlbum globalContextAlbum = new AxContextAlbum(new AxArtifactKey("GlobalContextAlbum", "0.0.1"),
-                "GLOBAL", true, testContextSchema00A.getKey());
+            "GLOBAL", true, testContextSchema00A.getKey());
         final AxContextAlbum policy0ContextAlbum = new AxContextAlbum(new AxArtifactKey("Policy0ContextAlbum", "0.0.1"),
-                "APPLICATION", true, testContextSchema00C.getKey());
+            "APPLICATION", true, testContextSchema00C.getKey());
         final AxContextAlbum policy1ContextAlbum = new AxContextAlbum(
-                new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema00C.getKey());
+            new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema00C.getKey());
 
         final AxContextModel contextModel = new AxContextModel(new AxArtifactKey("ContextModel", "0.0.1"));
         contextModel.getSchemas().getSchemasMap().put(testContextSchema000.getKey(), testContextSchema000);
@@ -75,18 +77,19 @@ public class TestContextComparisonFactory {
 
     /**
      * Get a skeleton model.
+     *
      * @return The model
      */
     public AxContextModel getShellModel() {
         final AxContextSchema testContextSchema000 =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema000");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema000");
         final AxContextSchema testContextSchema00A =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema00A", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema00A");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema00A", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema00A");
         final AxContextSchema testContextSchema00C =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema00C");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema00C");
 
         final AxContextModel contextModel = new AxContextModel(new AxArtifactKey("ContextModel", "0.0.1"));
         contextModel.getSchemas().getSchemasMap().put(testContextSchema000.getKey(), testContextSchema000);
@@ -98,15 +101,16 @@ public class TestContextComparisonFactory {
 
     /**
      * Get a single entry model.
+     *
      * @return The single entry model
      */
     public AxContextModel getSingleEntryModel() {
         final AxContextSchema testContextSchema000 =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema000");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema000");
 
         final AxContextAlbum policy1ContextAlbum = new AxContextAlbum(
-                new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema000.getKey());
+            new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema000.getKey());
 
         final AxContextModel contextModel = new AxContextModel(new AxArtifactKey("ContextModel", "0.0.1"));
         contextModel.getSchemas().getSchemasMap().put(testContextSchema000.getKey(), testContextSchema000);
@@ -118,22 +122,23 @@ public class TestContextComparisonFactory {
 
     /**
      * Get a model with no global entries.
+     *
      * @return the model
      */
     public AxContextModel getNoGlobalContextModel() {
         final AxContextSchema testContextSchema000 =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema000");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema000", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema000");
         final AxContextSchema testContextSchema00C =
-                new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
-                        "org.onap.policy.apex.concept.TestContextSchema00C");
+            new AxContextSchema(new AxArtifactKey("TestContextSchema00C", "0.0.1"), "JAVA",
+                "org.onap.policy.apex.concept.TestContextSchema00C");
 
         final AxContextAlbum externalContextAlbum = new AxContextAlbum(
-                new AxArtifactKey("ExternalContextAlbum", "0.0.1"), "EXTERNAL", false, testContextSchema000.getKey());
+            new AxArtifactKey("ExternalContextAlbum", "0.0.1"), "EXTERNAL", false, testContextSchema000.getKey());
         final AxContextAlbum policy0ContextAlbum = new AxContextAlbum(new AxArtifactKey("Policy0ContextAlbum", "0.0.1"),
-                "APPLICATION", true, testContextSchema00C.getKey());
+            "APPLICATION", true, testContextSchema00C.getKey());
         final AxContextAlbum policy1ContextAlbum = new AxContextAlbum(
-                new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema00C.getKey());
+            new AxArtifactKey("Policy1ContextAlbum ", "0.0.1"), "APPLICATION", true, testContextSchema00C.getKey());
 
         final AxContextModel contextModel = new AxContextModel(new AxArtifactKey("ContextModel", "0.0.1"));
         contextModel.getSchemas().getSchemasMap().put(testContextSchema000.getKey(), testContextSchema000);
diff --git a/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineModelTest.java b/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineModelTest.java
index c23687bb1..b9ee952c1 100644
--- a/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -24,12 +24,12 @@ package org.onap.policy.apex.model.enginemodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
@@ -40,19 +40,13 @@ import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
 
 /**
  * Test engine models.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class EngineModelTest {
+class EngineModelTest {
 
     @Test
-    public void testEnginetModel() {
-        assertNotNull(new AxEngineModel());
-        assertNotNull(new AxEngineModel(new AxArtifactKey()));
-        assertNotNull(new AxEngineModel(new AxArtifactKey(), new AxContextSchemas(), new AxKeyInformation(),
-                new AxContextAlbums()));
-        assertNotNull(new AxEngineModel(new AxArtifactKey(), new AxContextSchemas(), new AxKeyInformation(),
-                new AxContextAlbums(), AxEngineState.UNDEFINED, new AxEngineStats()));
-
+    void testEngineModel() {
         final AxArtifactKey modelKey = new AxArtifactKey("ModelName", "0.0.1");
         final AxArtifactKey schemasKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxArtifactKey albumKey = new AxArtifactKey("AlbumKey", "0.0.1");
@@ -62,11 +56,10 @@ public class EngineModelTest {
         otherStats.setAverageExecutionTime(100);
 
         final AxEngineModel model = new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats);
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats);
         model.register();
 
-        assertThatThrownBy(() -> model.setKey(null))
-            .hasMessage("key may not be null");
+        assertThatThrownBy(() -> model.setKey(null)).hasMessage("key may not be null");
         model.setKey(modelKey);
         assertEquals("ModelName:0.0.1", model.getKey().getId());
         assertEquals("ModelName:0.0.1", model.getKeys().get(0).getId());
@@ -77,8 +70,7 @@ public class EngineModelTest {
         model.setTimestamp(-1);
         assertTrue(model.getTimeStampString().matches("\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2}.\\d{3}"));
 
-        assertThatThrownBy(() -> model.setState(null))
-            .hasMessage("state may not be null");
+        assertThatThrownBy(() -> model.setState(null)).hasMessage("state may not be null");
         for (final AxEngineState state : AxEngineState.values()) {
             model.setState(state);
             assertEquals(state, model.getState());
@@ -87,8 +79,7 @@ public class EngineModelTest {
         model.setState(AxEngineState.READY);
         assertEquals(AxEngineState.READY, model.getState());
 
-        assertThatThrownBy(() -> model.setStats(null))
-            .hasMessage("stats may not be null");
+        assertThatThrownBy(() -> model.setStats(null)).hasMessage("stats may not be null");
         model.setStats(stats);
         assertEquals(stats, model.getStats());
 
@@ -101,76 +92,101 @@ public class EngineModelTest {
         assertNotEquals(0, model.hashCode());
 
         // disabling sonar because this code tests the equals() method
-        assertEquals(model, model); // NOSONAR
-        assertEquals(model, clonedModel);
-        assertNotEquals(model, (Object) "Hello");
-        assertNotEquals(model, new AxEngineModel(new AxArtifactKey()));
-        assertNotEquals(model, new AxEngineModel(new AxArtifactKey(), new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(), new AxKeyInformation(keyInfoKey),
-                new AxContextAlbums(albumKey), AxEngineState.READY, stats));
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey), new AxKeyInformation(),
-                new AxContextAlbums(albumKey), AxEngineState.READY, stats));
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(), AxEngineState.READY, stats));
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.STOPPED, stats));
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, otherStats));
-        model.setTimestamp(timestamp);
-        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
-        model.setTimestamp(0);
-        assertEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+        assertEqualsEngineModel(model, clonedModel, schemasKey, keyInfoKey, albumKey, stats, modelKey, otherStats,
+            timestamp);
 
         model.setTimestamp(-1);
         assertEquals(0, model.compareTo(model));
         assertEquals(0, model.compareTo(clonedModel));
-        assertNotEquals(0, model.compareTo(new AxArtifactKey()));
-        assertNotEquals(model, new AxEngineModel(new AxArtifactKey()));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(new AxArtifactKey(), new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(), AxEngineState.READY, stats)));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.STOPPED, stats)));
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, otherStats)));
-        model.setTimestamp(timestamp);
-        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
+        assertNotEqualsEngineModels(model, schemasKey, keyInfoKey, albumKey, stats, modelKey, otherStats, timestamp);
         model.setTimestamp(0);
         assertEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
 
-        model.setTimestamp(timestamp);
-        AxValidationResult result = new AxValidationResult();
-        result = model.validate(result);
-        assertEquals(ValidationResult.VALID, result.getValidationResult());
+        assertSetTimestampToEngineModel(model, timestamp);
 
-        model.setTimestamp(-1);
+        assertSetStateToEngineModel(model);
+    }
+
+    private static void assertSetStateToEngineModel(AxEngineModel model) {
+        AxValidationResult result;
+        model.setState(AxEngineState.UNDEFINED);
         result = new AxValidationResult();
         result = model.validate(result);
         assertEquals(ValidationResult.INVALID, result.getValidationResult());
 
-        model.setTimestamp(timestamp);
+        model.setState(AxEngineState.READY);
         result = new AxValidationResult();
         result = model.validate(result);
         assertEquals(ValidationResult.VALID, result.getValidationResult());
+    }
+
+    private static void assertSetTimestampToEngineModel(AxEngineModel model, long timestamp) {
+        model.setTimestamp(timestamp);
+        AxValidationResult result = new AxValidationResult();
+        result = model.validate(result);
+        assertEquals(ValidationResult.VALID, result.getValidationResult());
 
-        model.setState(AxEngineState.UNDEFINED);
+        model.setTimestamp(-1);
         result = new AxValidationResult();
         result = model.validate(result);
         assertEquals(ValidationResult.INVALID, result.getValidationResult());
 
-        model.setState(AxEngineState.READY);
+        model.setTimestamp(timestamp);
         result = new AxValidationResult();
         result = model.validate(result);
         assertEquals(ValidationResult.VALID, result.getValidationResult());
     }
+
+    private static void assertNotEqualsEngineModels(AxEngineModel model, AxArtifactKey schemasKey,
+                                                    AxArtifactKey keyInfoKey, AxArtifactKey albumKey,
+                                                    AxEngineStats stats, AxArtifactKey modelKey,
+                                                    AxEngineStats otherStats, long timestamp) {
+        assertNotEquals(0, model.compareTo(new AxArtifactKey()));
+        assertNotEquals(model, new AxEngineModel(new AxArtifactKey()));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(new AxArtifactKey(),
+            new AxContextSchemas(schemasKey), new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey),
+            AxEngineState.READY, stats)));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(), AxEngineState.READY, stats)));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.STOPPED, stats)));
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, otherStats)));
+        model.setTimestamp(timestamp);
+        assertNotEquals(0, model.compareTo(new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats)));
+    }
+
+    private static void assertEqualsEngineModel(AxEngineModel model, AxEngineModel clonedModel,
+                                                AxArtifactKey schemasKey,
+                                                AxArtifactKey keyInfoKey, AxArtifactKey albumKey, AxEngineStats stats,
+                                                AxArtifactKey modelKey, AxEngineStats otherStats, long timestamp) {
+        assertEquals(model, model); // NOSONAR
+        assertEquals(model, clonedModel);
+        assertNotEquals(model, (Object) "Hello");
+        assertNotEquals(model, new AxEngineModel(new AxArtifactKey()));
+        assertNotEquals(model, new AxEngineModel(new AxArtifactKey(), new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(), new AxKeyInformation(keyInfoKey),
+            new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey), new AxKeyInformation(),
+            new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(), AxEngineState.READY, stats));
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.STOPPED, stats));
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, otherStats));
+        model.setTimestamp(timestamp);
+        assertNotEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+        model.setTimestamp(0);
+        assertEquals(model, new AxEngineModel(modelKey, new AxContextSchemas(schemasKey),
+            new AxKeyInformation(keyInfoKey), new AxContextAlbums(albumKey), AxEngineState.READY, stats));
+    }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineStatsTest.java b/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineStatsTest.java
index 542c6e4c5..a9e61db62 100644
--- a/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineStatsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/enginemodel/concepts/EngineStatsTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2022 Bell Canada.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,14 +23,14 @@
 package org.onap.policy.apex.model.enginemodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
 
 import io.prometheus.client.CollectorRegistry;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -41,25 +41,61 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class EngineStatsTest {
+class EngineStatsTest {
     private static final Object WAIT_LOCK = new Object();
     private static final String ENGINE_KEY = "EngineKey";
     private static final String ENGINE_VERSION = "0.0.1";
 
     @Test
-    public void testEngineStats() {
-        assertNotNull(new AxEngineStats());
-        assertNotNull(new AxEngineStats(new AxReferenceKey()));
-
+    void testEngineStats() {
         final AxReferenceKey statsKey = new AxReferenceKey(ENGINE_KEY, ENGINE_VERSION, "EngineStats");
         final AxEngineStats stats = new AxEngineStats(statsKey);
 
-        assertThatThrownBy(() -> stats.setKey(null))
-            .hasMessage("key may not be null");
+        assertThatThrownBy(() -> stats.setKey(null)).hasMessage("key may not be null");
         stats.setKey(statsKey);
         assertEquals("EngineKey:0.0.1:NULL:EngineStats", stats.getKey().getId());
         assertEquals("EngineKey:0.0.1:NULL:EngineStats", stats.getKeys().get(0).getId());
 
+        assertSetValuesToStats(stats);
+
+        synchronized (WAIT_LOCK) {
+            try {
+                WAIT_LOCK.wait(10);
+            } catch (InterruptedException e) {
+                fail("test should not throw an exception");
+            }
+        }
+
+        stats.executionExit();
+        checkAvgExecTimeMetric(stats);
+        checkEventsCountMetric(stats);
+        checkLastExecTimeMetric(stats);
+        final double avExecutionTime = stats.getAverageExecutionTime();
+        assertTrue(avExecutionTime >= 2.0 && avExecutionTime < 10.0);
+        stats.engineStop();
+        checkEngineStartTimestampMetric(stats);
+
+        AxValidationResult result = new AxValidationResult();
+        result = stats.validate(result);
+        assertEquals(ValidationResult.VALID, result.getValidationResult());
+
+        stats.setKey(new AxReferenceKey());
+        result = new AxValidationResult();
+        result = stats.validate(result);
+        assertEquals(ValidationResult.INVALID, result.getValidationResult());
+
+        stats.setKey(statsKey);
+        result = new AxValidationResult();
+        result = stats.validate(result);
+        assertEquals(ValidationResult.VALID, result.getValidationResult());
+
+        stats.clean();
+        stats.reset();
+
+        assertCompareTo(stats, statsKey);
+    }
+
+    private void assertSetValuesToStats(AxEngineStats stats) {
         stats.setAverageExecutionTime(123.45);
         assertEquals(Double.valueOf(123.45), Double.valueOf(stats.getAverageExecutionTime()));
 
@@ -105,41 +141,9 @@ public class EngineStatsTest {
         stats.executionEnter(new AxArtifactKey());
         checkEventsCountMetric(stats);
         checkEngineStartTimestampMetric(stats);
+    }
 
-        synchronized (WAIT_LOCK) {
-            try {
-                WAIT_LOCK.wait(10);
-            } catch (InterruptedException e) {
-                fail("test should not throw an exception");
-            }
-        }
-
-        stats.executionExit();
-        checkAvgExecTimeMetric(stats);
-        checkEventsCountMetric(stats);
-        checkLastExecTimeMetric(stats);
-        final double avExecutionTime = stats.getAverageExecutionTime();
-        assertTrue(avExecutionTime >= 2.0 && avExecutionTime < 10.0);
-        stats.engineStop();
-        checkEngineStartTimestampMetric(stats);
-
-        AxValidationResult result = new AxValidationResult();
-        result = stats.validate(result);
-        assertEquals(ValidationResult.VALID, result.getValidationResult());
-
-        stats.setKey(new AxReferenceKey());
-        result = new AxValidationResult();
-        result = stats.validate(result);
-        assertEquals(ValidationResult.INVALID, result.getValidationResult());
-
-        stats.setKey(statsKey);
-        result = new AxValidationResult();
-        result = stats.validate(result);
-        assertEquals(ValidationResult.VALID, result.getValidationResult());
-
-        stats.clean();
-        stats.reset();
-
+    private void assertCompareTo(AxEngineStats stats, AxReferenceKey statsKey) {
         final AxEngineStats clonedStats = new AxEngineStats(stats);
         assertEquals("AxEngineStats:(engineKey=AxReferenceKey:(parentKey", clonedStats.toString().substring(0, 50));
 
@@ -220,10 +224,10 @@ public class EngineStatsTest {
     }
 
     private void checkLastExecTimeMetric(AxEngineStats stats) {
-        Double lastExecTimeMetric = CollectorRegistry.defaultRegistry
+        double lastExecTimeMetric = CollectorRegistry.defaultRegistry
             .getSampleValue("pdpa_engine_last_execution_time_sum", new String[]{AxEngineStats.ENGINE_INSTANCE_ID},
                 new String[]{ENGINE_KEY + ":" + ENGINE_VERSION}) * 1000d;
-        assertEquals(lastExecTimeMetric.longValue(), stats.getLastExecutionTime());
+        assertEquals(lastExecTimeMetric, stats.getLastExecutionTime());
     }
 
     private void checkEngineStartTimestampMetric(AxEngineStats stats) {
diff --git a/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java b/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
index e7fdd2d93..20b3087ef 100644
--- a/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/ApexEngineModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,61 +21,66 @@
 
 package org.onap.policy.apex.model.enginemodel.handling;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 import org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel;
 
-public class ApexEngineModelTest {
+class ApexEngineModelTest {
     private static final String VALID_MODEL_STRING = "***validation of model successful***";
+    private static final String AX_ARTIFACT_KEY = "AxArtifactKey:(name=AnEngine,version=0.0.1)";
+    private static final String ENGINE_MODEL_CLASS = "org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel";
 
-    private static final String INVALID_MODEL_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=AnEngine,version=0.0.1):"
-                    + "org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel:INVALID:"
-                    + "AxEngineModel - state is UNDEFINED\n" + "********************************";
+    private static final String INVALID_MODEL_STRING =
+        "\n" + "***validation of model failed***\n"
+            + AX_ARTIFACT_KEY + ":"
+            + ENGINE_MODEL_CLASS + ":INVALID:"
+            + "AxEngineModel - state is UNDEFINED\n"
+            + "********************************";
 
-    private static final String INVALID_MODEL_MALSTRUCTURED_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=AnEngine,version=0.0.1):"
-                    + "org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel:INVALID:"
-                    + "AxEngineModel - timestamp is not set\n" + "AxArtifactKey:(name=AnEngine,version=0.0.1):"
-                    + "org.onap.policy.apex.model.enginemodel.concepts.AxEngineModel:INVALID:"
-                    + "AxEngineModel - state is UNDEFINED\n" + "********************************";
+    private static final String INVALID_MODEL_MALSTRUCTURED_STRING =
+        "\n" + "***validation of model failed***\n"
+            + AX_ARTIFACT_KEY + ":"
+            + ENGINE_MODEL_CLASS + ":INVALID:"
+            + "AxEngineModel - timestamp is not set\n" + AX_ARTIFACT_KEY + ":"
+            + ENGINE_MODEL_CLASS + ":INVALID:"
+            + "AxEngineModel - state is UNDEFINED\n"
+            + "********************************";
 
     TestApexModel<AxEngineModel> testApexModel;
 
     /**
      * Set up the test.
      *
-     * @throws Exception errors from test setup
      */
-    @Before
-    public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxEngineModel>(AxEngineModel.class, new DummyTestApexEngineModelCreator());
+    @BeforeEach
+    void setup() {
+        testApexModel = new TestApexModel<>(AxEngineModel.class, new DummyTestApexEngineModelCreator());
     }
 
     @Test
-    public void testModelValid() throws Exception {
+    void testModelValid() throws Exception {
         final AxValidationResult result = testApexModel.testApexModelValid();
         assertEquals(VALID_MODEL_STRING, result.toString());
     }
 
     @Test
-    public void testModelVaidateInvalidModel() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateInvalidModel();
+    void testModelValidateInvalidModel() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateInvalidModel();
         assertEquals(INVALID_MODEL_STRING, result.toString());
     }
 
     @Test
-    public void testModelVaidateMalstructured() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateMalstructured();
+    void testModelValidateMalstructured() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateMalstructured();
         assertEquals(INVALID_MODEL_MALSTRUCTURED_STRING, result.toString());
     }
 
     @Test
-    public void testModelWriteReadJson() throws Exception {
+    void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/DummyTestApexEngineModelCreator.java b/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/DummyTestApexEngineModelCreator.java
index 9e7d99b72..99c2144e5 100644
--- a/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/DummyTestApexEngineModelCreator.java
+++ b/model/src/test/java/org/onap/policy/apex/model/enginemodel/handling/DummyTestApexEngineModelCreator.java
@@ -1,19 +1,20 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
@@ -39,16 +40,16 @@ public class DummyTestApexEngineModelCreator implements TestApexModelCreator<AxE
     @Override
     public AxEngineModel getModel() {
         final AxContextSchema schema0 = new AxContextSchema(new AxArtifactKey("StringType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
         final AxContextSchema schema1 = new AxContextSchema(new AxArtifactKey("MapType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
 
         final AxContextSchemas schemas = new AxContextSchemas(new AxArtifactKey("ContextSchemas", "0.0.1"));
         schemas.getSchemasMap().put(schema0.getKey(), schema0);
         schemas.getSchemasMap().put(schema1.getKey(), schema1);
 
         final AxContextAlbum album0 =
-                new AxContextAlbum(new AxArtifactKey("contextAlbum0", "0.0.1"), "APPLICATION", true, schema1.getKey());
+            new AxContextAlbum(new AxArtifactKey("contextAlbum0", "0.0.1"), "APPLICATION", true, schema1.getKey());
 
         final AxContextAlbums albums = new AxContextAlbums(new AxArtifactKey("context", "0.0.1"));
         albums.getAlbumsMap().put(album0.getKey(), album0);
@@ -59,7 +60,7 @@ public class DummyTestApexEngineModelCreator implements TestApexModelCreator<AxE
         engineModel.setTimestamp(System.currentTimeMillis());
         engineModel.setState(AxEngineState.EXECUTING);
         engineModel.setStats(new AxEngineStats(new AxReferenceKey(engineModel.getKey(), "EngineStats"),
-                System.currentTimeMillis(), 100, 205, 200, 12345, 9876));
+            System.currentTimeMillis(), 100, 205, 200, 12345, 9876));
         engineModel.getKeyInformation().generateKeyInfo(engineModel);
 
         final AxValidationResult result = new AxValidationResult();
@@ -75,7 +76,7 @@ public class DummyTestApexEngineModelCreator implements TestApexModelCreator<AxE
         engineModel.setTimestamp(System.currentTimeMillis());
         engineModel.setState(AxEngineState.UNDEFINED);
         engineModel.setStats(new AxEngineStats(new AxReferenceKey(engineModel.getKey(), "EngineStats"),
-                System.currentTimeMillis(), 100, 205, 200, 12345, 9876));
+            System.currentTimeMillis(), 100, 205, 200, 12345, 9876));
         engineModel.getKeyInformation().generateKeyInfo(engineModel);
 
         return engineModel;
@@ -98,14 +99,14 @@ public class DummyTestApexEngineModelCreator implements TestApexModelCreator<AxE
         final AxEngineModel engineModel = getModel();
 
         final AxContextSchema schema0 = new AxContextSchema(new AxArtifactKey("StringType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
         final AxContextSchema schema1 = new AxContextSchema(new AxArtifactKey("MapType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
 
         engineModel.getKeyInformation().getKeyInfoMap().put(schema0.getKey(),
-                new AxKeyInfo(schema0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000001"), ""));
+            new AxKeyInfo(schema0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000001"), ""));
         engineModel.getKeyInformation().getKeyInfoMap().put(schema1.getKey(),
-                new AxKeyInfo(schema1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000002"), ""));
+            new AxKeyInfo(schema1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000002"), ""));
 
         return engineModel;
     }
@@ -115,14 +116,14 @@ public class DummyTestApexEngineModelCreator implements TestApexModelCreator<AxE
         final AxEngineModel engineModel = getModel();
 
         final AxContextSchema schema0 = new AxContextSchema(new AxArtifactKey("StringType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem000");
         final AxContextSchema schema1 = new AxContextSchema(new AxArtifactKey("MapType", "0.0.1"), "Java",
-                "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
+            "org.onap.policy.apex.model.enginemodel.concepts.TestContextItem00A");
 
         engineModel.getKeyInformation().getKeyInfoMap().put(schema0.getKey(),
-                new AxKeyInfo(schema0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000000"), ""));
+            new AxKeyInfo(schema0.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000000"), ""));
         engineModel.getKeyInformation().getKeyInfoMap().put(schema1.getKey(),
-                new AxKeyInfo(schema1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000001"), ""));
+            new AxKeyInfo(schema1.getKey(), UUID.fromString("00000000-0000-0000-0000-000000000001"), ""));
 
         return engineModel;
     }
diff --git a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventModelTest.java b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventModelTest.java
index cdc5fecf6..4113247fd 100644
--- a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,34 +21,30 @@
 
 package org.onap.policy.apex.model.eventmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
 import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
 
 /**
  * Test event models.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class EventModelTest {
+class EventModelTest {
 
     @Test
-    public void testEventModel() {
-        assertNotNull(new AxEventModel());
-        assertNotNull(new AxEventModel(new AxArtifactKey()));
-        assertNotNull(
-                new AxEventModel(new AxArtifactKey(), new AxContextSchemas(), new AxKeyInformation(), new AxEvents()));
-
+    void testEventModel() {
         final AxArtifactKey modelKey = new AxArtifactKey("ModelKey", "0.0.1");
         final AxArtifactKey schemasKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxArtifactKey eventsKey = new AxArtifactKey("EventsKey", "0.0.1");
         final AxArtifactKey keyInfoKey = new AxArtifactKey("SchemasKey", "0.0.1");
         final AxEventModel model = new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey));
+            new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey));
         model.register();
 
         model.clean();
@@ -64,24 +60,24 @@ public class EventModelTest {
         assertNotEquals(model, (Object) "Hello");
         assertNotEquals(model, new AxEventModel(new AxArtifactKey()));
         assertNotEquals(model, new AxEventModel(modelKey, new AxContextSchemas(), new AxKeyInformation(keyInfoKey),
-                new AxEvents(eventsKey)));
+            new AxEvents(eventsKey)));
         assertNotEquals(model, new AxEventModel(modelKey, new AxContextSchemas(schemasKey), new AxKeyInformation(),
-                new AxEvents(eventsKey)));
+            new AxEvents(eventsKey)));
         assertNotEquals(model, new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxEvents()));
+            new AxKeyInformation(keyInfoKey), new AxEvents()));
         assertEquals(model, new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey)));
+            new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey)));
 
         assertEquals(0, model.compareTo(model));
         assertEquals(0, model.compareTo(clonedModel));
         assertNotEquals(0, model.compareTo(new AxArtifactKey()));
         assertNotEquals(0, model.compareTo(new AxEventModel(modelKey, new AxContextSchemas(),
-                new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey))));
+            new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey))));
         assertNotEquals(0, model.compareTo(new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(), new AxEvents(eventsKey))));
+            new AxKeyInformation(), new AxEvents(eventsKey))));
         assertNotEquals(0, model.compareTo(new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxEvents())));
+            new AxKeyInformation(keyInfoKey), new AxEvents())));
         assertEquals(0, model.compareTo(new AxEventModel(modelKey, new AxContextSchemas(schemasKey),
-                new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey))));
+            new AxKeyInformation(keyInfoKey), new AxEvents(eventsKey))));
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventsTest.java b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventsTest.java
index 7062fcb3c..760a8375c 100644
--- a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/EventsTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2022, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2022 Bell Canada.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,14 +22,14 @@
 
 package org.onap.policy.apex.model.eventmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.TreeMap;
 import java.util.TreeSet;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
@@ -42,20 +42,13 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class EventsTest {
+class EventsTest {
 
     @Test
-    public void testEvents() {
+    void testEvents() {
         final TreeMap<String, AxField> parameterMap = new TreeMap<>();
         final TreeMap<String, AxField> parameterMapEmpty = new TreeMap<>();
 
-        assertNotNull(new AxEvent());
-        assertNotNull(new AxEvent(new AxArtifactKey()));
-        assertNotNull(new AxEvent(new AxArtifactKey(), "namespace"));
-        assertNotNull(new AxEvent(new AxArtifactKey(), "namespace", "source", "target"));
-        assertNotNull(new AxEvent(new AxArtifactKey(), "namespace", "source", "target"));
-        assertNotNull(new AxEvent(new AxArtifactKey(), "namespace", "source", "target", parameterMap, ""));
-
         final AxEvent event = new AxEvent();
 
         final AxArtifactKey eventKey = new AxArtifactKey("EventName", "0.0.1");
@@ -97,12 +90,36 @@ public class EventsTest {
         assertEquals("EventName:0.0.1", event.getKey().getId());
         assertEquals("EventName:0.0.1", event.getKeys().get(0).getId());
 
-        assertTrue("Field0", event.getFields().contains(eventField));
-        assertTrue(event.hasFields(new TreeSet<AxField>(parameterMap.values())));
+        assertTrue(event.getFields().contains(eventField));
+        assertTrue(event.hasFields(new TreeSet<>(parameterMap.values())));
+
+        assertValidationResults_SingleEvent(event, eventKey, eventField, eventFieldBadParent);
+
+        event.clean();
+        event.buildReferences();
+        assertNotEquals(AxKey.NULL_KEY_NAME,
+            event.getParameterMap().values().iterator().next().getKey().getParentKeyName());
+
+        assertCompareTo(event, parameterMap, eventKey, parameterMapEmpty);
+
+        assertNotNull(event.getKeys());
+
+        final AxEvents events = new AxEvents();
+        assertValidationResult_GroupEvents(events, eventKey, event);
+
+        events.clean();
+        event.buildReferences();
+        assertNotEquals(AxKey.NULL_KEY_NAME,
+            event.getParameterMap().values().iterator().next().getKey().getParentKeyName());
+
+        assertCompareToSpecificEvents(events, event, eventKey);
+    }
 
+    private static void assertValidationResults_SingleEvent(AxEvent event, AxArtifactKey eventKey, AxField eventField,
+                                  AxField eventFieldBadParent) {
         AxValidationResult result = new AxValidationResult();
         result = event.validate(result);
-        assertEquals(AxValidationResult.ValidationResult.VALID, result.getValidationResult());
+        assertEquals(ValidationResult.VALID, result.getValidationResult());
 
         event.setKey(AxArtifactKey.getNullKey());
         result = new AxValidationResult();
@@ -189,12 +206,10 @@ public class EventsTest {
         result = event.validate(result);
         assertEquals(ValidationResult.INVALID, result.getValidationResult());
         event.setToscaPolicyState(AxToscaPolicyProcessingStatus.ENTRY.name());
+    }
 
-        event.clean();
-        event.buildReferences();
-        assertNotEquals(AxKey.NULL_KEY_NAME,
-            event.getParameterMap().values().iterator().next().getKey().getParentKeyName());
-
+    private static void assertCompareTo(AxEvent event, TreeMap<String, AxField> parameterMap,
+                                        AxArtifactKey eventKey, TreeMap<String, AxField> parameterMapEmpty) {
         final AxEvent clonedEvent = new AxEvent(event);
         assertEquals("AxEvent:(key=AxArtifactKey:(name=EventName,version=0.0.1),nameSpace=namespace",
             clonedEvent.toString().substring(0, 77));
@@ -237,10 +252,10 @@ public class EventsTest {
             AxToscaPolicyProcessingStatus.ENTRY.name())));
         assertEquals(0, event.compareTo(new AxEvent(eventKey, "namespace", "source", "target", parameterMap,
             AxToscaPolicyProcessingStatus.ENTRY.name())));
+    }
 
-        assertNotNull(event.getKeys());
-
-        final AxEvents events = new AxEvents();
+    private static void assertValidationResult_GroupEvents(AxEvents events, AxArtifactKey eventKey, AxEvent event) {
+        AxValidationResult result;
         result = new AxValidationResult();
         result = events.validate(result);
         assertEquals(ValidationResult.INVALID, result.getValidationResult());
@@ -287,18 +302,16 @@ public class EventsTest {
         result = new AxValidationResult();
         result = events.validate(result);
         assertEquals(ValidationResult.VALID, result.getValidationResult());
+    }
 
-        events.clean();
-        event.buildReferences();
-        assertNotEquals(AxKey.NULL_KEY_NAME,
-            event.getParameterMap().values().iterator().next().getKey().getParentKeyName());
-
+    private static void assertCompareToSpecificEvents(AxEvents events, AxEvent event, AxArtifactKey eventKey) {
         final AxEvents clonedEvents = new AxEvents(events);
         assertEquals("AxEvents:(key=AxArtifactKey:(name=EventsKey,version=0.0.1),e",
             clonedEvents.toString().substring(0, 60));
 
         assertNotEquals(0, events.hashCode());
 
+        Object helloObj = "Hello";
         assertEquals(events, clonedEvents);
         assertNotNull(events);
         assertNotEquals(event, helloObj);
@@ -318,6 +331,6 @@ public class EventsTest {
         assertEquals("EventName", events.get("EventName").getKey().getName());
         assertEquals("EventName", events.get("EventName", "0.0.1").getKey().getName());
         assertEquals(1, events.getAll("EventName", "0.0.1").size());
-        assertEquals(0, events.getAll("NonExistantEventsName").size());
+        assertEquals(0, events.getAll("NonExistentEventsName").size());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/FieldTest.java b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/FieldTest.java
index 6ec46dbd5..85b3a48e3 100644
--- a/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/FieldTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/eventmodel/concepts/FieldTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,11 +21,13 @@
 
 package org.onap.policy.apex.model.eventmodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -36,32 +38,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class FieldTest {
+class FieldTest {
 
     @Test
-    public void testField() {
-        assertNotNull(new AxField());
-        assertNotNull(new AxField(new AxReferenceKey()));
-        assertNotNull(new AxField(new AxReferenceKey(), new AxArtifactKey()));
-        assertNotNull(new AxField(new AxReferenceKey(), new AxArtifactKey(), false));
-        assertNotNull(new AxField("LocalName", new AxArtifactKey(), false));
-        assertNotNull(new AxField("LocalName", new AxArtifactKey()));
-        assertNotNull(new AxField("LocalName", new AxArtifactKey(), false));
-
-        assertNotNull(new AxInputField());
-        assertNotNull(new AxInputField(new AxReferenceKey()));
-        assertNotNull(new AxInputField(new AxReferenceKey(), new AxArtifactKey()));
-        assertNotNull(new AxInputField(new AxReferenceKey(), new AxArtifactKey(), true));
-        assertNotNull(new AxInputField("LocalName", new AxArtifactKey()));
-        assertNotNull(new AxInputField(new AxInputField()));
-
-        assertNotNull(new AxOutputField());
-        assertNotNull(new AxOutputField(new AxReferenceKey()));
-        assertNotNull(new AxOutputField(new AxReferenceKey(), new AxArtifactKey()));
-        assertNotNull(new AxOutputField(new AxReferenceKey(), new AxArtifactKey(), false));
-        assertNotNull(new AxOutputField("LocalName", new AxArtifactKey()));
-        assertNotNull(new AxOutputField(new AxOutputField()));
-
+    void testField() {
         final AxField field = new AxField();
 
         final AxReferenceKey fieldKey = new AxReferenceKey("FieldName", "0.0.1", "PLN", "LN");
@@ -73,13 +53,21 @@ public class FieldTest {
         field.setSchema(schemaKey);
         assertEquals("SchemaName:0.0.1", field.getSchema().getId());
 
-        assertEquals(false, field.getOptional());
+        assertFalse(field.getOptional());
         field.setOptional(true);
-        assertEquals(true, field.getOptional());
+        assertTrue(field.getOptional());
+
+        assertValidationResult(field, fieldKey, schemaKey);
+
+        field.clean();
+
+        assertCompareTo(field, fieldKey, schemaKey);
+    }
 
+    private static void assertValidationResult(AxField field, AxReferenceKey fieldKey, AxArtifactKey schemaKey) {
         AxValidationResult result = new AxValidationResult();
         result = field.validate(result);
-        assertEquals(AxValidationResult.ValidationResult.VALID, result.getValidationResult());
+        assertEquals(ValidationResult.VALID, result.getValidationResult());
 
         field.setKey(AxReferenceKey.getNullKey());
         result = new AxValidationResult();
@@ -100,13 +88,13 @@ public class FieldTest {
         result = new AxValidationResult();
         result = field.validate(result);
         assertEquals(ValidationResult.VALID, result.getValidationResult());
+    }
 
-        field.clean();
-
+    private static void assertCompareTo(AxField field, AxReferenceKey fieldKey, AxArtifactKey schemaKey) {
         final AxField clonedField = new AxField(field);
         assertEquals("AxField:(key=AxReferenceKey:(parentKeyName=FieldName,parentKeyVersion=0.0.1,"
-                        + "parentLocalName=PLN,localName=LN),fieldSchemaKey="
-                        + "AxArtifactKey:(name=SchemaName,version=0.0.1),optional=true)", clonedField.toString());
+            + "parentLocalName=PLN,localName=LN),fieldSchemaKey="
+            + "AxArtifactKey:(name=SchemaName,version=0.0.1),optional=true)", clonedField.toString());
 
         assertNotEquals(0, field.hashCode());
         // disabling sonar because this code tests the equals() method
@@ -124,7 +112,7 @@ public class FieldTest {
         assertNotEquals(0, field.compareTo(new AxArtifactKey()));
         assertNotEquals(0, field.compareTo(null));
         assertNotEquals(0,
-                        field.compareTo(new AxField(AxReferenceKey.getNullKey(), AxArtifactKey.getNullKey(), false)));
+            field.compareTo(new AxField(AxReferenceKey.getNullKey(), AxArtifactKey.getNullKey(), false)));
         assertNotEquals(0, field.compareTo(new AxField(fieldKey, AxArtifactKey.getNullKey(), false)));
         assertNotEquals(0, field.compareTo(new AxField(fieldKey, schemaKey, false)));
         assertEquals(0, field.compareTo(new AxField(fieldKey, schemaKey, true)));
diff --git a/model/src/test/java/org/onap/policy/apex/model/eventmodel/handling/ApexEventModelTest.java b/model/src/test/java/org/onap/policy/apex/model/eventmodel/handling/ApexEventModelTest.java
index 21b97c454..df1857c82 100644
--- a/model/src/test/java/org/onap/policy/apex/model/eventmodel/handling/ApexEventModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/eventmodel/handling/ApexEventModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,259 +21,76 @@
 
 package org.onap.policy.apex.model.eventmodel.handling;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
 
-import org.junit.Before;
-import org.junit.Test;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 import org.onap.policy.apex.model.eventmodel.concepts.AxEventModel;
+import org.onap.policy.common.utils.resources.ResourceUtils;
 
-public class ApexEventModelTest {
+class ApexEventModelTest {
     private static final String VALID_MODEL_STRING = "***validation of model successful***";
 
-    private static final String OBSERVATION_MODEL_STRING = "\n"
-                    + "***observations noted during validation of model***\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event2,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event2,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "********************************";
-
-    private static final String WARNING_MODEL_STRING = "\n" + "***warnings issued during validation of model***\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event2,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank\n"
-                    + "AxArtifactKey:(name=event2,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event2,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "********************************";
-
-    private static final String INVALID_MODEL_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):"
-                    + "org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:"
-                    + "keyInfoMap may not be empty\n" + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=smallEventModel,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=Schemas,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=BigIntType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=BooleanType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=IntType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=MapType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=SetType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=StringType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=smallEventMap,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=event0,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par0)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par2)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par3)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par4)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par5)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par6)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=event1,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "duplicate key AxArtifactKey:(name=event1,version=0.0.1) found\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=event1,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "duplicate key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,"
-                    + "localName=theOnlyPar) found\n" + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:INVALID:"
-                    + "parent key on parameter field AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,"
-                    + "parentLocalName=NULL,localName=theOnlyPar) does not equal event key\n"
-                    + "AxArtifactKey:(name=smallEventMap,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:"
-                    + "key on event entry key AxArtifactKey:(name=event2,version=0.0.1) does not equal event value key "
-                    + "AxArtifactKey:(name=event1,version=0.0.1)\n" + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:INVALID:"
-                    + "parent key on parameter field AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,"
-                    + "parentLocalName=NULL,localName=theOnlyPar) does not equal event key\n"
-                    + "********************************";
-
-    private static final String INVALID_MODEL_MALSTRUCTURED_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):"
-                    + "org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:"
-                    + "keyInfoMap may not be empty\n" + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=smallEventModel,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=Schemas,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=SetType,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=smallEventMap,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=event1,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event1,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "duplicate key AxArtifactKey:(name=event1,version=0.0.1) found\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=event1,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "duplicate key AxReferenceKey:(parentKeyName=event1,parentKeyVersion=0.0.1,"
-                    + "parentLocalName=NULL,localName=theOnlyPar) found\n"
-                    + "AxArtifactKey:(name=smallEventModel,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:"
-                    + "key information not found for parent key of key AxReferenceKey:"
-                    + "(parentKeyName=event1,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "AxArtifactKey:(name=smallEventMap,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:"
-                    + "key on event entry key AxArtifactKey:(name=event2,version=0.0.1) does not equal event value key "
-                    + "AxArtifactKey:(name=event1,version=0.0.1)\n" + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank\n"
-                    + "AxArtifactKey:(name=event1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank\n"
-                    + "********************************";
+    private static final String OBSERVATION_MODEL_STRING =
+        "eventmodel/handling/ApexEventModelTest_ObservationModel.txt";
+    private static final String WARNING_MODEL_STRING = "eventmodel/handling/ApexEventModelTest_WarningModel.txt";
+    private static final String INVALID_MODEL_STRING = "eventmodel/handling/ApexEventModelTest_InvalidModel.txt";
+    private static final String INVALID_MODEL_MALSTRUCTURED_STRING =
+        "eventmodel/handling/ApexEventModelTest_InvalidModelMalStructured.txt";
 
     TestApexModel<AxEventModel> testApexModel;
 
     /**
      * Set up the test.
      *
-     * @throws Exception exceptions from the test
      */
-    @Before
-    public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxEventModel>(AxEventModel.class, new DummyTestApexEventModelCreator());
+    @BeforeEach
+    void setup() {
+        testApexModel = new TestApexModel<>(AxEventModel.class, new DummyTestApexEventModelCreator());
     }
 
     @Test
-    public void testModelValid() throws Exception {
+    void testModelValid() throws Exception {
         final AxValidationResult result = testApexModel.testApexModelValid();
         assertEquals(VALID_MODEL_STRING, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateObservation() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateObservation();
-        assertEquals(OBSERVATION_MODEL_STRING, result.toString());
+    void testApexModelValidateObservation() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateObservation();
+        String expected = ResourceUtils.getResourceAsString(OBSERVATION_MODEL_STRING);
+        assertEquals(expected, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateWarning() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateWarning();
-        assertEquals(WARNING_MODEL_STRING, result.toString());
+    void testApexModelValidateWarning() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateWarning();
+        String expected = ResourceUtils.getResourceAsString(WARNING_MODEL_STRING);
+        assertEquals(expected, result.toString());
     }
 
     @Test
-    public void testModelVaidateInvalidModel() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateInvalidModel();
-        assertEquals(INVALID_MODEL_STRING, result.toString());
+    void testModelValidateInvalidModel() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateInvalidModel();
+        String expected = ResourceUtils.getResourceAsString(INVALID_MODEL_STRING);
+        assertEquals(expected, result.toString());
     }
 
     @Test
-    public void testModelVaidateMalstructured() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateMalstructured();
-        assertEquals(INVALID_MODEL_MALSTRUCTURED_STRING, result.toString());
+    void testModelValidateMalstructured() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateMalstructured();
+        String expected = ResourceUtils.getResourceAsString(INVALID_MODEL_MALSTRUCTURED_STRING);
+        assertEquals(expected, result.toString());
     }
 
     @Test
-    public void testModelWriteReadJson() throws Exception {
+    void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexApiResultTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexApiResultTest.java
index 3c2af18ea..9d009d2b9 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexApiResultTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexApiResultTest.java
@@ -1,55 +1,46 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.IOException;
 import java.util.Arrays;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.modelapi.ApexApiResult.Result;
 
 /**
  * Test API results.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexApiResultTest {
+class ApexApiResultTest {
 
     @Test
-    public void testApiResult() {
-        assertNotNull(new ApexApiResult());
-
-        for (final Result result : Result.values()) {
-            assertNotNull(new ApexApiResult(result));
-        }
-
-        assertNotNull(new ApexApiResult(Result.SUCCESS, "Result Message"));
-        assertNotNull(new ApexApiResult(Result.FAILED, new IOException("IO Exception message")));
-        assertNotNull(new ApexApiResult(Result.FAILED, "Result Message", new IOException("IO Exception message")));
-
+    void testApiResult() {
         final ApexApiResult result =
-                new ApexApiResult(Result.FAILED, "Result Message", new IOException("IO Exception message"));
+            new ApexApiResult(Result.FAILED, "Result Message", new IOException("IO Exception message"));
 
         assertFalse(result.isOk());
         assertTrue(result.isNok());
@@ -74,7 +65,14 @@ public class ApexApiResultTest {
         assertEquals("Third Message", result2.getMessages().get(2));
 
         assertEquals("result: OTHER_ERROR\nFirst Message\nSecond Message\nThird Message\n", result2.toString());
-        assertEquals("{\n" + "\"result\": \"OTHER_ERROR\",\n" + "\"messages\": [\n" + "\"First Message\",\n"
-                + "\"Second Message\",\n" + "\"Third Message\"]\n" + "}\n", result2.toJson());
+        assertEquals("""
+            {
+            "result": "OTHER_ERROR",
+            "messages": [
+            "First Message",
+            "Second Message",
+            "Third Message"]
+            }
+            """, result2.toJson());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextAlbumTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextAlbumTest.java
index 5ce6b6760..6d9c7e404 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextAlbumTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextAlbumTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,18 +21,19 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Context album for API tests.
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiContextAlbumTest {
+class ApexEditorApiContextAlbumTest {
+
     @Test
-    public void testContextAlbumCrud() {
+    void testContextAlbumCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validateContextAlbum(null, null);
@@ -44,51 +45,74 @@ public class ApexEditorApiContextAlbumTest {
         result = apexModel.loadFromFile("src/test/resources/models/PolicyModel.json");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.createContextAlbum("MyMap002", "0.0.2", "APPLICATION", "true", "MapType", "0.0.1",
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", "0.1.2", "ZOOBY", "false", "MapType", "0.0.1",
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 012");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", "0.1.4", "UNDEFINED", null, "MapType", "0.0.1",
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 014");
+        assertCreateContextAlbum(apexModel);
+
+        result = apexModel.validateContextAlbum(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, null, null, null, null, null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", null, null, null, null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", null, null, null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "", null, null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "+++", null, null, null);
+
+        assertUpdateContextAlbum(apexModel);
+
+        assertListContextAlbum(apexModel);
+
+        assertDeleteContextAlbum(apexModel);
+    }
+
+    private static void assertDeleteContextAlbum(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.deleteContextAlbum("@£%%$", null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapZooby", null, null, null);
+
+        result = apexModel.deleteContextAlbum("MyMap012", "0.1.1");
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "--++", null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "0.0.2", null, null);
+
+        result = apexModel.deleteContextAlbum("MyMap012oooo", null);
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "0.0.1", null, null);
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", null, null, null);
-        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap002", "0.0.2", "APPLICATION", "true", "MapType", null,
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
-        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap011", "0.1.2", "APPLICATION", "true", "MapType", "0.0.1",
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
+
+        result = apexModel.listContextAlbum("MyMap012", null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(3, result.getMessages().size());
 
         result = apexModel.deleteContextAlbum("MyMap012", "0.1.2");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextAlbum("MyMap012", "0.1.2", "ZOOBY", "false", "MapType", "0.0.1",
-            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 012");
+
+        result = apexModel.listContextAlbum("MyMap012", null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(2, result.getMessages().size());
 
-        result = apexModel.validateContextAlbum(null, null);
+        result = apexModel.deleteContextAlbum("MyMap012", null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(2, result.getMessages().size());
+
+        result = apexModel.listContextAlbum("MyMap012", null);
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+
+        result = apexModel.deleteContextAlbum(null, null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(4, result.getMessages().size());
+
+        result = apexModel.listContextAlbum(null, null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(0, result.getMessages().size());
+    }
+
+    private static void assertListContextAlbum(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.listContextAlbum("@£%%$", null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.listContextAlbum(null, null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.listContextAlbum("MyMap012", null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.listContextAlbum("MyMap012", "0.0.2");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.listContextAlbum("MyMap012", "0.2.5");
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+        result = apexModel.listContextAlbum("MyMap014", null);
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+    }
 
+    private static void assertUpdateContextAlbum(ApexModel apexModel) {
+        ApexApiResult result;
         result = apexModel.updateContextAlbum(null, null, null, null, null, null, null, null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
         result = apexModel.updateContextAlbum("MyMap002", "0.0.2", null, null, null, null, null, null);
@@ -123,54 +147,50 @@ public class ApexEditorApiContextAlbumTest {
         result = apexModel.updateContextAlbum("MyMap012", null, "APPLICATION", "Hello", "StringType", "0.0.1", null,
             null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+    }
 
-        result = apexModel.listContextAlbum("@£%%$", null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-
-        result = apexModel.listContextAlbum(null, null);
+    private static void assertCreateContextAlbum(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.createContextAlbum("MyMap002", "0.0.2", "APPLICATION", "true", "MapType", "0.0.1",
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.listContextAlbum("MyMap012", null);
+        result = apexModel.createContextAlbum("MyMap012", "0.1.2", "ZOOBY", "false", "MapType", "0.0.1",
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 012");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.listContextAlbum("MyMap012", "0.0.2");
+        result = apexModel.createContextAlbum("MyMap012", "0.1.4", "UNDEFINED", null, "MapType", "0.0.1",
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 014");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.listContextAlbum("MyMap012", "0.2.5");
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-        result = apexModel.listContextAlbum("MyMap014", null);
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-
-        result = apexModel.deleteContextAlbum("@£%%$", null);
+        result = apexModel.createContextAlbum("MyMap012", null, null, null, null, null, null, null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-
-        result = apexModel.deleteContextAlbum("MyMap012", "0.1.1");
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", null, null, null, null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", null, null, null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "", null, null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "+++", null, null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapZooby", null, null, null);
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-
-        result = apexModel.deleteContextAlbum("MyMap012oooo", null);
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "--++", null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "0.0.2", null, null);
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-
-        result = apexModel.listContextAlbum("MyMap012", null);
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(3, result.getMessages().size());
-
-        result = apexModel.deleteContextAlbum("MyMap012", "0.1.2");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-
-        result = apexModel.listContextAlbum("MyMap012", null);
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", "0.0.1", null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(2, result.getMessages().size());
-
-        result = apexModel.deleteContextAlbum("MyMap012", null);
+        result = apexModel.createContextAlbum("MyMap012", null, "EPHEMERAL", "false", "MapType", null, null, null);
+        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
+        result = apexModel.createContextAlbum("MyMap002", "0.0.2", "APPLICATION", "true", "MapType", null,
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
+        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
+        result = apexModel.createContextAlbum("MyMap011", "0.1.2", "APPLICATION", "true", "MapType", "0.0.1",
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 002");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(2, result.getMessages().size());
-
-        result = apexModel.listContextAlbum("MyMap012", null);
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
 
-        result = apexModel.deleteContextAlbum(null, null);
+        result = apexModel.deleteContextAlbum("MyMap012", "0.1.2");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(4, result.getMessages().size());
-
-        result = apexModel.listContextAlbum(null, null);
+        result = apexModel.createContextAlbum("MyMap012", "0.1.2", "ZOOBY", "false", "MapType", "0.0.1",
+            "1fa2e430-f2b2-11e6-bc64-92361f002700", "A description of 012");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(0, result.getMessages().size());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextSchemaTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextSchemaTest.java
index 20310a29e..e7a6b112f 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextSchemaTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiContextSchemaTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,17 +21,19 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Context schema for API tests.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiContextSchemaTest {
+class ApexEditorApiContextSchemaTest {
+
     @Test
-    public void testContextSchemaCrud() {
+    void testContextSchemaCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validateContextSchemas(null, null);
@@ -45,59 +47,60 @@ public class ApexEditorApiContextSchemaTest {
         result = apexModel.listContextSchemas(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.createContextSchema("Hello", "0.0.2", "Java", "java.lang.String",
-                "1fa2e430-f2b2-11e6-bc64-92361f002671", "A description of hello");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", "0.1.2", "Java", "java.lang.String",
-                "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of hola");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
-                "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", null, "Java", "java.lang.String", null, null);
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", null, "Java", "java.lang.String", null, null);
-        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
-        result = apexModel.deleteContextSchema("Hello", "0.1.4");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
-                "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
+        assertCreateContextSchema(apexModel);
+
+        result = apexModel.validateContextSchemas(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.createContextSchema("Hello2", null, null, "java.lang.String", null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextSchema("Hello2", null, null, null, null, null);
+        assertUpdateContextSchema(apexModel);
+
+        assertListContextSchemas(apexModel);
+
+        assertDeleteContextSchema(apexModel);
+    }
+
+    private static void assertDeleteContextSchema(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.deleteContextSchema("@£%%$", null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.createContextSchema("Hello2", null, "Java", "java.lang.String", null, null);
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.createContextSchema("Hello", "0.1.2", "Java", "java.lang.Float",
-                "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of hola");
-        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
+        result = apexModel.deleteContextSchema("Hello", "0.1.1");
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
 
-        result = apexModel.deleteContextSchema("Hello", "0.1.4");
-        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
-                "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
+        result = apexModel.deleteContextSchema("Hellooooo", null);
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+
+        result = apexModel.listContextSchemas("Hello", null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(4, result.getMessages().size());
 
-        result = apexModel.validateContextSchemas(null, null);
+        result = apexModel.deleteContextSchema("Hello", "0.1.2");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.updateContextSchema(null, null, null, null, null, null);
-        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.listContextSchemas("Hello", null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(3, result.getMessages().size());
 
-        result = apexModel.updateContextSchema("Hello", "0.0.2", null, null, null, "An updated description of hello");
+        result = apexModel.deleteContextSchema("Hello", null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.updateContextSchema("Hello", "0.0.2", null, null, null, null);
+
+        result = apexModel.listContextSchemas("Hello", null);
+        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+
+        result = apexModel.listContextSchemas(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        result = apexModel.updateContextSchema("Hello", "0.1.2", "Java", "java.lang.Integer",
-                "1fa2e430-f2b2-11e6-bc64-92361f002673", "A further updated description of hola");
+
+        result = apexModel.deleteContextSchema(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(5, result.getMessages().size());
 
-        result = apexModel.updateContextSchema("Hello2", "0.0.2", null, null, null, "An updated description of hello");
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+        result = apexModel.listContextSchemas(null, null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        assertEquals(0, result.getMessages().size());
+    }
 
+    private static void assertListContextSchemas(ApexModel apexModel) {
+        ApexApiResult result;
         result = apexModel.listContextSchemas("@£%%$", null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
 
@@ -112,42 +115,61 @@ public class ApexEditorApiContextSchemaTest {
         result = apexModel.listContextSchemas(null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
         assertEquals(9, result.getMessages().size());
+    }
 
-        result = apexModel.deleteContextSchema("@£%%$", null);
+    private static void assertUpdateContextSchema(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.updateContextSchema(null, null, null, null, null, null);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
 
-        result = apexModel.deleteContextSchema("Hello", "0.1.1");
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+        result = apexModel.updateContextSchema("Hello", "0.0.2", null, null, null, "An updated description of hello");
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.updateContextSchema("Hello", "0.0.2", null, null, null, null);
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.updateContextSchema("Hello", "0.1.2", "Java", "java.lang.Integer",
+            "1fa2e430-f2b2-11e6-bc64-92361f002673", "A further updated description of hola");
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.deleteContextSchema("Hellooooo", null);
+        result = apexModel.updateContextSchema("Hello2", "0.0.2", null, null, null, "An updated description of hello");
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
+    }
 
-        result = apexModel.listContextSchemas("Hello", null);
+    private static void assertCreateContextSchema(ApexModel apexModel) {
+        ApexApiResult result;
+        result = apexModel.createContextSchema("Hello", "0.0.2", "Java", "java.lang.String",
+            "1fa2e430-f2b2-11e6-bc64-92361f002671", "A description of hello");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(4, result.getMessages().size());
-
-        result = apexModel.deleteContextSchema("Hello", "0.1.2");
+        result = apexModel.createContextSchema("Hello", "0.1.2", "Java", "java.lang.String",
+            "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of hola");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-
-        result = apexModel.listContextSchemas("Hello", null);
+        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
+            "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(3, result.getMessages().size());
-
-        result = apexModel.deleteContextSchema("Hello", null);
+        result = apexModel.createContextSchema("Hello", null, "Java", "java.lang.String", null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-
-        result = apexModel.listContextSchemas("Hello", null);
-        assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
-
-        result = apexModel.listContextSchemas(null, null);
+        result = apexModel.createContextSchema("Hello", null, "Java", "java.lang.String", null, null);
+        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
+        result = apexModel.deleteContextSchema("Hello", "0.1.4");
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
+            "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
 
-        result = apexModel.deleteContextSchema(null, null);
+        result = apexModel.createContextSchema("Hello2", null, null, "java.lang.String", null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextSchema("Hello2", null, null, null, null, null);
+        assertEquals(ApexApiResult.Result.FAILED, result.getResult());
+        result = apexModel.createContextSchema("Hello2", null, "Java", "java.lang.String", null, null);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(5, result.getMessages().size());
 
-        result = apexModel.listContextSchemas(null, null);
+        result = apexModel.createContextSchema("Hello", "0.1.2", "Java", "java.lang.Float",
+            "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of hola");
+        assertEquals(ApexApiResult.Result.CONCEPT_EXISTS, result.getResult());
+
+        result = apexModel.deleteContextSchema("Hello", "0.1.4");
+        assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
+        result = apexModel.createContextSchema("Hello", "0.1.4", "Java", "java.lang.String",
+            "1fa2e430-f2b2-11e6-bc64-92361f002672", "A description of connichi wa");
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
-        assertEquals(0, result.getMessages().size());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiEventTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiEventTest.java
index ac9265e84..c94882b16 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiEventTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiEventTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2022 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,18 +22,19 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test events for API tests.
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiEventTest {
+class ApexEditorApiEventTest {
+
     @Test
-    public void testEventCrud() {
+    void testEventCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validateEvent(null, null);
@@ -141,7 +142,7 @@ public class ApexEditorApiEventTest {
         result = apexModel.createEventPar("MyEvent002", "0.0.2", "NewPar00", null, null, true);
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
 
-        result = apexModel.createContextSchema("eventContextItem0", "0.0.1", "Java", "java.lang.Integer",
+        apexModel.createContextSchema("eventContextItem0", "0.0.1", "Java", "java.lang.Integer",
             "1fa2e430-f2b2-11e6-bc64-92361f002673", "A further updated description of hola");
         result = apexModel.createEventPar("MyEvent002", "0.0.2", "NewPar00", "eventContextItem0", null, false);
         assertEquals(ApexApiResult.Result.SUCCESS, result.getResult());
@@ -173,7 +174,7 @@ public class ApexEditorApiEventTest {
 
         result = apexModel.deleteEventPar("@££%%%", "0.0.2", "NewPar04");
         assertEquals(ApexApiResult.Result.FAILED, result.getResult());
-        result = apexModel.deleteEventPar("NonExistantEvent", "0.0.2", "NewPar04");
+        result = apexModel.deleteEventPar("NonExistentEvent", "0.0.2", "NewPar04");
         assertEquals(ApexApiResult.Result.CONCEPT_DOES_NOT_EXIST, result.getResult());
         assertEquals(4, apexModel.listEventPar("MyEvent002", null, null).getMessages().size());
         result = apexModel.deleteEventPar("MyEvent002", "0.0.2", "NewPar04");
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiKeyInfoTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiKeyInfoTest.java
index 2519b8cb2..831f81503 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiKeyInfoTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiKeyInfoTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,18 +21,18 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Key information for API tests.
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiKeyInfoTest {
+class ApexEditorApiKeyInfoTest {
 
     @Test
-    public void testKeyInfoCrud() {
+    void testKeyInfoCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validateKeyInformation(null, null);
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiPolicyTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiPolicyTest.java
index 0a4d72214..cdc035d8d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiPolicyTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiPolicyTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,18 +21,19 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test policies for API.
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiPolicyTest {
+class ApexEditorApiPolicyTest {
+
     @Test
-    public void testMyTestPolicyCrud() {
+    void testMyTestPolicyCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validatePolicy(null, null);
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiTaskTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiTaskTest.java
index 15e53f925..b0a727138 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiTaskTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexEditorApiTaskTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,9 +22,9 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.modelapi.impl.ApexModelImpl;
 
 /**
@@ -32,9 +32,10 @@ import org.onap.policy.apex.model.modelapi.impl.ApexModelImpl;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexEditorApiTaskTest {
+class ApexEditorApiTaskTest {
+
     @Test
-    public void testTaskCrud() {
+    void testTaskCrud() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.validateTask(null, null);
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexModelApiTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexModelApiTest.java
index f28d0e634..dbd4615b6 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexModelApiTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ApexModelApiTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,18 +22,18 @@
 package org.onap.policy.apex.model.modelapi;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.File;
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.util.UUID;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.modelapi.impl.ApexModelImpl;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
@@ -42,23 +42,23 @@ import org.onap.policy.common.utils.resources.TextFileUtils;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ApexModelApiTest {
+class ApexModelApiTest {
     private Connection connection;
 
-    @Before
-    public void setup() throws Exception {
+    @BeforeEach
+    void setup() throws Exception {
         // Hold the h2 database up for entire tests
         connection = DriverManager.getConnection("jdbc:h2:mem:testdb");
     }
 
-    @After
-    public void teardown() throws Exception {
+    @AfterEach
+    void teardown() throws Exception {
         // Close the h2 database after tests
         connection.close();
     }
 
     @Test
-    public void testApexModelLoadFromFile() {
+    void testApexModelLoadFromFile() {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.loadFromFile("src/main/resources/models/PolicyModel.json");
@@ -82,7 +82,7 @@ public class ApexModelApiTest {
     }
 
     @Test
-    public void testApexModelSaveToFile() throws IOException {
+    void testApexModelSaveToFile() throws IOException {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = apexModel.loadFromFile("src/test/resources/models/PolicyModel.json");
@@ -108,7 +108,7 @@ public class ApexModelApiTest {
     }
 
     @Test
-    public void testApexModelUrl() throws IOException {
+    void testApexModelUrl() throws IOException {
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
 
         assertThatThrownBy(() -> apexModel.readFromUrl(null)).isInstanceOf(IllegalArgumentException.class);
@@ -143,7 +143,7 @@ public class ApexModelApiTest {
     }
 
     @Test
-    public void testApexModelMisc() throws IOException {
+    void testApexModelMisc() throws IOException {
         final ApexModelImpl apexModelImpl = (ApexModelImpl) new ApexModelFactory().createApexModel(null);
 
         ApexApiResult result = null;
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelFacadeTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelFacadeTest.java
index d3b32b923..8569f969d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelFacadeTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelFacadeTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,18 +22,18 @@
 package org.onap.policy.apex.model.modelapi;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.Properties;
 import java.util.UUID;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.modelapi.impl.ModelFacade;
 
-public class ModelFacadeTest {
+class ModelFacadeTest {
 
     @Test
-    public void testModelFacade() {
+    void testModelFacade() {
         assertThatThrownBy(() -> new ModelFacade(null, null))
             .hasMessage("apexModel may not be null");
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelHandlerFacadeTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelHandlerFacadeTest.java
index 5bbc95992..e1675be12 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelHandlerFacadeTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/ModelHandlerFacadeTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,13 +22,13 @@
 package org.onap.policy.apex.model.modelapi;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.File;
 import java.io.IOException;
 import java.util.Properties;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.modelapi.impl.ModelHandlerFacade;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
@@ -37,10 +37,10 @@ import org.onap.policy.common.utils.resources.TextFileUtils;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ModelHandlerFacadeTest {
+class ModelHandlerFacadeTest {
 
     @Test
-    public void testModelHandlerFacade() throws IOException {
+    void testModelHandlerFacade() throws IOException {
         assertThatThrownBy(() -> new ModelHandlerFacade(null, null))
             .hasMessage("apexModel may not be null");
         final ApexModel apexModel = new ApexModelFactory().createApexModel(null);
diff --git a/model/src/test/java/org/onap/policy/apex/model/modelapi/RealModelTest.java b/model/src/test/java/org/onap/policy/apex/model/modelapi/RealModelTest.java
index d9336bd9e..bf84350fd 100644
--- a/model/src/test/java/org/onap/policy/apex/model/modelapi/RealModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/modelapi/RealModelTest.java
@@ -1,6 +1,6 @@
 /*-
  * ============LICENSE_START=======================================================
- *  Copyright (C) 2022 Nordix Foundation.
+ *  Copyright (C) 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,18 +20,18 @@
 
 package org.onap.policy.apex.model.modelapi;
 
-import static org.junit.Assert.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.handling.ApexModelReader;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
-public class RealModelTest {
-    @Test
-    public void testRealModel() throws Exception {
+class RealModelTest {
 
+    @Test
+    void testRealModel() throws Exception {
         final String modelString = TextFileUtils.getTextFileAsString("src/test/resources/models/PolicyModel.json");
 
         AxPolicyModel policyModel = new ApexModelReader<AxPolicyModel>(AxPolicyModel.class).read(modelString);
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/ExceptionsTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/ExceptionsTest.java
index 0afb48b3c..9b1e64a4b 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/ExceptionsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/ExceptionsTest.java
@@ -1,39 +1,41 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.policymodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test model exceptions.
+ *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class ExceptionsTest {
+class ExceptionsTest {
 
     @Test
-    public void test() {
+    void test() {
         assertNotNull(new PolicyException("Message"));
         assertNotNull(new PolicyException("Message", new IOException()));
 
@@ -44,8 +46,8 @@ public class ExceptionsTest {
         assertNotNull(new PolicyRuntimeException("Message", new IOException()));
 
         final PolicyRuntimeException re =
-                new PolicyRuntimeException("Runtime Message", new IOException("IO runtime exception message"));
+            new PolicyRuntimeException("Runtime Message", new IOException("IO runtime exception message"));
         assertEquals("Runtime Message\ncaused by: Runtime Message\ncaused by: IO runtime exception message",
-                re.getCascadedMessage());
+            re.getCascadedMessage());
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/LogicTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/LogicTest.java
index fbfc7c4a0..fd6d33064 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/LogicTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/LogicTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,11 +22,11 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -37,10 +37,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class LogicTest {
+class LogicTest {
 
     @Test
-    public void testLogic() {
+    void testLogic() {
         final DummyLogicReader logicReader = new DummyLogicReader();
 
         assertNotNull(new AxLogic());
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PoliciesTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PoliciesTest.java
index 526f5a628..3fe7d010e 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PoliciesTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PoliciesTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,13 +22,13 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.Map;
 import java.util.TreeMap;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
@@ -41,10 +41,10 @@ import org.onap.policy.apex.model.policymodel.handling.SupportApexPolicyModelCre
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class PoliciesTest {
+class PoliciesTest {
 
     @Test
-    public void testPolicies() {
+    void testPolicies() {
         final TreeMap<String, AxState> stateMap = new TreeMap<>();
         final TreeMap<String, AxState> stateMapEmpty = new TreeMap<>();
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PolicyModelTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PolicyModelTest.java
index b699b5d48..b04757714 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PolicyModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/PolicyModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,11 +22,11 @@
 
 package org.onap.policy.apex.model.policymodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
@@ -44,10 +44,10 @@ import org.onap.policy.apex.model.policymodel.handling.SupportApexPolicyModelCre
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class PolicyModelTest {
+class PolicyModelTest {
 
     @Test
-    public void testPolicyModel() {
+    void testPolicyModel() {
         assertNotNull(new AxPolicyModel());
         assertNotNull(new AxPolicyModel(new AxArtifactKey()));
         assertNotNull(new AxPolicyModel(new AxArtifactKey(), new AxContextSchemas(), new AxKeyInformation(),
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateOutputTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateOutputTest.java
index 049783a7f..b2cf1f27c 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateOutputTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateOutputTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,11 +23,11 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -38,10 +38,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class StateOutputTest {
+class StateOutputTest {
 
     @Test
-    public void testStateOutput() {
+    void testStateOutput() {
         assertNotNull(new AxStateOutput());
         assertNotNull(new AxStateOutput(new AxReferenceKey()));
         assertNotNull(new AxStateOutput(new AxReferenceKey(), new AxReferenceKey(), new AxArtifactKey()));
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTaskReferenceTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTaskReferenceTest.java
index 568c47f61..078fd6f52 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTaskReferenceTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTaskReferenceTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,11 +22,11 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -37,10 +37,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class StateTaskReferenceTest {
+class StateTaskReferenceTest {
 
     @Test
-    public void testStateTaskReference() {
+    void testStateTaskReference() {
         assertNotNull(new AxStateTaskReference());
         assertNotNull(new AxStateTaskReference(new AxReferenceKey()));
         assertNotNull(new AxStateTaskReference(new AxReferenceKey(), AxStateTaskOutputType.UNDEFINED,
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTest.java
index 7fbe78078..d5f5899fc 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/StateTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,14 +22,14 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
@@ -41,10 +41,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class StateTest {
+class StateTest {
 
     @Test
-    public void testState() {
+    void testState() {
         final TreeMap<String, AxStateOutput> soEmptyMap = new TreeMap<>();
         final TreeSet<AxArtifactKey> ctxtEmptySet = new TreeSet<>();
         final TreeMap<String, AxStateFinalizerLogic> sflEmptyMap = new TreeMap<>();
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TaskParameterTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TaskParameterTest.java
index 4255b495d..25eb774fa 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TaskParameterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TaskParameterTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,11 +22,11 @@
 package org.onap.policy.apex.model.policymodel.concepts;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -37,10 +37,10 @@ import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult.Validat
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class TaskParameterTest {
+class TaskParameterTest {
 
     @Test
-    public void testTaskParameter() {
+    void testTaskParameter() {
         assertNotNull(new AxTaskParameter());
         assertNotNull(new AxTaskParameter(new AxReferenceKey()));
         assertNotNull(new AxTaskParameter(new AxReferenceKey(), "DefaultValue"));
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TasksTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TasksTest.java
index 9c7866c85..519e21e2b 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TasksTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/concepts/TasksTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019-2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2019-2020, 2022, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,14 +22,14 @@
 
 package org.onap.policy.apex.model.policymodel.concepts;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.Map;
 import java.util.TreeMap;
 import java.util.TreeSet;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
@@ -41,10 +41,10 @@ import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class TasksTest {
+class TasksTest {
 
     @Test
-    public void testTasks() {
+    void testTasks() {
         final TreeMap<String, AxTaskParameter> tpEmptyMap = new TreeMap<>();
         final TreeSet<AxArtifactKey> ctxtEmptySet = new TreeSet<>();
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/ApexPolicyModelTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/ApexPolicyModelTest.java
index 48e4f87f9..01f7062e1 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/ApexPolicyModelTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/ApexPolicyModelTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,72 +22,23 @@
 
 package org.onap.policy.apex.model.policymodel.handling;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
 import org.onap.policy.apex.model.basicmodel.test.TestApexModel;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
+import org.onap.policy.common.utils.resources.ResourceUtils;
 
-public class ApexPolicyModelTest {
+class ApexPolicyModelTest {
     private static final String VALID_MODEL_STRING = "***validation of model successful***";
 
-    private static final String OBSERVATION_MODEL_STRING = "\n"
-                    + "***observations noted during validation of model***\n"
-                    + "AxReferenceKey:(parentKeyName=policy,parentKeyVersion=0.0.1,parentLocalName=NULL,"
-                    + "localName=state):org.onap.policy.apex.model.policymodel.concepts.AxState:OBSERVATION:"
-                    + "state output stateOutput0 is not used directly by any task\n"
-                    + "********************************";
-
-    private static final String WARNING_MODEL_STRING = "\n" + "***warnings issued during validation of model***\n"
-                    + "AxArtifactKey:(name=policy,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicy:WARNING:state AxReferenceKey:"
-                    + "(parentKeyName=policy,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=anotherState) "
-                    + "is not referenced in the policy execution tree\n" + "********************************";
-
-    private static final String INVALID_MODEL_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=contextAlbum0,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:scope is not defined\n"
-                    + "AxArtifactKey:(name=contextAlbum1,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:scope is not defined\n"
-                    + "********************************";
-
-    private static final String INVALID_MODEL_MALSTRUCTURED_STRING = "\n" + "***validation of model failed***\n"
-                    + "AxArtifactKey:(name=policyModel_KeyInfo,version=0.0.1):"
-                    + "org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:"
-                    + "keyInfoMap may not be empty\n" + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_KeyInfo,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_Schemas,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_Events,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_Albums,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_Tasks,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:"
-                    + "key information not found for key AxArtifactKey:(name=policyModel_Policies,version=0.0.1)\n"
-                    + "AxArtifactKey:(name=policyModel_Schemas,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas:INVALID:"
-                    + "contextSchemas may not be empty\n" + "AxArtifactKey:(name=policyModel_Events,version=0.0.1):"
-                    + "org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:eventMap may not be empty\n"
-                    + "AxArtifactKey:(name=policyModel_Albums,version=0.0.1):"
-                    + "org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbums:OBSERVATION:albums are empty\n"
-                    + "AxArtifactKey:(name=policyModel_Tasks,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxTasks:INVALID:taskMap may not be empty\n"
-                    + "AxArtifactKey:(name=policyModel_Policies,version=0.0.1)"
-                    + ":org.onap.policy.apex.model.policymodel.concepts.AxPolicies:INVALID:policyMap may not be empty\n"
-                    + "********************************";
+    private static final String OBSERVATION_MODEL_STRING = "policymodel/handling/ApexPolicyModel_ObservationModel.txt";
+    private static final String WARNING_MODEL_STRING = "policymodel/handling/ApexPolicyModel_WarningModel.txt";
+    private static final String INVALID_MODEL_STRING = "policymodel/handling/ApexPolicyModelTest_InvalidModel.txt";
+    private static final String INVALID_MODEL_MALSTRUCTURED_STRING =
+        "policymodel/handling/ApexPolicyModelTest_InvalidMalStructuredModel.txt";
 
     TestApexModel<AxPolicyModel> testApexModel;
 
@@ -96,43 +47,43 @@ public class ApexPolicyModelTest {
      *
      * @throws Exception on setup errors
      */
-    @Before
+    @BeforeEach
     public void setup() throws Exception {
-        testApexModel = new TestApexModel<AxPolicyModel>(AxPolicyModel.class, new SupportApexPolicyModelCreator());
+        testApexModel = new TestApexModel<>(AxPolicyModel.class, new SupportApexPolicyModelCreator());
     }
 
     @Test
-    public void testModelValid() throws Exception {
+    void testModelValid() throws Exception {
         final AxValidationResult result = testApexModel.testApexModelValid();
         assertEquals(VALID_MODEL_STRING, result.toString());
     }
 
     @Test
-    public void testApexModelVaidateObservation() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateObservation();
-        assertEquals(OBSERVATION_MODEL_STRING, result.toString());
+    void testApexModelValidateObservation() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateObservation();
+        assertEquals(ResourceUtils.getResourceAsString(OBSERVATION_MODEL_STRING), result.toString());
     }
 
     @Test
-    public void testApexModelVaidateWarning() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateWarning();
-        assertEquals(WARNING_MODEL_STRING, result.toString());
+    void testApexModelValidateWarning() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateWarning();
+        assertEquals(ResourceUtils.getResourceAsString(WARNING_MODEL_STRING), result.toString());
     }
 
     @Test
-    public void testModelVaidateInvalidModel() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateInvalidModel();
-        assertEquals(INVALID_MODEL_STRING, result.toString());
+    void testModelValidateInvalidModel() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateInvalidModel();
+        assertEquals(ResourceUtils.getResourceAsString(INVALID_MODEL_STRING), result.toString());
     }
 
     @Test
-    public void testModelVaidateMalstructured() throws Exception {
-        final AxValidationResult result = testApexModel.testApexModelVaidateMalstructured();
-        assertEquals(INVALID_MODEL_MALSTRUCTURED_STRING, result.toString());
+    void testModelValidateMalstructured() throws Exception {
+        final AxValidationResult result = testApexModel.testApexModelValidateMalstructured();
+        assertEquals(ResourceUtils.getResourceAsString(INVALID_MODEL_MALSTRUCTURED_STRING), result.toString());
     }
 
     @Test
-    public void testModelWriteReadJson() throws Exception {
+    void testModelWriteReadJson() throws Exception {
         testApexModel.testApexModelWriteReadJson();
     }
 }
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyAnalyserTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyAnalyserTest.java
index b1e2d5cbd..a3e1859a9 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyAnalyserTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyAnalyserTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -22,15 +22,15 @@
 
 package org.onap.policy.apex.model.policymodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
 
-public class PolicyAnalyserTest {
+class PolicyAnalyserTest {
     @Test
-    public void test() {
+    void test() {
         final AxPolicyModel apexModel = new SupportApexPolicyModelCreator().getModel();
 
         final PolicyAnalyser policyAnalyser = new PolicyAnalyser();
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyLogicReaderTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyLogicReaderTest.java
index a2cbe7415..b9885e39d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyLogicReaderTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyLogicReaderTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,9 +23,9 @@ package org.onap.policy.apex.model.policymodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.policymodel.concepts.AxLogic;
@@ -35,10 +35,10 @@ import org.onap.policy.apex.model.policymodel.concepts.AxLogic;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class PolicyLogicReaderTest {
+class PolicyLogicReaderTest {
 
     @Test
-    public void test() {
+    void test() {
         final AxReferenceKey logicKey = new AxReferenceKey("LogicParent", "0.0.1", "LogicInstanceName");
 
         final PolicyLogicReader plReader = new PolicyLogicReader();
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelComparerTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelComparerTest.java
index 691880d6b..ea3bc5564 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelComparerTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelComparerTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020,2022 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2022, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,21 +21,21 @@
 
 package org.onap.policy.apex.model.policymodel.handling;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.IOException;
 import java.util.UUID;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
-public class PolicyModelComparerTest {
+class PolicyModelComparerTest {
 
     @Test
-    public void testPolicyComparer() throws IOException {
+    void testPolicyComparer() throws IOException {
         final AxPolicyModel leftApexModel = new SupportApexPolicyModelCreator().getModel();
         final AxPolicyModel rightApexModel = new AxPolicyModel(leftApexModel);
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelMergerTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelMergerTest.java
index 2bdf7499f..0625068cf 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelMergerTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelMergerTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2019 Nordix Foundation.
+ *  Modifications Copyright (C) 2019, 2024 Nordix Foundation.
  *  Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,10 +23,10 @@
 package org.onap.policy.apex.model.policymodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.handling.ApexModelException;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
@@ -37,10 +37,10 @@ import org.onap.policy.apex.model.policymodel.concepts.AxTaskLogic;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class PolicyModelMergerTest {
+class PolicyModelMergerTest {
 
     @Test
-    public void testPolicyModelMerger() throws ApexModelException {
+    void testPolicyModelMerger() throws ApexModelException {
         final AxPolicyModel leftPolicyModel = new SupportApexPolicyModelCreator().getModel();
         final AxPolicyModel rightPolicyModel = new SupportApexPolicyModelCreator().getModel();
 
diff --git a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelSplitterTest.java b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelSplitterTest.java
index 902206d51..070b29ff2 100644
--- a/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelSplitterTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/policymodel/handling/PolicyModelSplitterTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,19 +22,19 @@
 package org.onap.policy.apex.model.policymodel.handling;
 
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.Set;
 import java.util.TreeSet;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.handling.ApexModelException;
 import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
 
-public class PolicyModelSplitterTest {
+class PolicyModelSplitterTest {
     @Test
-    public void test() throws ApexModelException {
+    void test() throws ApexModelException {
         final AxPolicyModel apexModel = new SupportApexPolicyModelCreator().getModel();
 
         final Set<AxArtifactKey> requiredPolicySet = new TreeSet<AxArtifactKey>();
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/CollectionUtilitiesTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/CollectionUtilitiesTest.java
index 2512133e7..5b75e3202 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/CollectionUtilitiesTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/CollectionUtilitiesTest.java
@@ -1,46 +1,47 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.utilities;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
 import java.util.List;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-public class CollectionUtilitiesTest {
+class CollectionUtilitiesTest {
 
     @Test
-    public void testNullLists() {
-        int result = 0;
+    void testNullLists() {
+        int result;
 
         result = CollectionUtils.compareLists(null, null);
         assertEquals(0, result);
 
-        List<String> leftList = new ArrayList<String>();
+        List<String> leftList = new ArrayList<>();
 
         result = CollectionUtils.compareLists(leftList, null);
         assertEquals(-1, result);
 
-        List<String> rightList = new ArrayList<String>();
+        List<String> rightList = new ArrayList<>();
 
         result = CollectionUtils.compareLists(null, rightList);
         assertEquals(1, result);
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/DirectoryUtilsTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/DirectoryUtilsTest.java
index 69c2d4763..d51ca4c34 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/DirectoryUtilsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/DirectoryUtilsTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,19 +21,19 @@
 
 package org.onap.policy.apex.model.utilities;
 
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.util.Arrays;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
-public class DirectoryUtilsTest {
+class DirectoryUtilsTest {
 
     @Test
-    public void test() throws IOException {
+    void test() throws IOException {
         DirectoryUtils.emptyDirectory(new File("/i/dont/exist"));
 
         File tempDir = Files.createTempDirectory("test").toFile();
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/KeyComparerTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/KeyComparerTest.java
index 20780b271..22c6d659d 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/KeyComparerTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/KeyComparerTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,10 +21,10 @@
 
 package org.onap.policy.apex.model.utilities;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.utilities.comparison.KeyComparer;
 import org.onap.policy.apex.model.utilities.comparison.KeyDifference;
 
@@ -33,15 +33,15 @@ import org.onap.policy.apex.model.utilities.comparison.KeyDifference;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class KeyComparerTest {
+class KeyComparerTest {
 
     @Test
-    public void test() {
+    void test() {
         KeyDifference<String> keyDifference = new KeyComparer<String>().compareKeys("Hello", "Goodbye");
 
         assertFalse(keyDifference.isEqual());
-        assertEquals("Hello", keyDifference.getLeftKey().toString());
-        assertEquals("Goodbye", keyDifference.getRightKey().toString());
+        assertEquals("Hello", keyDifference.getLeftKey());
+        assertEquals("Goodbye", keyDifference.getRightKey());
 
         assertEquals("left key Hello and right key Goodbye differ\n", keyDifference.asString(true));
         assertEquals("left key Hello and right key Goodbye differ\n", keyDifference.asString(false));
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/KeyedMapComparerTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/KeyedMapComparerTest.java
index b4e88e20d..ee473d9f7 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/KeyedMapComparerTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/KeyedMapComparerTest.java
@@ -1,7 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,11 +21,11 @@
 
 package org.onap.policy.apex.model.utilities;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 import java.util.TreeMap;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.apex.model.utilities.comparison.KeyedMapComparer;
 import org.onap.policy.apex.model.utilities.comparison.KeyedMapDifference;
 
@@ -34,10 +34,10 @@ import org.onap.policy.apex.model.utilities.comparison.KeyedMapDifference;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class KeyedMapComparerTest {
+class KeyedMapComparerTest {
 
     @Test
-    public void test() {
+    void test() {
         TreeMap<String, String> leftMap = new TreeMap<String, String>();
         leftMap.put("B", "BBBBB");
         leftMap.put("C", "CCCCC");
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/TextFileUtilsTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/TextFileUtilsTest.java
index 1d6f29fe5..01d849efd 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/TextFileUtilsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/TextFileUtilsTest.java
@@ -1,7 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
- *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2020, 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,12 +21,12 @@
 
 package org.onap.policy.apex.model.utilities;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.onap.policy.common.utils.resources.TextFileUtils;
 
 /**
@@ -34,12 +34,12 @@ import org.onap.policy.common.utils.resources.TextFileUtils;
  *
  * @author Liam Fallon (liam.fallon@ericsson.com)
  */
-public class TextFileUtilsTest {
+class TextFileUtilsTest {
 
     private static final String FILE_CONTENT = "This is the contents of a text file";
 
     @Test
-    public void test() throws IOException {
+    void test() throws IOException {
         final File tempTextFile = File.createTempFile("Test", "txt");
 
         TextFileUtils.putStringAsTextFile(FILE_CONTENT, tempTextFile.getAbsolutePath());
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/TreeMapUtilsTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/TreeMapUtilsTest.java
index c3a36b7b9..296f35d49 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/TreeMapUtilsTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/TreeMapUtilsTest.java
@@ -2,6 +2,7 @@
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
  *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,13 +23,13 @@
 package org.onap.policy.apex.model.utilities;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.TreeMap;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test the tree map utilities.
diff --git a/model/src/test/java/org/onap/policy/apex/model/utilities/json/JsonHandlerTest.java b/model/src/test/java/org/onap/policy/apex/model/utilities/json/JsonHandlerTest.java
index ae5d53ec3..d5c913d91 100644
--- a/model/src/test/java/org/onap/policy/apex/model/utilities/json/JsonHandlerTest.java
+++ b/model/src/test/java/org/onap/policy/apex/model/utilities/json/JsonHandlerTest.java
@@ -1,40 +1,41 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.model.utilities.json;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.google.gson.GsonBuilder;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-public class JsonHandlerTest {
+class JsonHandlerTest {
 
     private static final String VALUE = "value";
 
     @Test
-    public void testAssertions() throws IOException {
+    void testAssertions() throws IOException {
         final OverTheMoonObject jsonObject = new OverTheMoonObject(VALUE);
         final String jsonString = new GsonBuilder().create().toJson(jsonObject);
 
diff --git a/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModel.txt b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModel.txt
new file mode 100644
index 000000000..bb3f256cd
--- /dev/null
+++ b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModel.txt
@@ -0,0 +1,7 @@
+
+***validation of model failed***
+AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000
+AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:OBSERVATION:description is blank
+AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000
+AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:duplicate UUID found on keyInfoMap entry AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):00000000-0000-0000-0000-000000000000
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModelMalStructured.txt b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModelMalStructured.txt
new file mode 100644
index 000000000..c375c13ce
--- /dev/null
+++ b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_InvalidModelMalStructured.txt
@@ -0,0 +1,5 @@
+
+***validation of model failed***
+AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000
+AxArtifactKey:(name=BasicModelKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:INVALID:key information not found for key AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_ValidModel.txt b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_ValidModel.txt
new file mode 100644
index 000000000..ba08a0b02
--- /dev/null
+++ b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_ValidModel.txt
@@ -0,0 +1,5 @@
+
+***warnings issued during validation of model***
+AxArtifactKey:(name=FloatKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+AxArtifactKey:(name=IntegerKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_WarningModel.txt b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_WarningModel.txt
new file mode 100644
index 000000000..0b7ec4af1
--- /dev/null
+++ b/model/src/test/resources/basicmodel/handling/SupportApexBasicModelTest_WarningModel.txt
@@ -0,0 +1,7 @@
+
+***warnings issued during validation of model***
+AxArtifactKey:(name=FloatKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+AxArtifactKey:(name=IntegerKIKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+AxArtifactKey:(name=Unref0,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+AxArtifactKey:(name=Unref1,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxModel:WARNING:key not found for key information entry
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidMalStructuredModel.txt b/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidMalStructuredModel.txt
new file mode 100644
index 000000000..636a22342
--- /dev/null
+++ b/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidMalStructuredModel.txt
@@ -0,0 +1,7 @@
+
+***validation of model failed***
+AxArtifactKey:(name=ContextModel,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextModel:INVALID:key information not found for key AxArtifactKey:(name=contextAlbum1,version=0.0.2)
+AxArtifactKey:(name=contextAlbum1,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextModel:WARNING:key not found for key information entry
+AxArtifactKey:(name=ContextSchemas,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas:INVALID:key on schemas entry AxArtifactKey:(name=MapType,version=0.0.1) does not equal entry key AxArtifactKey:(name=MapType,version=0.0.2)
+AxArtifactKey:(name=contextAlbums,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbums:INVALID:key on context album entry key AxArtifactKey:(name=contextAlbum1,version=0.0.1) does not equal context album value key AxArtifactKey:(name=contextAlbum1,version=0.0.2)
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidModel.txt b/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidModel.txt
new file mode 100644
index 000000000..d6fa068da
--- /dev/null
+++ b/model/src/test/resources/contextmodel/handling/ApexContextModel_InvalidModel.txt
@@ -0,0 +1,5 @@
+
+***validation of model failed***
+AxArtifactKey:(name=StringType,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema:INVALID:no schemaDefinition specified, schemaDefinition may not be blank
+AxArtifactKey:(name=contextAlbum0,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:scope is not defined
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/contextmodel/handling/ApexContextModel_ObservationModel.txt b/model/src/test/resources/contextmodel/handling/ApexContextModel_ObservationModel.txt
new file mode 100644
index 000000000..cf27f0a80
--- /dev/null
+++ b/model/src/test/resources/contextmodel/handling/ApexContextModel_ObservationModel.txt
@@ -0,0 +1,4 @@
+
+***observations noted during validation of model***
+AxArtifactKey:(name=contextAlbum1,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:OBSERVATION:description is blank
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/contextmodel/handling/ApexContextModel_WarningModel.txt b/model/src/test/resources/contextmodel/handling/ApexContextModel_WarningModel.txt
new file mode 100644
index 000000000..f8b177b0a
--- /dev/null
+++ b/model/src/test/resources/contextmodel/handling/ApexContextModel_WarningModel.txt
@@ -0,0 +1,4 @@
+
+***warnings issued during validation of model***
+AxArtifactKey:(name=contextAlbum1,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInfo:WARNING:UUID is a zero UUID: 00000000-0000-0000-0000-000000000000
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModel.txt b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModel.txt
new file mode 100644
index 000000000..53a398363
--- /dev/null
+++ b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModel.txt
@@ -0,0 +1,37 @@
+
+***validation of model failed***
+AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:keyInfoMap may not be empty
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=smallEventModel,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=Schemas,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=BigIntType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=BooleanType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=IntType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=MapType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=SetType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=StringType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=smallEventMap,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=event0,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par0)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par2)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par3)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par4)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par5)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=par6)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:duplicate key AxArtifactKey:(name=event1,version=0.0.1) found
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:duplicate key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar) found
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:INVALID:parent key on parameter field AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar) does not equal event key
+AxArtifactKey:(name=smallEventMap,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:key on event entry key AxArtifactKey:(name=event2,version=0.0.1) does not equal event value key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:INVALID:parent key on parameter field AxReferenceKey:(parentKeyName=event0,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar) does not equal event key
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModelMalStructured.txt b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModelMalStructured.txt
new file mode 100644
index 000000000..5c94674d4
--- /dev/null
+++ b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_InvalidModelMalStructured.txt
@@ -0,0 +1,20 @@
+
+***validation of model failed***
+AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:keyInfoMap may not be empty
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=smallEventModel,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=KeyInfoMapKey,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=Schemas,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=SetType,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=smallEventMap,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event1,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:duplicate key AxArtifactKey:(name=event1,version=0.0.1) found
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:duplicate key AxReferenceKey:(parentKeyName=event1,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar) found
+AxArtifactKey:(name=smallEventModel,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEventModel:INVALID:key information not found for parent key of key AxReferenceKey:(parentKeyName=event1,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=theOnlyPar)
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=smallEventMap,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:key on event entry key AxArtifactKey:(name=event2,version=0.0.1) does not equal event value key AxArtifactKey:(name=event1,version=0.0.1)
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/eventmodel/handling/ApexEventModelTest_ObservationModel.txt b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_ObservationModel.txt
new file mode 100644
index 000000000..8d2321df1
--- /dev/null
+++ b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_ObservationModel.txt
@@ -0,0 +1,9 @@
+
+***observations noted during validation of model***
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event2,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event2,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/eventmodel/handling/ApexEventModelTest_WarningModel.txt b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_WarningModel.txt
new file mode 100644
index 000000000..8c17042cf
--- /dev/null
+++ b/model/src/test/resources/eventmodel/handling/ApexEventModelTest_WarningModel.txt
@@ -0,0 +1,12 @@
+
+***warnings issued during validation of model***
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event0,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event1,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+AxArtifactKey:(name=event2,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:WARNING:nameSpace on event is blank
+AxArtifactKey:(name=event2,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:source on event is blank
+AxArtifactKey:(name=event2,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvent:OBSERVATION:target on event is blank
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidMalStructuredModel.txt b/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidMalStructuredModel.txt
new file mode 100644
index 000000000..0a57a46e4
--- /dev/null
+++ b/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidMalStructuredModel.txt
@@ -0,0 +1,16 @@
+
+***validation of model failed***
+AxArtifactKey:(name=policyModel_KeyInfo,version=0.0.1):org.onap.policy.apex.model.basicmodel.concepts.AxKeyInformation:INVALID:keyInfoMap may not be empty
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_KeyInfo,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_Schemas,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_Events,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_Albums,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_Tasks,version=0.0.1)
+AxArtifactKey:(name=policyModel,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel:INVALID:key information not found for key AxArtifactKey:(name=policyModel_Policies,version=0.0.1)
+AxArtifactKey:(name=policyModel_Schemas,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas:INVALID:contextSchemas may not be empty
+AxArtifactKey:(name=policyModel_Events,version=0.0.1):org.onap.policy.apex.model.eventmodel.concepts.AxEvents:INVALID:eventMap may not be empty
+AxArtifactKey:(name=policyModel_Albums,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbums:OBSERVATION:albums are empty
+AxArtifactKey:(name=policyModel_Tasks,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxTasks:INVALID:taskMap may not be empty
+AxArtifactKey:(name=policyModel_Policies,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicies:INVALID:policyMap may not be empty
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidModel.txt b/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidModel.txt
new file mode 100644
index 000000000..c3a0ad78d
--- /dev/null
+++ b/model/src/test/resources/policymodel/handling/ApexPolicyModelTest_InvalidModel.txt
@@ -0,0 +1,5 @@
+
+***validation of model failed***
+AxArtifactKey:(name=contextAlbum0,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:scope is not defined
+AxArtifactKey:(name=contextAlbum1,version=0.0.1):org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum:INVALID:scope is not defined
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/policymodel/handling/ApexPolicyModel_ObservationModel.txt b/model/src/test/resources/policymodel/handling/ApexPolicyModel_ObservationModel.txt
new file mode 100644
index 000000000..43a1cc530
--- /dev/null
+++ b/model/src/test/resources/policymodel/handling/ApexPolicyModel_ObservationModel.txt
@@ -0,0 +1,4 @@
+
+***observations noted during validation of model***
+AxReferenceKey:(parentKeyName=policy,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=state):org.onap.policy.apex.model.policymodel.concepts.AxState:OBSERVATION:state output stateOutput0 is not used directly by any task
+********************************
\ No newline at end of file
diff --git a/model/src/test/resources/policymodel/handling/ApexPolicyModel_WarningModel.txt b/model/src/test/resources/policymodel/handling/ApexPolicyModel_WarningModel.txt
new file mode 100644
index 000000000..79c5c310a
--- /dev/null
+++ b/model/src/test/resources/policymodel/handling/ApexPolicyModel_WarningModel.txt
@@ -0,0 +1,4 @@
+
+***warnings issued during validation of model***
+AxArtifactKey:(name=policy,version=0.0.1):org.onap.policy.apex.model.policymodel.concepts.AxPolicy:WARNING:state AxReferenceKey:(parentKeyName=policy,parentKeyVersion=0.0.1,parentLocalName=NULL,localName=anotherState) is not referenced in the policy execution tree
+********************************
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 0927ebb9c..67db076e3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -28,7 +28,7 @@
         <groupId>org.onap.policy.parent</groupId>
         <artifactId>integration</artifactId>
         <version>5.0.0-SNAPSHOT</version>
-        <relativePath />
+        <relativePath/>
     </parent>
 
     <groupId>org.onap.policy.apex-pdp</groupId>
@@ -88,6 +88,26 @@
             <scope>test</scope>
         </dependency>
         <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
         </dependency>