Remove apex-pdp unused core modules

This is the final review in the refactoring of the model code in
apex-pdp.

The core-messaging and core-infrastructure modules are unused in
apex-pdp except for websocket communication. Websocket communication is
also not used in any deployment.

This review:
- removes the core-mesaging module, which had an apex-specific websocket
  implementation, except for the MessageException class, which is moved
  to the base core module
- removes the core-infrastructure module, except for the ThreadUtils
  class, which is moved to the base core module
- removes the websocket event protocol, which used core-messaging but is
  not used in any deployment
- collapses all three "core" submodules into a single module
- Updates dependencies where needed

Issue-ID: POLICY-1820
Change-Id: Ieae30063e99570e61943372d3fa23b77a211462c
Signed-off-by: liamfallon <liam.fallon@est.tech>

30 files changed, 3872 insertions, 0 deletions

diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/EngineParametersTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/EngineParametersTest.java
new file mode 100644
index 000000000..5427c3515
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/EngineParametersTest.java
@@ -0,0 +1,94 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import org.junit.Test;
+import org.onap.policy.apex.context.parameters.ContextParameters;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the executor parameters.
+ *
+ */
+public class EngineParametersTest {
+
+    @Test
+    public void test() {
+        EngineParameters pars = new EngineParameters();
+        pars.setName("Name");
+        assertEquals("Name", pars.getName());
+
+        ContextParameters contextPars = new ContextParameters();
+
+        pars.setContextParameters(contextPars);
+        assertEquals(contextPars, pars.getContextParameters());
+
+        Map<String, ExecutorParameters> executorParameterMap = new LinkedHashMap<>();
+        executorParameterMap.put("Executor", new ExecutorParameters());
+        pars.setExecutorParameterMap(executorParameterMap);
+        assertEquals(executorParameterMap, pars.getExecutorParameterMap());
+
+        List<TaskParameters> taskParameters = new ArrayList<>();
+        taskParameters.add(new TaskParameters("param1key", "param1value", "param1taskId"));
+        taskParameters.add(new TaskParameters("param1key", "param1value", null));
+        pars.setTaskParameters(taskParameters);
+
+        assertThat(pars.validate().getResult()).isNull();
+        assertTrue(pars.validate().isValid());
+
+        ParameterService.register(pars);
+        ParameterService.deregister(pars);
+    }
+
+    @Test
+    public void test_invalid() {
+        EngineParameters pars = new EngineParameters();
+        pars.setName("Name");
+        assertEquals("Name", pars.getName());
+
+        ContextParameters contextPars = new ContextParameters();
+
+        pars.setContextParameters(contextPars);
+        assertEquals(contextPars, pars.getContextParameters());
+
+        Map<String, ExecutorParameters> executorParameterMap = Map.of("Executor", new ExecutorParameters());
+        pars.setExecutorParameterMap(executorParameterMap);
+        assertEquals(executorParameterMap, pars.getExecutorParameterMap());
+
+        pars.setTaskParameters(List.of(new TaskParameters(null, "param1value", "param1taskId")));
+        assertFalse(pars.validate().isValid());
+        pars.setTaskParameters(List.of(new TaskParameters(" ", "param1value", "param1taskId")));
+        assertFalse(pars.validate().isValid());
+        pars.setTaskParameters(List.of(new TaskParameters("param1key", "", "param1taskId")));
+        assertFalse(pars.validate().isValid());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/ExecutorParametersTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/ExecutorParametersTest.java
new file mode 100644
index 000000000..784580422
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/ExecutorParametersTest.java
@@ -0,0 +1,60 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the executor parameters.
+ *
+ */
+public class ExecutorParametersTest {
+
+    @Test
+    public void test() {
+        ExecutorParameters pars = new ExecutorParameters();
+        pars.setName("Name");
+        assertEquals("Name", pars.getName());
+        pars.setStateFinalizerExecutorPluginClass("some.state.finalizer.plugin.class");
+        assertEquals("some.state.finalizer.plugin.class", pars.getStateFinalizerExecutorPluginClass());
+        pars.setTaskExecutorPluginClass("some.task.executor.plugin.class");
+        assertEquals("some.task.executor.plugin.class", pars.getTaskExecutorPluginClass());
+        pars.setTaskSelectionExecutorPluginClass("some.task.selection.executor.plugin.class");
+        assertEquals("some.task.selection.executor.plugin.class", pars.getTaskSelectionExecutorPluginClass());
+
+        assertEquals("ExecutorParameters [name=Name, taskExecutorPluginClass=some.task.executor.plugin.class, "
+                        + "taskSelectionExecutorPluginClass=some.task.selection.executor.plugin.class, "
+                        + "stateFinalizerExecutorPluginClass=some.state.finalizer.plugin.class]", pars.toString());
+
+        assertThat(pars.validate().getResult()).isNull();
+        assertTrue(pars.validate().isValid());
+
+
+        ParameterService.register(pars);
+        ParameterService.deregister(pars);
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java
new file mode 100644
index 000000000..19828f6e2
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java
@@ -0,0 +1,174 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019-2020 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.core.engine.context;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.context.parameters.ContextParameterConstants;
+import org.onap.policy.apex.context.parameters.DistributorParameters;
+import org.onap.policy.apex.context.parameters.LockManagerParameters;
+import org.onap.policy.apex.context.parameters.PersistorParameters;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+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.AxContextSchema;
+import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the Apex engine internal context class.
+ */
+public class ApexInternalContextTest {
+
+    private AxPolicyModel policyModel;
+    private AxPolicyModel newVersionPolicyModel;
+    private AxPolicyModel newPolicyModel;
+    private AxContextAlbum album;
+    private AxContextAlbum newAlbum;
+    private AxPolicyModel incompatiblePolicyModel;
+
+    /**
+     * Initialize parameters.
+     */
+    @Before
+    public void registerParameters() {
+        ParameterService.register(new SchemaParameters());
+        ParameterService.register(new DistributorParameters());
+        ParameterService.register(new LockManagerParameters());
+        ParameterService.register(new PersistorParameters());
+    }
+
+    /**
+     * Create policy model.
+     */
+    @Before
+    public void createPolicyModels() {
+        AxArtifactKey modelKey = new AxArtifactKey("PolicyModel:0.0.1");
+        policyModel = new AxPolicyModel(modelKey);
+
+        AxArtifactKey schemaKey = new AxArtifactKey("Schema:0.0.1");
+        AxContextSchema schema = new AxContextSchema(schemaKey, "Java", "java.lang.String");
+        policyModel.getSchemas().getSchemasMap().put(schemaKey, schema);
+
+        AxArtifactKey albumKey = new AxArtifactKey("Album:0.0.1");
+        album = new AxContextAlbum(albumKey, "Policy", true, schemaKey);
+
+        policyModel.getAlbums().getAlbumsMap().put(albumKey, album);
+
+        AxArtifactKey newVersionModelKey = new AxArtifactKey("PolicyModel:0.0.2");
+        newVersionPolicyModel = new AxPolicyModel(newVersionModelKey);
+
+        newVersionPolicyModel.getSchemas().getSchemasMap().put(schemaKey, schema);
+        AxContextAlbum compatibleAlbum = new AxContextAlbum(albumKey, "Global", true, schemaKey);
+        newVersionPolicyModel.getAlbums().getAlbumsMap().put(albumKey, compatibleAlbum);
+
+        AxArtifactKey anotherAlbumKey = new AxArtifactKey("AnotherAlbum:0.0.1");
+        AxContextAlbum anotherAlbum = new AxContextAlbum(anotherAlbumKey, "Policy", true, schemaKey);
+
+        newVersionPolicyModel.getAlbums().getAlbumsMap().put(anotherAlbumKey, anotherAlbum);
+
+        AxArtifactKey incompatibleModelKey = new AxArtifactKey("IncompatiblePolicyModel:0.0.2");
+        incompatiblePolicyModel = new AxPolicyModel(incompatibleModelKey);
+
+        AxArtifactKey incompatibleSchemaKey = new AxArtifactKey("IncompatibleSchema:0.0.1");
+        AxContextSchema incompatibleSchema = new AxContextSchema(incompatibleSchemaKey, "Java", "java.lang.Integer");
+        incompatiblePolicyModel.getSchemas().getSchemasMap().put(incompatibleSchemaKey, incompatibleSchema);
+
+        AxContextAlbum incompatibleAlbum = new AxContextAlbum(albumKey, "Policy", true, incompatibleSchemaKey);
+        incompatiblePolicyModel.getAlbums().getAlbumsMap().put(albumKey, incompatibleAlbum);
+
+        AxArtifactKey newModelKey = new AxArtifactKey("NewPolicyModel:0.0.1");
+        newPolicyModel = new AxPolicyModel(newModelKey);
+
+        AxArtifactKey newSchemaKey = new AxArtifactKey("NewSchema:0.0.1");
+        AxContextSchema newSchema = new AxContextSchema(newSchemaKey, "Java", "java.lang.Integer");
+        newPolicyModel.getSchemas().getSchemasMap().put(newSchemaKey, newSchema);
+
+        AxArtifactKey newAlbumKey = new AxArtifactKey("NewAlbum:0.0.1");
+        newAlbum = new AxContextAlbum(newAlbumKey, "Policy", true, newSchemaKey);
+
+        newPolicyModel.getAlbums().getAlbumsMap().put(newAlbumKey, newAlbum);
+    }
+
+    /**
+     * Deregister parameters.
+     */
+    @After
+    public void deregisterParameters() {
+        ParameterService.deregister(ContextParameterConstants.DISTRIBUTOR_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.LOCKING_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.PERSISTENCE_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.SCHEMA_GROUP_NAME);
+    }
+
+    @Test
+    public void testAlbumInit() throws ContextException {
+        assertThatThrownBy(() -> new ApexInternalContext(null))
+            .hasMessage("internal context update failed, supplied model is null");
+        ApexInternalContext context = new ApexInternalContext(policyModel);
+
+        assertEquals(policyModel.getKey(), context.getKey());
+        assertEquals(1, context.getContextAlbums().size());
+
+        AxArtifactKey albumKey = new AxArtifactKey("Album:0.0.1");
+        assertEquals(album.getId(), context.get(albumKey).getKey().getId());
+        assertEquals(album.getId(), context.get(albumKey.getName()).getKey().getId());
+        assertEquals(album.getId(), context.get(albumKey.getName(), albumKey.getVersion()).getKey().getId());
+        assertEquals(album.getId(), context.getAll(albumKey.getName()).iterator().next().getKey().getId());
+        assertEquals(album.getId(),
+                        context.getAll(albumKey.getName(), albumKey.getVersion()).iterator().next().getKey().getId());
+
+        context.clear();
+        assertEquals(1, context.getContextAlbums().size());
+
+        assertEquals("ApexInternalContext [contextAlbums={AxArtifactKey:(name=Album,version=0.0.1)",
+                        context.toString().substring(0, 76));
+    }
+
+    @Test
+    public void testAlbumUpdate() throws ContextException {
+        ApexInternalContext context = new ApexInternalContext(policyModel);
+        assertThatThrownBy(() -> context.update(null, false))
+            .hasMessage("internal context update failed, supplied model is null");
+
+        assertEquals(policyModel.getKey().getId(), context.getKey().getId());
+        assertEquals(1, context.getContextAlbums().size());
+
+        assertThatThrownBy(() -> context.update(incompatiblePolicyModel, false)).hasMessage(
+            "internal context update failed on context album \"Album:0.0.1\" " + "in model \"PolicyModel:0.0.1\", "
+                + "schema \"Schema:0.0.1\" on existing context model does not equal "
+                + "schema \"IncompatibleSchema:0.0.1\" on incoming model");
+
+        assertEquals(policyModel.getKey().getId(), context.getKey().getId());
+
+        context.update(newVersionPolicyModel, false);
+        assertEquals(newVersionPolicyModel.getKey().getId(), context.getKey().getId());
+
+        context.update(newPolicyModel, true);
+        assertEquals(newPolicyModel.getKey().getId(), context.getKey().getId());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java
new file mode 100644
index 000000000..3b682acd6
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java
@@ -0,0 +1,521 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019-2021 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.engine.impl;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.awaitility.Awaitility.await;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import io.prometheus.client.CollectorRegistry;
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.concurrent.TimeUnit;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.parameters.ContextParameterConstants;
+import org.onap.policy.apex.context.parameters.DistributorParameters;
+import org.onap.policy.apex.context.parameters.LockManagerParameters;
+import org.onap.policy.apex.context.parameters.PersistorParameters;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+import org.onap.policy.apex.core.engine.EngineParameterConstants;
+import org.onap.policy.apex.core.engine.EngineParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.StateMachineExecutor;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+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.AxReferenceKey;
+import org.onap.policy.apex.model.basicmodel.service.ModelService;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
+import org.onap.policy.apex.model.enginemodel.concepts.AxEngineState;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvents;
+import org.onap.policy.apex.model.policymodel.concepts.AxPolicy;
+import org.onap.policy.apex.model.policymodel.concepts.AxPolicyModel;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the engine implementation.
+ */
+public class ApexEngineImplTest {
+    private static final String ENGINE_ID = "Engine:0.0.1";
+
+    private AxPolicyModel policyModel;
+    private AxPolicyModel incompatiblePolicyModel;
+    private AxPolicyModel policyModelWithStates;
+
+    @Mock
+    StateMachineHandler smHandlerMock;
+
+    /**
+     * Set up services.
+     */
+    @BeforeClass
+    public static void setup() {
+        ParameterService.register(new SchemaParameters());
+        ParameterService.register(new DistributorParameters());
+        ParameterService.register(new LockManagerParameters());
+        ParameterService.register(new PersistorParameters());
+        ParameterService.register(new EngineParameters());
+    }
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void initializeMocking() throws ApexException {
+        MockitoAnnotations.initMocks(this);
+
+        Mockito.doThrow(new StateMachineException("mocked state machine exception",
+                        new IOException("nexted exception"))).when(smHandlerMock).execute(Mockito.anyObject());
+    }
+
+    /**
+     * Create policy models.
+     */
+    @Before
+    public void createPolicyModels() {
+        AxArtifactKey modelKey = new AxArtifactKey("PolicyModel:0.0.1");
+        policyModel = new AxPolicyModel(modelKey);
+
+        AxArtifactKey schemaKey = new AxArtifactKey("Schema:0.0.1");
+        AxContextSchema schema = new AxContextSchema(schemaKey, "Java", "java.lang.String");
+        policyModel.getSchemas().getSchemasMap().put(schemaKey, schema);
+
+        AxArtifactKey albumKey = new AxArtifactKey("Album:0.0.1");
+        AxContextAlbum album = new AxContextAlbum(albumKey, "Policy", true, schemaKey);
+
+        policyModel.getAlbums().getAlbumsMap().put(albumKey, album);
+
+        AxEvents events = new AxEvents();
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        AxEvent event = new AxEvent(eventKey, "event.name.space", "source", "target");
+        events.getEventMap().put(eventKey, event);
+        policyModel.setEvents(events);
+
+        AxArtifactKey incompatibleModelKey = new AxArtifactKey("IncompatiblePolicyModel:0.0.2");
+        incompatiblePolicyModel = new AxPolicyModel(incompatibleModelKey);
+
+        AxArtifactKey incompatibleSchemaKey = new AxArtifactKey("IncompatibleSchema:0.0.1");
+        AxContextSchema incompatibleSchema = new AxContextSchema(incompatibleSchemaKey, "Java", "java.lang.Integer");
+        incompatiblePolicyModel.getSchemas().getSchemasMap().put(incompatibleSchemaKey, incompatibleSchema);
+
+        AxContextAlbum incompatibleAlbum = new AxContextAlbum(albumKey, "Policy", true, incompatibleSchemaKey);
+        incompatiblePolicyModel.getAlbums().getAlbumsMap().put(albumKey, incompatibleAlbum);
+
+        AxArtifactKey modelKeyStates = new AxArtifactKey("PolicyModelStates:0.0.1");
+        policyModelWithStates = new AxPolicyModel(modelKeyStates);
+        policyModelWithStates.getSchemas().getSchemasMap().put(schemaKey, schema);
+        policyModelWithStates.getAlbums().getAlbumsMap().put(albumKey, album);
+        policyModelWithStates.setEvents(events);
+
+        AxPolicy policy0 = new AxPolicy(new AxArtifactKey("Policy0:0.0.1"));
+        AxState state0 = new AxState(new AxReferenceKey(policy0.getKey(), "state0"));
+        state0.setTrigger(eventKey);
+        policy0.getStateMap().put(state0.getKey().getLocalName(), state0);
+        policy0.setFirstState(state0.getKey().getLocalName());
+
+        policyModelWithStates.getPolicies().getPolicyMap().put(policy0.getKey(), policy0);
+
+        AxPolicy policy1 = new AxPolicy(new AxArtifactKey("Policy1:0.0.1"));
+        AxState state1 = new AxState(new AxReferenceKey(policy1.getKey(), "state1"));
+        state1.setTrigger(eventKey);
+        policy1.getStateMap().put(state1.getKey().getLocalName(), state1);
+        policy1.setFirstState(state1.getKey().getLocalName());
+
+        policyModelWithStates.getPolicies().getPolicyMap().put(policy1.getKey(), policy1);
+    }
+
+    /**
+     * Clear registrations.
+     */
+    @AfterClass
+    public static void teardown() {
+        ParameterService.deregister(ContextParameterConstants.SCHEMA_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.DISTRIBUTOR_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.LOCKING_GROUP_NAME);
+        ParameterService.deregister(ContextParameterConstants.PERSISTENCE_GROUP_NAME);
+        ParameterService.deregister(EngineParameterConstants.MAIN_GROUP_NAME);
+    }
+
+    @Test
+    public void testSanity() throws ApexException  {
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+        assertNotNull(engine);
+        assertEquals(engineKey, engine.getKey());
+
+        assertThatThrownBy(engine::start).hasMessage("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
+                            + "engine has not been initialized, its model is not loaded");
+
+        assertThatThrownBy(engine::stop)
+            .hasMessage("stop()<-Engine:0.0.1,STOPPED, cannot stop engine, " + "engine is already stopped");
+
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+        assertEquals(0, engine.getEngineContext().size());
+        assertEquals(engineKey, engine.getEngineStatus().getKey());
+        assertNull(engine.getInternalContext());
+
+        engine.clear();
+
+        assertThatThrownBy(() -> engine.addEventListener(null, null))
+            .hasMessage("addEventListener()<-Engine:0.0.1,STOPPED, listenerName is null");
+
+        assertThatThrownBy(() -> engine.addEventListener("myListener", null))
+            .hasMessage("addEventListener()<-Engine:0.0.1,STOPPED, listener is null");
+
+        assertThatThrownBy(() -> engine.removeEventListener(null))
+            .hasMessage("removeEventListener()<-Engine:0.0.1,STOPPED, listenerName is null");
+    }
+
+    @Test
+    public void testListener() throws ApexException {
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+
+        engine.addEventListener("myListener", new DummyListener());
+        engine.removeEventListener("myListener");
+
+        assertNull(engine.createEvent(null));
+
+        assertFalse(engine.handleEvent(null));
+
+        assertThatThrownBy(() -> engine.updateModel(null, false))
+            .hasMessage("updateModel()<-Engine:0.0.1, Apex model is not defined, it has a null value");
+
+        engine.updateModel(policyModel, false);
+
+        // Force a context exception
+        ModelService.registerModel(AxPolicyModel.class, new AxPolicyModel());
+        assertThatThrownBy(() -> engine.updateModel(incompatiblePolicyModel, false))
+            .hasMessage("updateModel()<-Engine:0.0.1, error setting the context for engine \"Engine:0.0.1\"");
+
+        engine.updateModel(policyModel, false);
+
+        assertNotNull(engine.getInternalContext());
+        assertEquals(1, engine.getEngineContext().size());
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertThatThrownBy(engine::start)
+            .hasMessage("start()<-Engine:0.0.1,READY, cannot start engine, engine not in state STOPPED");
+
+        assertThatThrownBy(engine::clear)
+            .hasMessage("clear()<-Engine:0.0.1,READY, cannot clear engine, engine is not stopped");
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.clear();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        assertThatThrownBy(engine::start).hasMessage("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
+            + "engine has not been initialized, its model is not loaded");
+
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertNull(engine.createEvent(null));
+    }
+
+    @Test
+    public void testEventKey() throws ApexException {
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+        engine.updateModel(policyModel, false);
+        engine.start();
+
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        EnEvent event = engine.createEvent(eventKey);
+        assertEquals(eventKey, event.getKey());
+
+        assertTrue(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.addEventListener("myListener", new DummyListener());
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertThatThrownBy(() -> engine.updateModel(policyModel, false)).hasMessage(
+            "updateModel()<-Engine:0.0.1, cannot update model, engine should be stopped but is in state READY");
+
+        assertTrue(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.addEventListener("badListener", new DummyEnEventListener());
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertFalse(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.removeEventListener("badListener");
+        engine.addEventListener("slowListener", new DummySlowEnEventListener());
+    }
+
+    @Test
+    public void testState() throws InterruptedException, ApexException {
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+        assertNotNull(engine);
+        assertEquals(engineKey, engine.getKey());
+
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        DummySlowEnEventListener slowListener = new DummySlowEnEventListener();
+        engine.addEventListener("slowListener", slowListener);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        EnEvent event = engine.createEvent(eventKey);
+        assertEquals(eventKey, event.getKey());
+
+        // 1 second is less than the 3 second wait on engine stopping
+        slowListener.setWaitTime(1000);
+        (new Thread() {
+            @Override
+            public void run() {
+                engine.handleEvent(event);
+            }
+        }).start();
+        await().atLeast(50, TimeUnit.MILLISECONDS).until(() -> engine.getState().equals(AxEngineState.EXECUTING));
+        assertEquals(AxEngineState.EXECUTING, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.EXECUTING);
+
+        assertFalse(engine.handleEvent(event));
+        assertNotNull(engine.createEvent(eventKey));
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        // 4 seconds is more than the 3 second wait on engine stopping
+        slowListener.setWaitTime(4000);
+        (new Thread() {
+            @Override
+            public void run() {
+                engine.handleEvent(event);
+            }
+        }).start();
+
+        await().atLeast(50, TimeUnit.MILLISECONDS).until(() -> engine.getState().equals(AxEngineState.EXECUTING));
+        assertEquals(AxEngineState.EXECUTING, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.EXECUTING);
+        assertThatThrownBy(engine::stop)
+            .hasMessage("stop()<-Engine:0.0.1,STOPPED, error stopping engine, engine stop timed out");
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+        engine.clear();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+    }
+
+    @Test
+    public void testStateMachineError() throws InterruptedException, IllegalArgumentException, IllegalAccessException,
+                    NoSuchFieldException, SecurityException, ApexException {
+
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+        assertNotNull(engine);
+        assertEquals(engineKey, engine.getKey());
+
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        final Field smHandlerField = engine.getClass().getDeclaredField("stateMachineHandler");
+        smHandlerField.setAccessible(true);
+        smHandlerField.set(engine, smHandlerMock);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        EnEvent event = engine.createEvent(eventKey);
+        assertEquals(eventKey, event.getKey());
+
+        assertFalse(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+        Mockito.doThrow(new StateMachineException("mocked state machine exception",
+                new IOException("nexted exception"))).when(smHandlerMock).start();
+        assertThatThrownBy(engine::start).hasMessage("updateModel()<-Engine:0.0.1, error starting the engine state "
+                + "machines \"Engine:0.0.1\"");
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.clear();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+    }
+
+    @Test
+    public void testStateMachineHandler() throws InterruptedException, IllegalArgumentException, IllegalAccessException,
+                    NoSuchFieldException, SecurityException, ApexException {
+        AxArtifactKey engineKey = new AxArtifactKey(ENGINE_ID);
+        ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
+        assertNotNull(engine);
+        assertEquals(engineKey, engine.getKey());
+
+        engine.updateModel(policyModelWithStates, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        EnEvent event = engine.createEvent(eventKey);
+        assertEquals(eventKey, event.getKey());
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        // Can't work, state is not fully defined
+        assertFalse(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        final Field smHandlerField = engine.getClass().getDeclaredField("stateMachineHandler");
+        smHandlerField.setAccessible(true);
+        StateMachineHandler smHandler = (StateMachineHandler) smHandlerField.get(engine);
+
+        final Field smExecutorMapField = smHandler.getClass().getDeclaredField("stateMachineExecutorMap");
+        smExecutorMapField.setAccessible(true);
+        @SuppressWarnings("unchecked")
+        HashMap<AxEvent, StateMachineExecutor> smExMap = (HashMap<AxEvent, StateMachineExecutor>) smExecutorMapField
+                        .get(smHandler);
+
+        assertEquals(1, smExMap.size());
+        DummySmExecutor dummyExecutor = new DummySmExecutor(null, event.getKey());
+        smExMap.put(event.getAxEvent(), dummyExecutor);
+        ApexInternalContext internalContext = new ApexInternalContext(policyModelWithStates);
+        assertThatThrownBy(() -> dummyExecutor.setContext(null, null, internalContext))
+            .isInstanceOf(NullPointerException.class);
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        assertThatThrownBy(engine::start).hasMessageContaining("updateModel()<-Engine:0.0.1, error starting the "
+                    + "engine state machines \"Engine:0.0.1\"");
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        // Works, Dummy executor fakes event execution
+        assertTrue(engine.handleEvent(event));
+        assertEquals(AxEngineState.READY, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.READY);
+
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+
+        engine.clear();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+        checkAxEngineStateMetric(AxEngineState.STOPPED);
+    }
+
+    private void checkAxEngineStateMetric(AxEngineState state) {
+        Double stateMetric = CollectorRegistry.defaultRegistry
+            .getSampleValue("pdpa_engine_state", new String[]{"engine_instance_id"}, new String[]{ENGINE_ID});
+        assertEquals(stateMetric.intValue(), state.getStateIdentifier());
+    }
+}
\ No newline at end of file
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyEnEventListener.java b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyEnEventListener.java
new file mode 100644
index 000000000..b429295ad
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyEnEventListener.java
@@ -0,0 +1,40 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.engine.impl;
+
+import org.onap.policy.apex.core.engine.engine.EnEventListener;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
+
+/**
+ * Dummy engine event listener for unit test.
+ *
+ */
+public class DummyEnEventListener implements EnEventListener {
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void onEnEvent(EnEvent enEvent) throws ApexException {
+        throw new ApexException("not implemented on dummy class");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyListener.java b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyListener.java
new file mode 100644
index 000000000..6256ff498
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummyListener.java
@@ -0,0 +1,40 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.engine.impl;
+
+import org.onap.policy.apex.core.engine.engine.EnEventListener;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
+
+/**
+ * Dummy engine event listener for unit test.
+ *
+ */
+public class DummyListener implements EnEventListener {
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void onEnEvent(EnEvent enEvent) throws ApexException {
+        // Do nothing
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySlowEnEventListener.java b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySlowEnEventListener.java
new file mode 100644
index 000000000..e794a7d04
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySlowEnEventListener.java
@@ -0,0 +1,56 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019-2021 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.core.engine.engine.impl;
+
+import org.onap.policy.apex.core.engine.engine.EnEventListener;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
+
+/**
+ * Dummy engine event listener for unit test.
+ * Thread.sleep is used to simulate a slow event listener.
+ *
+ */
+public class DummySlowEnEventListener implements EnEventListener {
+
+    private long waitTime;
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void onEnEvent(EnEvent enEvent) throws ApexException {
+        try {
+            Thread.sleep(waitTime);
+        } catch (InterruptedException ie) {
+            //Do nothing
+        }
+    }
+
+    public long getWaitTime() {
+        return waitTime;
+    }
+
+    public void setWaitTime(long waitTime) {
+        this.waitTime = waitTime;
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySmExecutor.java b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySmExecutor.java
new file mode 100644
index 000000000..df4d9279e
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/engine/impl/DummySmExecutor.java
@@ -0,0 +1,85 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.engine.impl;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.ExecutorFactory;
+import org.onap.policy.apex.core.engine.executor.StateMachineExecutor;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+
+/**
+ * Dummy state machine executor for testing.
+ */
+public class DummySmExecutor extends StateMachineExecutor {
+    private boolean cleanupWorks = false;
+    private boolean prepareWorks;
+
+    /**
+     * Constructor.
+     *
+     * @param executorFactory the factory for executors
+     * @param owner the owner key
+     */
+    public DummySmExecutor(ExecutorFactory executorFactory, AxArtifactKey owner) {
+        super(executorFactory, owner);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void prepare() throws StateMachineException {
+        if (prepareWorks) {
+            prepareWorks = false;
+        } else {
+            prepareWorks = true;
+            throw new StateMachineException("dummy state machine executor exception");
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Collection<EnEvent> execute(final long executionId, final Properties executionProperties,
+        final EnEvent incomingEvent) {
+        return List.of(incomingEvent);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void cleanUp() throws StateMachineException {
+        if (cleanupWorks) {
+            cleanupWorks = false;
+        } else {
+            cleanupWorks = true;
+            throw new StateMachineException("dummy state machine executor exception");
+        }
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/event/DummyAxKey.java b/core/src/test/java/org/onap/policy/apex/core/engine/event/DummyAxKey.java
new file mode 100644
index 000000000..eafa7f419
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/event/DummyAxKey.java
@@ -0,0 +1,131 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.event;
+
+import java.util.List;
+import org.apache.commons.lang3.NotImplementedException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
+import org.onap.policy.apex.model.basicmodel.concepts.AxKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
+
+/**
+ * Dummy Key Class.
+ */
+public class DummyAxKey extends AxKey {
+    private static final long serialVersionUID = 964899169013353800L;
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public int compareTo(AxConcept concept) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String getId() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Compatibility getCompatibility(AxKey otherKey) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean isCompatible(AxKey otherKey) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxKey getKey() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public List<AxKey> getKeys() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxValidationResult validate(AxValidationResult result) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void clean() {
+        throw new NotImplementedException("Not implemented on dummy class");
+
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean equals(Object otherObject) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "Dummy Key";
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public int hashCode() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxConcept copyTo(AxConcept target) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/event/EnEventTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnEventTest.java
new file mode 100644
index 000000000..49b4f80d2
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnEventTest.java
@@ -0,0 +1,170 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020-2021 Nordix Foundation
+ *  Modifications Copyright (C) 2022 Bell Canada. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.event;
+
+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.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onap.policy.apex.context.parameters.ContextParameterConstants;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.basicmodel.service.ModelService;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvents;
+import org.onap.policy.apex.model.eventmodel.concepts.AxField;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the engine event class.
+ */
+public class EnEventTest {
+    /**
+     * Set up the services.
+     */
+    @Before
+    public void setupServices() {
+        ModelService.registerModel(AxContextSchemas.class, new AxContextSchemas());
+        ModelService.registerModel(AxEvents.class, new AxEvents());
+        ParameterService.register(new SchemaParameters());
+    }
+
+    /**
+     * Tear down the services.
+     */
+    @After
+    public void teardownServices() {
+        ModelService.deregisterModel(AxContextSchema.class);
+        ModelService.deregisterModel(AxEvents.class);
+        ParameterService.deregister(ContextParameterConstants.SCHEMA_GROUP_NAME);
+    }
+
+    @Test
+    public void testEnEvent() {
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        assertThatThrownBy(() -> new EnEvent(eventKey))
+            .hasMessage("event definition is null or was not found in model service");
+        assertThatThrownBy(() -> new EnEvent((AxEvent) null))
+            .hasMessage("event definition is null or was not found in model service");
+        AxEvent axEvent = new AxEvent(eventKey, "a.name.space", "some source", "some target");
+        ModelService.getModel(AxEvents.class).getEventMap().put(eventKey, axEvent);
+
+        EnEvent event = new EnEvent(eventKey);
+        assertEquals(eventKey, event.getKey());
+        assertEquals("Event:0.0.1", event.getId());
+        assertEquals("Event", event.getName());
+        assertEquals(axEvent, event.getAxEvent());
+        event.setExecutionId(123454321L);
+        assertEquals(123454321L, event.getExecutionId());
+        event.setExceptionMessage("Something happened");
+        assertEquals("Something happened", event.getExceptionMessage());
+        AxConcept[] usedArtifactStackArray =
+            { eventKey };
+        event.setUserArtifactStack(usedArtifactStackArray);
+        assertEquals(usedArtifactStackArray.length, event.getUserArtifactStack().length);
+        assertEquals("EnEvent [axEvent=AxEvent:(key=AxArtifactKey:(name=Event,version=0.0.1),nameSpace=a.name.space,"
+                        + "source=some source,target=some target,parameter={},toscaPolicyState=), "
+                        + "userArtifactStack=[AxArtifactKey:(name=Event,version=0.0.1)], map={}]", event.toString());
+        assertThatThrownBy(() -> event.put(null, null))
+            .hasMessage("null keys are illegal on method parameter \"key\"");
+        assertThatThrownBy(() -> event.put("NonField", null))
+            .hasMessage("parameter with key \"NonField\" not defined on event \"Event\"");
+    }
+
+    @Test
+    public void testAxEvent() {
+        AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
+        AxEvent axEvent = new AxEvent(eventKey, "a.name.space", "some source", "some target");
+        ModelService.getModel(AxEvents.class).getEventMap().put(eventKey, axEvent);
+        EnEvent event = new EnEvent(eventKey);
+
+        AxReferenceKey fieldKey = new AxReferenceKey("Parent", "0.0.1", "MyParent", "MyField");
+        AxArtifactKey fieldSchemaKey = new AxArtifactKey("FieldSchema:0.0.1");
+        AxField axField = new AxField(fieldKey, fieldSchemaKey);
+
+        AxConcept[] usedArtifactStackArrayMultiple =
+            { eventKey, fieldKey, new DummyAxKey() };
+        event.setUserArtifactStack(usedArtifactStackArrayMultiple);
+
+        AxContextSchema schema = new AxContextSchema(fieldSchemaKey, "Java", "java.lang.Integer");
+        ModelService.getModel(AxContextSchemas.class).getSchemasMap().put(fieldSchemaKey, schema);
+
+        Map<String, AxField> parameterMap = new LinkedHashMap<>();
+        parameterMap.put("MyField", axField);
+        ModelService.getModel(AxEvents.class).get(eventKey).setParameterMap(parameterMap);
+
+        event.put("MyField", null);
+        assertNull(event.get("MyField"));
+
+        assertThatThrownBy(() -> event.put("MyField", "Hello"))
+            .hasMessage("Parent:0.0.1:MyParent:MyField: object \"Hello\" of class \"java.lang.String\" "
+                            + "not compatible with class \"java.lang.Integer\"");
+        event.put("MyField", 123);
+        assertEquals(123, event.get("MyField"));
+
+        assertTrue(event.keySet().contains("MyField"));
+        assertTrue(event.values().contains(123));
+        assertEquals("MyField", event.entrySet().iterator().next().getKey());
+
+        event.putAll(event);
+
+        assertThatThrownBy(() -> event.get(null))
+            .hasMessage("null values are illegal on method parameter \"key\"");
+        assertThatThrownBy(() -> event.get("NonField"))
+            .hasMessage("parameter with key NonField not defined on this event");
+        assertThatThrownBy(() -> event.remove(null))
+            .hasMessage("null keys are illegal on method parameter \"key\"");
+        assertThatThrownBy(() -> event.remove("NonField"))
+            .hasMessage("parameter with key NonField not defined on this event");
+        event.remove("MyField");
+        assertNull(event.get("MyField"));
+
+        event.put("MyField", 123);
+        assertEquals(123, event.get("MyField"));
+        event.clear();
+        assertNull(event.get("MyField"));
+
+        assertNotEquals(0, event.hashCode());
+        // disabling sonar because this code tests the equals() method
+        assertEquals(event, event); // NOSONAR
+        assertNotNull(event);
+        Map<String, Object> hashMap = new HashMap<>();
+        assertNotEquals(event, hashMap);
+
+        EnEvent otherEvent = new EnEvent(eventKey);
+        assertEquals(event, otherEvent);
+    }
+}
\ No newline at end of file
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/event/EnExceptionTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnExceptionTest.java
new file mode 100644
index 000000000..5ca49e479
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnExceptionTest.java
@@ -0,0 +1,41 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.event;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import org.junit.Test;
+
+/**
+ * Test the event exception class.
+ */
+public class EnExceptionTest {
+
+    @Test
+    public void testEnException() {
+        EnException ene = new EnException("Message");
+        assertEquals("Message", ene.getMessage());
+
+        ene = new EnException("Message", new IOException());
+        assertEquals("Message", ene.getMessage());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/event/EnFieldTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnFieldTest.java
new file mode 100644
index 000000000..dbe2fa3c8
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/event/EnFieldTest.java
@@ -0,0 +1,93 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.event;
+
+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 org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onap.policy.apex.context.parameters.ContextParameterConstants;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+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.service.ModelService;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
+import org.onap.policy.apex.model.eventmodel.concepts.AxField;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the EnField class.
+ */
+public class EnFieldTest {
+    /**
+     * Set up the services.
+     */
+    @Before
+    public void setupServices() {
+        AxContextSchemas schemas = new AxContextSchemas();
+        ModelService.registerModel(AxContextSchemas.class, schemas);
+        ParameterService.register(new SchemaParameters());
+    }
+
+    /**
+     * Tear down the services.
+     */
+    @After
+    public void teardownServices() {
+        ModelService.deregisterModel(AxContextSchemas.class);
+        ParameterService.deregister(ContextParameterConstants.SCHEMA_GROUP_NAME);
+    }
+
+    @Test
+    public void testEnField() {
+        AxReferenceKey fieldKey = new AxReferenceKey("Parent", "0.0.1", "MyParent", "MyField");
+        AxArtifactKey fieldSchemaKey = new AxArtifactKey("FieldSchema:0.0.1");
+        AxField axField = new AxField(fieldKey, fieldSchemaKey);
+
+        assertThatThrownBy(() -> new EnField(axField, null))
+            .hasMessage("schema helper cannot be created for parameter with key \"Parent:0.0.1:MyParent:My"
+                + "Field\" with schema \"AxArtifactKey:(name=FieldSchema,version=0.0.1)\"");
+        AxContextSchema schema = new AxContextSchema(fieldSchemaKey, "Java", "java.lang.Integer");
+        ModelService.getModel(AxContextSchemas.class).getSchemasMap().put(fieldSchemaKey, schema);
+        EnField field = new EnField(axField, 123);
+
+        assertEquals(axField, field.getAxField());
+        assertEquals(123, field.getValue());
+        assertEquals(fieldKey, field.getKey());
+        assertEquals("MyField", field.getName());
+        assertEquals("org.onap.policy.apex.context.impl.schema.java.JavaSchemaHelper",
+            field.getSchemaHelper().getClass().getName());
+        assertEquals(123, field.getAssignableValue());
+        assertEquals("EnField [axField=AxField:(key=AxReferenceKey:(parentKeyName=Parent,parentKeyVersion=0.0.1,"
+            + "parentLocalName=MyParent,localName=MyField),fieldSchemaKey=AxArtifactKey:"
+            + "(name=FieldSchema,version=0.0.1),optional=false), value=123]", field.toString());
+        assertTrue(field.isAssignableValue());
+
+        field = new EnField(axField, "Hello");
+        assertFalse(field.isAssignableValue());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyFailingTaskExecutor.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyFailingTaskExecutor.java
new file mode 100644
index 000000000..4d4fb639f
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyFailingTaskExecutor.java
@@ -0,0 +1,30 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+/**
+ * Dummy task executor for testing.
+ */
+public class DummyFailingTaskExecutor extends TaskExecutor {
+    public DummyFailingTaskExecutor() throws InstantiationException {
+        throw new InstantiationException("I always fail");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyStateFinalizerExecutor.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyStateFinalizerExecutor.java
new file mode 100644
index 000000000..e4e3ddf0d
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyStateFinalizerExecutor.java
@@ -0,0 +1,65 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+import java.util.Map;
+import java.util.Properties;
+import lombok.NoArgsConstructor;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+
+/**
+ * Dummy state finalizer executor for testing.
+ */
+@NoArgsConstructor
+public class DummyStateFinalizerExecutor extends StateFinalizerExecutor {
+    private boolean override;
+
+    private boolean returnBad;
+
+    public DummyStateFinalizerExecutor(final boolean override) {
+        this.override = override;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String execute(final long executionId, final Properties executionProperties,
+            final Map<String, Object> newIncomingFields) throws StateMachineException, ContextException {
+
+        if (!override) {
+            super.execute(executionId, executionProperties, newIncomingFields);
+        }
+
+        if (returnBad) {
+            return "stateOutputBad";
+        } else {
+            return "stateOutput1";
+        }
+    }
+
+    public void setReturnBad(boolean returnBad) {
+        this.returnBad = returnBad;
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskExecutor.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskExecutor.java
new file mode 100644
index 000000000..8172eefcc
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskExecutor.java
@@ -0,0 +1,91 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019-2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+import java.util.Map;
+import java.util.Properties;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+
+/**
+ * Dummy task executor for testing.
+ */
+@NoArgsConstructor
+@AllArgsConstructor
+public class DummyTaskExecutor extends TaskExecutor {
+    private static final String EVENT_KEY = "Event1:0.0.1";
+    private boolean override;
+
+    @Override
+    public void prepare() throws StateMachineException {
+        if (!override) {
+            super.prepare();
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public  Map<String, Map<String, Object>> execute(final long executionId, final Properties executionProperties,
+            final Map<String, Object> newIncomingFields) throws StateMachineException, ContextException {
+        if (!override) {
+            super.execute(executionId, executionProperties, newIncomingFields);
+        }
+
+        AxArtifactKey eventKey = new AxArtifactKey(EVENT_KEY);
+        return Map.of(eventKey.getName(), new EnEvent(eventKey));
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxTask getSubject() {
+        if (!override) {
+            return super.getSubject();
+        }
+
+        AxArtifactKey taskKey = new AxArtifactKey("FirstTask:0.0.1");
+        AxTask task = new AxTask(taskKey);
+        task.setOutputEvents(Map.of("Event1", new AxEvent(new AxArtifactKey(EVENT_KEY))));
+        return task;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void cleanUp() throws StateMachineException {
+        if (!override) {
+            super.cleanUp();
+        }
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskSelectExecutor.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskSelectExecutor.java
new file mode 100644
index 000000000..a5525ac83
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/DummyTaskSelectExecutor.java
@@ -0,0 +1,74 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+import java.util.Properties;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+
+/**
+ * Dummy task selection executor for testing.
+ */
+@NoArgsConstructor
+@AllArgsConstructor
+public class DummyTaskSelectExecutor extends TaskSelectExecutor {
+    private boolean override;
+
+    @Setter
+    private static int taskNo;
+
+    @Override
+    public void prepare() throws StateMachineException {
+        if (!override) {
+            super.prepare();
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxArtifactKey execute(final long executionId, final Properties executionProperties,
+            final EnEvent newIncomingEvent) throws StateMachineException, ContextException {
+        if (!override) {
+            return super.execute(executionId, executionProperties, newIncomingEvent);
+        }
+
+        return new AxArtifactKey("task" + (taskNo++) + ":0.0.1");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void cleanUp() throws StateMachineException {
+        if (!override) {
+            super.cleanUp();
+        }
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateExecutorTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateExecutorTest.java
new file mode 100644
index 000000000..f3e12cc1f
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateExecutorTest.java
@@ -0,0 +1,88 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+
+/**
+ * Test task executor.
+ */
+public class StateExecutorTest {
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private AxState axStateMock;
+
+    @Mock
+    private ExecutorFactory executorFactoryMock;
+
+    @Mock
+    private Executor<EnEvent, StateOutput, AxState, ApexInternalContext> nextExecutorMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        Mockito.doReturn(new AxReferenceKey("Policy:0.0.1:PolName:State0")).when(axStateMock).getKey();
+    }
+
+    @Test
+    public void testStateExecutor() {
+        StateExecutor executor = new StateExecutor(executorFactoryMock);
+
+        executor.setContext(null, axStateMock, internalContextMock);
+        assertEquals("Policy:0.0.1:PolName:State0", executor.getKey().getId());
+        assertEquals(null, executor.getParent());
+        assertEquals(internalContextMock, executor.getContext());
+        assertEquals(null, executor.getNext());
+        assertEquals(null, executor.getIncoming());
+        assertEquals(null, executor.getOutgoing());
+        assertEquals(axStateMock, executor.getSubject());
+
+        executor.setParameters(new ExecutorParameters());
+        executor.setNext(nextExecutorMock);
+        assertEquals(nextExecutorMock, executor.getNext());
+        executor.setNext(null);
+        assertEquals(null, executor.getNext());
+
+        assertThatThrownBy(() -> executor.executePre(0, null, null))
+            .hasMessage("execution pre work not implemented on class");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessage("execution post work not implemented on class");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateFinalizerExecutorTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateFinalizerExecutorTest.java
new file mode 100644
index 000000000..8f6544497
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateFinalizerExecutorTest.java
@@ -0,0 +1,139 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+
+import java.util.Map;
+import java.util.Properties;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateFinalizerLogic;
+
+/**
+ * Test task executor.
+ */
+public class StateFinalizerExecutorTest {
+    @Mock
+    private Executor<?, ?, ?, ?> parentMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private AxStateFinalizerLogic stateFinalizerLogicMock;
+
+    @Mock
+    private Executor<Map<String, Object>, String, AxStateFinalizerLogic, ApexInternalContext> nextExecutorMock;
+
+    @Mock
+    private EnEvent incomingEvent;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        AxState state = new AxState();
+        state.getStateOutputs().put("ValidOutput", null);
+
+        Mockito.doReturn(state).when(parentMock).getSubject();
+
+        Mockito.doReturn(new AxReferenceKey("State:0.0.1:StateName:StateSFL")).when(stateFinalizerLogicMock).getKey();
+    }
+
+    @Test
+    public void testStateFinalizerExecutor() throws StateMachineException, ContextException {
+        DummyStateFinalizerExecutor executor = new DummyStateFinalizerExecutor();
+
+        executor.setContext(parentMock, stateFinalizerLogicMock, internalContextMock);
+        assertEquals("State:0.0.1:StateName:StateSFL", executor.getKey().getId());
+        assertEquals(null, executor.getExecutionContext());
+        assertEquals(parentMock, executor.getParent());
+        assertEquals(internalContextMock, executor.getContext());
+        assertEquals(null, executor.getNext());
+        assertEquals(null, executor.getIncoming());
+        assertEquals(null, executor.getOutgoing());
+        assertEquals(stateFinalizerLogicMock, executor.getSubject());
+
+        executor.setParameters(new ExecutorParameters());
+        executor.setNext(nextExecutorMock);
+        assertEquals(nextExecutorMock, executor.getNext());
+        executor.setNext(null);
+        assertEquals(null, executor.getNext());
+
+        assertThatThrownBy(executor::cleanUp)
+            .hasMessage("cleanUp() not implemented on class");
+        Mockito.doReturn(null).when(stateFinalizerLogicMock).getLogic();
+
+        assertThatThrownBy(executor::prepare)
+            .hasMessage("state finalizer logic cannot be null.");
+        Mockito.doReturn("some task logic").when(stateFinalizerLogicMock).getLogic();
+
+        executor.prepare();
+
+        executor.executePre(0, new Properties(), incomingEvent);
+        assertThatThrownBy(() -> executor.executePre(0, null, incomingEvent))
+            .hasMessageMatching("^executionProperties is marked .*on.*ull but is null$");
+
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        assertThatThrownBy(() -> executor.execute(0, new Properties(), incomingEvent))
+            .hasMessage("execute() not implemented on abstract StateFinalizerExecutionContext class, "
+                + "only on its subclasses");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessage("execute-post: state finalizer logic execution failure on state \"NULL:0.0.0:"
+                + "NULL:NULL\" on finalizer logic null");
+        executor.getExecutionContext().setMessage("Execution message");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessage("execute-post: state finalizer logic execution failure on state \"NULL:0.0.0:"
+                + "NULL:NULL\" on finalizer logic null, user message: Execution message");
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        assertThatThrownBy(() -> executor.executePost(true))
+            .hasMessage("execute-post: state finalizer logic \"null\" did not select an output state");
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        executor.getExecutionContext().setSelectedStateOutputName("ThisOutputDoesNotExist");
+        assertThatThrownBy(() -> executor.executePost(true))
+            .hasMessage("execute-post: state finalizer logic \"null\" selected output state "
+                    + "\"ThisOutputDoesNotExist\" that does not exsist on state \"NULL:0.0.0:NULL:NULL\"");
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        executor.getExecutionContext().setSelectedStateOutputName("ValidOutput");
+        executor.executePost(true);
+
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateMachineExecutorTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateMachineExecutorTest.java
new file mode 100644
index 000000000..5d91bd2b3
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/StateMachineExecutorTest.java
@@ -0,0 +1,336 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+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.Assert.assertTrue;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+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.service.ModelService;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvents;
+import org.onap.policy.apex.model.eventmodel.concepts.AxField;
+import org.onap.policy.apex.model.policymodel.concepts.AxPolicy;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateFinalizerLogic;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateOutput;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateTaskOutputType;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateTaskReference;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.apex.model.policymodel.concepts.AxTasks;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test task executor.
+ */
+public class StateMachineExecutorTest {
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private Executor<EnEvent, Collection<EnEvent>, AxPolicy, ApexInternalContext> nextExecutorMock;
+
+    @Mock
+    private ExecutorFactory executorFactoryMock;
+
+    @Mock
+    private EnEvent incomingEventMock;
+
+    private AxPolicy axPolicy = new AxPolicy();
+
+    private DummyTaskSelectExecutor dummyTsle;
+
+    private DummyStateFinalizerExecutor dummySfle;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        axPolicy.setKey(new AxArtifactKey("Policy:0.0.1"));
+
+        AxReferenceKey state0Key = new AxReferenceKey(axPolicy.getKey(), "state0");
+        AxState state0 = new AxState(state0Key);
+
+        AxReferenceKey state1Key = new AxReferenceKey(axPolicy.getKey(), "state1");
+        AxState state1 = new AxState(state1Key);
+
+        axPolicy.getStateMap().put("State0", state0);
+        axPolicy.getStateMap().put("State1", state1);
+        axPolicy.setFirstState("state0");
+
+        AxArtifactKey event0Key = new AxArtifactKey("Event0:0.0.1");
+        AxEvent event0 = new AxEvent(event0Key, "a.name.space", "source", "target");
+        AxArtifactKey event1Key = new AxArtifactKey("Event1:0.0.1");
+        AxEvent event1 = new AxEvent(event1Key, "a.name.space", "source", "target");
+        AxArtifactKey event2Key = new AxArtifactKey("Event2:0.0.1");
+        AxEvent event2 = new AxEvent(event2Key, "a.name.space", "source", "target");
+        AxEvents events = new AxEvents();
+        events.getEventMap().put(event0Key, event0);
+        events.getEventMap().put(event1Key, event1);
+        events.getEventMap().put(event2Key, event2);
+        ModelService.registerModel(AxEvents.class, events);
+
+        AxReferenceKey fieldKey = new AxReferenceKey("Event1:0.0.1:event:Field0");
+        AxArtifactKey stringSchemaKey = new AxArtifactKey("StringSchema:0.0.1");
+        AxContextSchema stringSchema = new AxContextSchema(stringSchemaKey, "Java", "java.lang.String");
+        AxContextSchemas schemas = new AxContextSchemas();
+        schemas.getSchemasMap().put(stringSchemaKey, stringSchema);
+        ModelService.registerModel(AxContextSchemas.class, schemas);
+
+        AxField event1Field0Definition = new AxField(fieldKey, stringSchemaKey);
+        event1.getParameterMap().put("Event1Field0", event1Field0Definition);
+
+        event0.getParameterMap().put("Event1Field0", event1Field0Definition);
+        event0.getParameterMap().put("UnusedField", event1Field0Definition);
+
+        Mockito.doReturn(event0Key).when(incomingEventMock).getKey();
+        Mockito.doReturn(event0).when(incomingEventMock).getAxEvent();
+
+        state0.setTrigger(event0Key);
+        state1.setTrigger(event1Key);
+
+        AxArtifactKey task0Key = new AxArtifactKey("task0:0.0.1");
+        AxTask task0 = new AxTask(task0Key);
+
+        AxArtifactKey task1Key = new AxArtifactKey("task1:0.0.1");
+        AxTask task1 = new AxTask(task1Key);
+
+        AxTasks tasks = new AxTasks();
+        tasks.getTaskMap().put(task0Key, task0);
+        tasks.getTaskMap().put(task1Key, task1);
+        ModelService.registerModel(AxTasks.class, tasks);
+
+        ParameterService.register(new SchemaParameters());
+
+        AxReferenceKey stateOutput0Key = new AxReferenceKey("Policy:0.0.1:state0:stateOutput0");
+        AxStateOutput stateOutput0 = new AxStateOutput(stateOutput0Key, event1Key, state1.getKey());
+
+        state0.getStateOutputs().put(stateOutput0Key.getLocalName(), stateOutput0);
+
+        AxReferenceKey stateOutput1Key = new AxReferenceKey("Policy:0.0.1:state0:stateOutput1");
+        AxStateOutput stateOutput1 = new AxStateOutput(stateOutput1Key, event2Key, AxReferenceKey.getNullKey());
+
+        state1.getStateOutputs().put(stateOutput1Key.getLocalName(), stateOutput1);
+
+        AxReferenceKey str0Key = new AxReferenceKey("Policy:0.0.1:state0:str0");
+        AxStateTaskReference str0 = new AxStateTaskReference(str0Key, AxStateTaskOutputType.DIRECT, stateOutput0Key);
+        state0.getTaskReferences().put(task0Key, str0);
+
+        AxReferenceKey sflKey = new AxReferenceKey("Policy:0.0.1:state1:sfl");
+        AxStateFinalizerLogic sfl = new AxStateFinalizerLogic(sflKey, "Java", "State fianlizer logic");
+        state1.getStateFinalizerLogicMap().put("sfl", sfl);
+
+        AxReferenceKey str1Key = new AxReferenceKey("Policy:0.0.1:state1:str1");
+        AxStateTaskReference str1 = new AxStateTaskReference(str1Key, AxStateTaskOutputType.LOGIC, sflKey);
+        state1.getTaskReferences().put(task1Key, str1);
+
+        Mockito.doReturn(new DummyTaskExecutor(true)).when(executorFactoryMock).getTaskExecutor(Mockito.anyObject(),
+            Mockito.anyObject(), Mockito.anyObject());
+
+        dummyTsle = new DummyTaskSelectExecutor(true);
+        Mockito.doReturn(dummyTsle).when(executorFactoryMock).getTaskSelectionExecutor(Mockito.anyObject(),
+            Mockito.anyObject(), Mockito.anyObject());
+
+        dummySfle = new DummyStateFinalizerExecutor(true);
+        Mockito.doReturn(dummySfle).when(executorFactoryMock).getStateFinalizerExecutor(Mockito.anyObject(),
+            Mockito.anyObject(), Mockito.anyObject());
+    }
+
+    @After
+    public void cleardown() {
+        ParameterService.clear();
+        ModelService.clear();
+    }
+
+    @Test
+    public void testStateMachineExecutor() throws StateMachineException, ContextException {
+        StateMachineExecutor executor =
+            new StateMachineExecutor(executorFactoryMock, new AxArtifactKey("OwnerKey:0.0.1"));
+
+        assertThatThrownBy(() -> executor.execute(0, null, incomingEventMock))
+            .hasMessage("no states defined on state machine");
+        executor.setContext(null, axPolicy, internalContextMock);
+        assertEquals("Policy:0.0.1", executor.getKey().getId());
+        assertNull(executor.getParent());
+        assertEquals(internalContextMock, executor.getContext());
+        assertNull(executor.getNext());
+        assertNull(executor.getIncoming());
+        assertTrue(executor.getOutgoing().isEmpty());
+        assertEquals(axPolicy, executor.getSubject());
+
+        executor.setParameters(new ExecutorParameters());
+        executor.setNext(nextExecutorMock);
+        assertEquals(nextExecutorMock, executor.getNext());
+        executor.setNext(null);
+        assertNull(executor.getNext());
+
+        assertThatThrownBy(() -> executor.executePre(0, null, null))
+            .hasMessage("execution pre work not implemented on class");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessage("execution post work not implemented on class");
+        assertThatThrownBy(executor::prepare)
+            .isInstanceOf(NullPointerException.class);
+        axPolicy.setFirstState("BadState");
+        executor.setContext(null, axPolicy, internalContextMock);
+        assertThatThrownBy(() -> executor.execute(0, null, incomingEventMock))
+            .hasMessage("first state not defined on state machine");
+        axPolicy.setFirstState("state0");
+        executor.setContext(null, axPolicy, internalContextMock);
+        executor.execute(0, null, incomingEventMock);
+
+        DummyTaskSelectExecutor.setTaskNo(0);
+        executor.execute(0, null, incomingEventMock);
+
+        AxReferenceKey badStateKey = new AxReferenceKey("Policy:0.0.1:PName:BadState");
+        axPolicy.getStateMap().get("State1").getStateOutputs().get("stateOutput1").setNextState(badStateKey);
+        DummyTaskSelectExecutor.setTaskNo(0);
+        assertThatThrownBy(() -> executor.execute(0, null, incomingEventMock))
+            .hasMessage("state execution failed, next state \"Policy:0.0.1:PName:BadState\" not found");
+        axPolicy.getStateMap().get("State1").getStateOutputs().get("stateOutput1")
+            .setNextState(AxReferenceKey.getNullKey());
+        DummyTaskSelectExecutor.setTaskNo(0);
+        executor.execute(0, null, incomingEventMock);
+
+        axPolicy.getStateMap().get("State1").setTrigger(new AxArtifactKey("BadTrigger:0.0.1"));
+        DummyTaskSelectExecutor.setTaskNo(0);
+        assertThatThrownBy(() -> executor.execute(0, null, incomingEventMock))
+            .hasMessage("incoming event \"Event1:0.0.1\" does not match trigger \"BadTrigger:0.0.1\" "
+                + "of state \"Policy:0.0.1:NULL:state1\"");
+        axPolicy.getStateMap().get("State1").setTrigger(new AxArtifactKey("Event1:0.0.1"));
+        DummyTaskSelectExecutor.setTaskNo(0);
+        executor.execute(0, null, incomingEventMock);
+
+        AxStateFinalizerLogic savedSfl = axPolicy.getStateMap().get("State1").getStateFinalizerLogicMap().get("sfl");
+        axPolicy.getStateMap().get("State1").getStateFinalizerLogicMap().put("sfl", null);
+        assertThatThrownBy(() -> executor.setContext(null, axPolicy, internalContextMock))
+            .hasMessage("state finalizer logic on task reference "
+                + "\"AxStateTaskReference:(stateKey=AxReferenceKey:(parentKeyName=Policy,"
+                + "parentKeyVersion=0.0.1,parentLocalName=state1,localName=str1),"
+                + "outputType=LOGIC,output=AxReferenceKey:(parentKeyName=Policy,parentKeyVersion=0.0.1,"
+                + "parentLocalName=state1,localName=sfl))\" on state \"Policy:0.0.1:NULL:state1\" " + "does not exist");
+        axPolicy.getStateMap().get("State1").getStateFinalizerLogicMap().put("sfl", savedSfl);
+        executor.setContext(null, axPolicy, internalContextMock);
+
+        DummyTaskSelectExecutor.setTaskNo(0);
+        executor.execute(0, null, incomingEventMock);
+
+        AxArtifactKey task1Key = new AxArtifactKey("task1:0.0.1");
+        axPolicy.getStateMap().get("State1").getTaskReferences().get(task1Key)
+            .setStateTaskOutputType(AxStateTaskOutputType.UNDEFINED);
+        assertThatThrownBy(() -> executor.setContext(null, axPolicy, internalContextMock))
+            .hasMessage("invalid state output type on task reference \"AxStateTaskReference:(stateKey"
+                + "=AxReferenceKey:(parentKeyName=Policy,parentKeyVersion=0.0.1,parentLocalName=state1,localName=str1),"
+                + "outputType=UNDEFINED,output=AxReferenceKey:(parentKeyName=Policy,"
+                + "parentKeyVersion=0.0.1,parentLocalName=state1,localName=sfl))\" "
+                + "on state \"Policy:0.0.1:NULL:state1\"");
+        axPolicy.getStateMap().get("State1").getTaskReferences().get(task1Key)
+            .setStateTaskOutputType(AxStateTaskOutputType.LOGIC);
+        executor.setContext(null, axPolicy, internalContextMock);
+
+        DummyTaskSelectExecutor.setTaskNo(0);
+        executor.execute(0, null, incomingEventMock);
+
+        DummyTaskSelectExecutor.setTaskNo(0);
+        dummySfle.setReturnBad(true);
+        assertThatThrownBy(() -> executor.execute(0, null, incomingEventMock))
+            .hasMessage("State execution of state \"Policy:0.0.1:NULL:state1\" on task \"task1:0.0.1\""
+                + " failed: state output definition for state output \"stateOutputBad\" not found for "
+                + "state \"Policy:0.0.1:NULL:state1\"");
+        DummyTaskSelectExecutor.setTaskNo(0);
+        dummySfle.setReturnBad(false);
+        executor.execute(0, null, incomingEventMock);
+
+        assertThatThrownBy(executor::cleanUp)
+            .hasMessage("cleanUp() not implemented on class");
+    }
+
+    @Test
+    public void testStateOutput() throws StateMachineException {
+        final StateOutput output =
+            new StateOutput(axPolicy.getStateMap().get("State0").getStateOutputs().get("stateOutput0"));
+        assertNotNull(output);
+
+        assertEquals("stateOutput0", output.getStateOutputDefinition().getKey().getLocalName());
+
+        assertThatThrownBy(() -> output.setEventFields(null, null))
+            .hasMessage("incomingFieldDefinitionMap may not be null");
+        Map<String, AxEvent> incomingFieldDefinitionMap = new LinkedHashMap<>();
+        assertThatThrownBy(() -> output.setEventFields(incomingFieldDefinitionMap, null))
+            .hasMessage("eventFieldMaps may not be null");
+        Map<String, Map<String, Object>> eventFieldMaps = new LinkedHashMap<>();
+        output.setEventFields(incomingFieldDefinitionMap, eventFieldMaps);
+        AxEvent event = new AxEvent(new AxArtifactKey("Event1", "0.0.1"));
+        event.setParameterMap(Map.of("key", new AxField()));
+        incomingFieldDefinitionMap.put("Event1", event);
+        eventFieldMaps.put("Event1", Map.of("key2", "value"));
+        assertThatThrownBy(() -> output.setEventFields(incomingFieldDefinitionMap, eventFieldMaps))
+            .hasMessage("field definitions and values do not match for event Event1:0.0.1\n[key]\n[key2]");
+
+        eventFieldMaps.put("Event1", Map.of("key", "value"));
+        assertThatThrownBy(() -> output.setEventFields(incomingFieldDefinitionMap, eventFieldMaps))
+            .hasMessage("field \"key\" does not exist on event \"Event1:0.0.1\"");
+
+        incomingFieldDefinitionMap.clear();
+        eventFieldMaps.clear();
+        AxArtifactKey stringSchemaKey = new AxArtifactKey("StringSchema:0.0.1");
+        AxReferenceKey fieldKey = new AxReferenceKey("Event1:0.0.1:event:Field0");
+        AxField event1Field0Definition = new AxField(fieldKey, stringSchemaKey);
+        event.setParameterMap(Map.of("Event1Field0", event1Field0Definition));
+        incomingFieldDefinitionMap.put("Event1", event);
+        eventFieldMaps.put("Event1", Map.of("Event1Field0", "Value"));
+        output.setEventFields(incomingFieldDefinitionMap, eventFieldMaps);
+
+        StateOutput outputCopy = new StateOutput(axPolicy.getStateMap().get("State0")
+                .getStateOutputs().get("stateOutput0"));
+
+        EnEvent incomingEvent = new EnEvent(new AxArtifactKey("Event0:0.0.1"));
+        outputCopy.copyUnsetFields(incomingEvent);
+        incomingEvent.put("Event1Field0", "Hello");
+        outputCopy.copyUnsetFields(incomingEvent);
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskExecutorTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskExecutorTest.java
new file mode 100644
index 000000000..4160a9f19
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskExecutorTest.java
@@ -0,0 +1,240 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor;
+
+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 java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.TreeMap;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.TaskParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.eventmodel.concepts.AxField;
+import org.onap.policy.apex.model.eventmodel.concepts.AxInputField;
+import org.onap.policy.apex.model.eventmodel.concepts.AxOutputField;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskLogic;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskParameter;
+
+/**
+ * Test task excutor.
+ */
+public class TaskExecutorTest {
+    @Mock
+    private AxTask axTaskMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private AxInputField axInputFieldMock;
+
+    @Mock
+    private AxInputField axOptionalInputFieldMock;
+
+    @Mock
+    private AxOutputField axOutputFieldMock;
+
+    @Mock
+    private AxOutputField axOptionalOutputFieldMock;
+
+    @Mock
+    private AxOutputField axMissingOutputFieldMock;
+
+    @Mock
+    private Executor<Map<String, Object>, Map<String, Map<String, Object>>, AxTask,
+        ApexInternalContext> nextExecutorMock;
+
+    @Mock
+    private AxTaskLogic taskLogicMock;
+
+    private Map<String, AxField> inFieldMap;
+    private Map<String, AxField> outFieldMap;
+    private List<TaskParameters> taskParametersFromConfig;
+    private Map<String, AxEvent> outEvents = new TreeMap<>();
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        AxArtifactKey task0Key = new AxArtifactKey("Task0:0.0.1");
+        Mockito.doReturn(task0Key).when(axTaskMock).getKey();
+        Mockito.doReturn(task0Key.getId()).when(axTaskMock).getId();
+
+        inFieldMap = Map.of("InField0", axInputFieldMock, "InField1", axOptionalInputFieldMock);
+        outFieldMap = new LinkedHashMap<>();
+
+        outFieldMap.put("OutField0", axOutputFieldMock);
+        outFieldMap.put("OutField1", axOptionalOutputFieldMock);
+
+        AxEvent inEvent = new AxEvent();
+        inEvent.setParameterMap(inFieldMap);
+        AxEvent outEvent = new AxEvent(new AxArtifactKey("outputEvent:1.0.0"));
+        outEvent.setParameterMap(outFieldMap);
+        outEvents.put(outEvent.getKey().getName(), outEvent);
+
+        AxArtifactKey schemaKey = new AxArtifactKey("Schema:0.0.1");
+        Mockito.doReturn(schemaKey).when(axInputFieldMock).getSchema();
+        Mockito.doReturn(schemaKey).when(axOptionalInputFieldMock).getSchema();
+        Mockito.doReturn(schemaKey).when(axOutputFieldMock).getSchema();
+        Mockito.doReturn(schemaKey).when(axOptionalOutputFieldMock).getSchema();
+        Mockito.doReturn(schemaKey).when(axMissingOutputFieldMock).getSchema();
+
+        Mockito.doReturn(true).when(axOptionalInputFieldMock).getOptional();
+        Mockito.doReturn(true).when(axOptionalOutputFieldMock).getOptional();
+        Mockito.doReturn(false).when(axMissingOutputFieldMock).getOptional();
+
+        Mockito.doReturn(taskLogicMock).when(axTaskMock).getTaskLogic();
+
+        Mockito.doReturn(inEvent).when(axTaskMock).getInputEvent();
+        Mockito.doReturn(outEvents).when(axTaskMock).getOutputEvents();
+
+        Mockito.doReturn(new AxArtifactKey("Context:0.0.1")).when(internalContextMock).getKey();
+
+        Map<String, AxTaskParameter> taskParameters = new HashMap<>();
+        taskParameters.put("parameterKey2", new AxTaskParameter(new AxReferenceKey(), "parameterOriginalValue2"));
+        Mockito.doReturn(taskParameters).when(axTaskMock).getTaskParameters();
+
+        taskParametersFromConfig = new ArrayList<>();
+        taskParametersFromConfig.add(new TaskParameters("parameterKey0", "parameterNewValue0", "Task0:0.0.1"));
+        taskParametersFromConfig.add(new TaskParameters("parameterKey1", "parameterNewValue1", "Task1:0.0.1"));
+        taskParametersFromConfig.add(new TaskParameters("parameterKey2", "parameterNewValue2", null));
+    }
+
+    @Test
+    public void testTaskExecutor() throws StateMachineException, ContextException {
+        final DummyTaskExecutor executor = new DummyTaskExecutor();
+        executor.setContext(null, axTaskMock, internalContextMock);
+        assertEquals("Task0:0.0.1", executor.getKey().getId());
+        assertEquals(null, executor.getExecutionContext());
+        assertEquals(null, executor.getParent());
+        assertEquals(internalContextMock, executor.getContext());
+        assertEquals(null, executor.getNext());
+        assertEquals(null, executor.getIncoming());
+        assertEquals(null, executor.getOutgoing());
+        assertNotNull(executor.getSubject());
+
+        executor.setParameters(new ExecutorParameters());
+        executor.setNext(nextExecutorMock);
+        assertEquals(nextExecutorMock, executor.getNext());
+        executor.setNext(null);
+        assertEquals(null, executor.getNext());
+
+        assertThatThrownBy(() -> executor.cleanUp()).hasMessageContaining("cleanUp() not implemented on class");
+
+        Mockito.doReturn(null).when(taskLogicMock).getLogic();
+
+        assertThatThrownBy(() -> executor.prepare()).hasMessageContaining("task logic cannot be null.");
+
+        Mockito.doReturn("some task logic").when(taskLogicMock).getLogic();
+
+        executor.prepare();
+
+        Map<String, Object> incomingFields = new LinkedHashMap<>();
+
+        incomingFields.put("InField0", "A Value");
+
+        executor.executePre(0, new Properties(), incomingFields);
+
+        assertThatThrownBy(() -> executor.execute(0, new Properties(), incomingFields))
+            .hasMessageContaining("execute() not implemented on abstract TaskExecutor class, only on its subclasses");
+
+        assertThatThrownBy(() -> executor.executePost(false)).hasMessageContaining(
+            "execute-post: task logic execution failure on task \"Task0\" in model Context:0.0.1");
+
+        executor.getExecutionContext().setMessage("Execution message");
+
+        assertThatThrownBy(() -> executor.executePost(false)).hasMessageContaining(
+            "execute-post: task logic execution failure on task \"Task0\" in model Context:0.0.1, "
+                + "user message: Execution message");
+
+        executor.executePost(true);
+
+        outFieldMap.put("MissingField", axMissingOutputFieldMock);
+        outEvents.get("outputEvent").getParameterMap().put("MissingField", axMissingOutputFieldMock);
+        assertThatThrownBy(() -> executor.executePost(true)).hasMessageContaining(
+            "Fields for task output events \"[outputEvent]\" are missing for task \"Task0:0.0.1\"");
+
+        outFieldMap.remove("MissingField");
+        outEvents.get("outputEvent").getParameterMap().remove("MissingField");
+        executor.getExecutionContext().outFields.put("BadExtraField", "Howdy!");
+
+        assertThatThrownBy(() -> executor.executePost(true)).hasMessageContaining(
+            "task output event \"[outputEvent]\" contains fields that are unwanted for task \"Task0:0.0.1\"");
+
+        executor.getExecutionContext().outFields.remove("BadExtraField");
+        outFieldMap.put("InField1", axMissingOutputFieldMock);
+        executor.executePost(true);
+
+        outFieldMap.put("InField0", axMissingOutputFieldMock);
+        executor.executePost(true);
+
+        executor.getExecutionContext().outFields.put("InField0", "Output Value");
+        outEvents.get("outputEvent").getParameterMap().put("InField0", axMissingOutputFieldMock);
+        executor.executePost(true);
+
+        executor.getExecutionContext().outFields.remove("InField0");
+        executor.executePost(true);
+
+        assertThatThrownBy(() -> executor.executePre(0, null, incomingFields))
+            .hasMessageMatching("^executionProperties is marked .*on.*ull but is null$");
+    }
+
+    @Test
+    public void testTaskExecutorForTaskParameters() {
+        DummyTaskExecutor executorForParmeterTest = new DummyTaskExecutor(false);
+
+        executorForParmeterTest.setContext(null, axTaskMock, internalContextMock);
+        executorForParmeterTest.updateTaskParameters(taskParametersFromConfig);
+        assertNotNull(executorForParmeterTest.getSubject().getTaskParameters());
+        // taskId matched, parameter value updated with the new value
+        assertEquals("parameterNewValue0",
+            executorForParmeterTest.getSubject().getTaskParameters().get("parameterKey0").getTaskParameterValue());
+        // taskId mismatch, so the parameter is not updated in the task
+        assertNull(executorForParmeterTest.getSubject().getTaskParameters().get("parameterKey1"));
+        // taskId is not available, so parameter is updated in the task
+        assertEquals("parameterNewValue2",
+            executorForParmeterTest.getSubject().getTaskParameters().get("parameterKey2").getTaskParameterValue());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskSelectExecutorTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskSelectExecutorTest.java
new file mode 100644
index 000000000..613d1ae01
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/TaskSelectExecutorTest.java
@@ -0,0 +1,148 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Properties;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateTaskReference;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskSelectionLogic;
+
+/**
+ * Test task executor.
+ */
+public class TaskSelectExecutorTest {
+    @Mock
+    private AxState axStateMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private Executor<EnEvent, AxArtifactKey, AxState, ApexInternalContext> nextExecutorMock;
+
+    @Mock
+    private AxTaskSelectionLogic taskSelectionLogicMock;
+
+    @Mock
+    private EnEvent incomingEvent;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        AxReferenceKey state0Key = new AxReferenceKey("State0Parent:0.0.1:Parent:State0");
+        Mockito.doReturn(state0Key).when(axStateMock).getKey();
+        Mockito.doReturn(state0Key.getId()).when(axStateMock).getId();
+
+        Map<AxArtifactKey, AxStateTaskReference> taskReferences = new LinkedHashMap<>();
+        taskReferences.put(new AxArtifactKey("Task0:0.0.0"), null);
+        taskReferences.put(new AxArtifactKey("Task1:0.0.0"), null);
+        Mockito.doReturn(taskReferences).when(axStateMock).getTaskReferences();
+        Mockito.doReturn(new AxArtifactKey("Task1:0.0.0")).when(axStateMock).getDefaultTask();
+
+        Mockito.doReturn(taskSelectionLogicMock).when(axStateMock).getTaskSelectionLogic();
+
+        Mockito.doReturn(new AxArtifactKey("Context:0.0.1")).when(internalContextMock).getKey();
+    }
+
+    @Test
+    public void testTaskSelectionExecutor() throws StateMachineException {
+        DummyTaskSelectExecutor executor = new DummyTaskSelectExecutor();
+
+        executor.setContext(null, axStateMock, internalContextMock);
+        assertEquals("State0Parent:0.0.1:Parent:State0", executor.getKey().getId());
+        assertEquals(null, executor.getExecutionContext());
+        assertEquals(null, executor.getParent());
+        assertEquals(internalContextMock, executor.getContext());
+        assertEquals(null, executor.getNext());
+        assertEquals(null, executor.getIncoming());
+        assertEquals(null, executor.getOutgoing());
+        assertEquals(axStateMock, executor.getSubject());
+
+        executor.setParameters(new ExecutorParameters());
+        executor.setNext(nextExecutorMock);
+        assertEquals(nextExecutorMock, executor.getNext());
+        executor.setNext(null);
+        assertEquals(null, executor.getNext());
+
+        assertThatThrownBy(executor::cleanUp)
+            .hasMessage("cleanUp() not implemented on class");
+        Mockito.doReturn(null).when(taskSelectionLogicMock).getLogic();
+
+        assertThatThrownBy(executor::prepare)
+            .hasMessage("task selection logic cannot be null.");
+        Mockito.doReturn("some task logic").when(taskSelectionLogicMock).getLogic();
+
+        executor.prepare();
+
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        assertThatThrownBy(() -> executor.execute(0, new Properties(), incomingEvent))
+            .hasMessage("execute() not implemented on class");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessage("execute-post: task selection logic failed on state \"State0Parent:0.0.1:Parent:State0\"");
+
+        executor.getExecutionContext().setMessage("Execution message");
+        assertThatThrownBy(() -> executor.executePost(false))
+            .hasMessageContaining("execute-post: task selection logic failed on state \""
+                + "State0Parent:0.0.1:Parent:State0\", user message: Execution message");
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        executor.executePost(true);
+        assertEquals("Task1", executor.getOutgoing().getName());
+
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        executor.getOutgoing().setName("IDontExist");
+        assertThatThrownBy(() -> executor.executePost(true))
+            .hasMessageContaining("task \"IDontExist:0.0.0\" returned by task selection logic not defined "
+                + "on state \"State0Parent:0.0.1:Parent:State0\"");
+        executor.executePre(0, new Properties(), incomingEvent);
+
+        executor.getOutgoing().setName("Task0");
+
+        executor.executePost(true);
+        assertEquals("Task0", executor.getOutgoing().getName());
+
+        assertThatThrownBy(() -> executor.executePre(0, null, incomingEvent))
+            .hasMessageMatching("^executionProperties is marked .*on.*ull but is null$");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxStateFacadeTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxStateFacadeTest.java
new file mode 100644
index 000000000..68d478877
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxStateFacadeTest.java
@@ -0,0 +1,86 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor.context;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+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.service.ModelService;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.apex.model.policymodel.concepts.AxTasks;
+
+/**
+ * Test the state facade.
+ */
+public class AxStateFacadeTest {
+    @Mock
+    private AxState axStateMock;
+
+    @Mock
+    private AxTask axTaskMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+        
+        AxReferenceKey stateKey = new AxReferenceKey("StateParent:0.0.1:ParentName:StateName");
+        Mockito.doReturn(stateKey).when(axStateMock).getKey();
+
+        AxArtifactKey task0Key = new AxArtifactKey("Task0:0.0.1");
+        Mockito.doReturn(task0Key).when(axStateMock).getDefaultTask();
+        
+        Map<AxArtifactKey, Object> taskReferences = new LinkedHashMap<>();;
+        taskReferences.put(task0Key, null);
+        Mockito.doReturn(taskReferences).when(axStateMock).getTaskReferences();
+
+        AxTasks tasks = new AxTasks();
+        tasks.getTaskMap().put(task0Key, axTaskMock);
+        
+        ModelService.registerModel(AxTasks.class, tasks);
+        Mockito.doReturn(task0Key).when(axTaskMock).getKey();
+    }
+
+    @Test
+    public void testAxStateFacade() {
+        AxStateFacade stateFacade = new AxStateFacade(axStateMock);
+        
+        assertEquals("StateName", stateFacade.getStateName());
+        assertEquals("StateParent:0.0.1:ParentName:StateName", stateFacade.getId());
+        
+        assertEquals("Task0", stateFacade.getDefaultTaskKey().getName());
+        assertNull(stateFacade.getTaskKey(null));
+        assertEquals("Task0", stateFacade.getTaskKey("Task0").getName());
+        stateFacade.getTaskNames();
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxTaskFacadeTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxTaskFacadeTest.java
new file mode 100644
index 000000000..9da8ecfad
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/AxTaskFacadeTest.java
@@ -0,0 +1,140 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor.context;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.util.Map;
+import java.util.TreeMap;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.parameters.ContextParameterConstants;
+import org.onap.policy.apex.context.parameters.SchemaParameters;
+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.service.ModelService;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchema;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextSchemas;
+import org.onap.policy.apex.model.eventmodel.concepts.AxEvent;
+import org.onap.policy.apex.model.eventmodel.concepts.AxField;
+import org.onap.policy.apex.model.eventmodel.concepts.AxInputField;
+import org.onap.policy.apex.model.eventmodel.concepts.AxOutputField;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the state facade.
+ */
+public class AxTaskFacadeTest {
+    @Mock
+    private AxTask axTaskMock;
+
+    @Mock
+    private AxInputField axInputFieldMock;
+
+    @Mock
+    private AxInputField axInputFieldBadMock;
+
+    @Mock
+    private AxOutputField axOutputFieldMock;
+
+    @Mock
+    private AxOutputField axOutputFieldBadMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        AxContextSchemas schemas = new AxContextSchemas();
+
+        AxArtifactKey stringTypeKey = new AxArtifactKey("StringType:0.0.1");
+        AxContextSchema stringType = new AxContextSchema(stringTypeKey, "Java", "java.lang.String");
+        schemas.getSchemasMap().put(stringTypeKey, stringType);
+
+        ModelService.registerModel(AxContextSchemas.class, schemas);
+
+        MockitoAnnotations.initMocks(this);
+
+        AxArtifactKey task0Key = new AxArtifactKey("Task0:0.0.1");
+        Mockito.doReturn(task0Key).when(axTaskMock).getKey();
+        Mockito.doReturn(task0Key.getId()).when(axTaskMock).getId();
+
+        Map<String, AxField> inFieldMap = Map.of("InField0", axInputFieldMock, "InFieldBad", axInputFieldBadMock);
+        Map<String, AxField> outFieldMap = Map.of("OutField0", axOutputFieldMock, "OutFieldBad", axOutputFieldBadMock);
+
+        AxEvent inEvent = new AxEvent();
+        inEvent.setParameterMap(inFieldMap);
+        AxEvent outEvent = new AxEvent(new AxArtifactKey("outputEvent:1.0.0"));
+        outEvent.setParameterMap(outFieldMap);
+        Map<String, AxEvent> outEvents = new TreeMap<>();
+        outEvents.put(outEvent.getKey().getName(), outEvent);
+
+        Mockito.doReturn(inEvent).when(axTaskMock).getInputEvent();
+        Mockito.doReturn(outEvents).when(axTaskMock).getOutputEvents();
+
+        Mockito.doReturn(new AxReferenceKey(task0Key, "InField0")).when(axInputFieldMock).getKey();
+        Mockito.doReturn(stringTypeKey).when(axInputFieldMock).getSchema();
+
+        Mockito.doReturn(new AxReferenceKey(task0Key, "OutField0")).when(axOutputFieldMock).getKey();
+        Mockito.doReturn(stringTypeKey).when(axOutputFieldMock).getSchema();
+
+        ParameterService.register(new SchemaParameters());
+    }
+
+    @After
+    public void teardown() {
+        ParameterService.deregister(ContextParameterConstants.SCHEMA_GROUP_NAME);
+        ModelService.clear();
+    }
+
+    @Test
+    public void testAxStateFacade() {
+        AxTaskFacade taskFacade = new AxTaskFacade(axTaskMock);
+
+        assertEquals("Task0", taskFacade.getTaskName());
+        assertEquals("Task0:0.0.1", taskFacade.getId());
+
+        assertThatThrownBy(() -> taskFacade.getInFieldSchemaHelper("InFieldDoesntExist"))
+            .hasMessage("no incoming field with name \"InFieldDoesntExist\" " + "defined on task "
+                    + "\"Task0:0.0.1\"");
+        assertThatThrownBy(() -> taskFacade.getOutFieldSchemaHelper("OutFieldDoesntExist"))
+            .hasMessage("no outgoing field with name \"OutFieldDoesntExist\" " + "defined on task "
+                    + "\"Task0:0.0.1\"");
+        assertNotNull(taskFacade.getInFieldSchemaHelper("InField0"));
+        assertNotNull(taskFacade.getOutFieldSchemaHelper("OutField0"));
+
+        assertThatThrownBy(() -> taskFacade.getInFieldSchemaHelper("InFieldBad"))
+            .hasMessage("schema helper cannot be created for task field \"InFieldBad\" "
+                    + "with key \"null\" with schema \"null\"");
+        assertThatThrownBy(() -> taskFacade.getOutFieldSchemaHelper("OutFieldBad"))
+            .hasMessage("schema helper cannot be created for task field \"OutFieldBad\" "
+                    + "with key \"null\" with schema \"null\"");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/DummyContextAlbum.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/DummyContextAlbum.java
new file mode 100644
index 000000000..efb53a682
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/DummyContextAlbum.java
@@ -0,0 +1,226 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor.context;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+import lombok.AllArgsConstructor;
+import org.apache.commons.lang3.NotImplementedException;
+import org.onap.policy.apex.context.ContextAlbum;
+import org.onap.policy.apex.context.ContextException;
+import org.onap.policy.apex.context.SchemaHelper;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
+import org.onap.policy.apex.model.contextmodel.concepts.AxContextAlbum;
+
+/**
+ * Dummy context album for testing.
+ */
+@AllArgsConstructor
+public class DummyContextAlbum implements ContextAlbum {
+    private final AxArtifactKey key;
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void clear() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean containsKey(Object key) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean containsValue(Object value) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Set<Entry<String, Object>> entrySet() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Object get(Object key) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean isEmpty() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Set<String> keySet() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Object put(String key, Object value) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void putAll(Map<? extends String, ? extends Object> map) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Object remove(Object key) {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public int size() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public Collection<Object> values() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxArtifactKey getKey() {
+        return key;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String getName() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxContextAlbum getAlbumDefinition() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public SchemaHelper getSchemaHelper() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void lockForReading(String key) throws ContextException {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void lockForWriting(String key) throws ContextException {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void unlockForReading(String key) throws ContextException {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void unlockForWriting(String key) throws ContextException {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public AxConcept[] getUserArtifactStack() {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void setUserArtifactStack(AxConcept[] userArtifactStack) {
+        // Do nothing
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void flush() throws ContextException {
+        throw new NotImplementedException("Not implemented on dummy class");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/StateFinalizerExecutionContextTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/StateFinalizerExecutionContextTest.java
new file mode 100644
index 000000000..c540f51ad
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/StateFinalizerExecutionContextTest.java
@@ -0,0 +1,109 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor.context;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextAlbum;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.executor.StateFinalizerExecutor;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+
+/**
+ * Test Task Execution Context.
+ */
+public class StateFinalizerExecutionContextTest {
+    @Mock
+    private StateFinalizerExecutor stateFinalizerExecutorMock;
+
+    @Mock
+    private StateFinalizerExecutor parentExecutorMock;
+
+    @Mock
+    private AxState axStateMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        Set<AxArtifactKey> contextAlbumReferences = new LinkedHashSet<>();
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey0:0.0.1")));
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey1:0.0.1")));
+
+        Mockito.doReturn(contextAlbumReferences).when(axStateMock).getContextAlbumReferences();
+        Mockito.doReturn(new AxReferenceKey("Parent:0.0.1:ParentName:StateName")).when(axStateMock).getKey();
+
+        Map<AxArtifactKey, ContextAlbum> contextAlbumMap = new LinkedHashMap<>();
+        AxArtifactKey album0Key = new AxArtifactKey("AlbumKey0:0.0.1");
+        AxArtifactKey album1Key = new AxArtifactKey("AlbumKey1:0.0.1");
+
+        contextAlbumMap.put(album0Key, new DummyContextAlbum(album0Key));
+        contextAlbumMap.put(album1Key, new DummyContextAlbum(album1Key));
+
+        Mockito.doReturn(contextAlbumMap).when(internalContextMock).getContextAlbums();
+
+        Mockito.doReturn(parentExecutorMock).when(stateFinalizerExecutorMock).getParent();
+        Mockito.doReturn(new AxReferenceKey("Parent:0.0.1:ParentName:LocalName")).when(parentExecutorMock).getKey();
+    }
+
+    @Test
+    public void test() {
+        final Map<String, Object> fields = new LinkedHashMap<>();
+        final Set<String> stateOutputNames = new LinkedHashSet<>();
+
+        StateFinalizerExecutionContext sfec = new StateFinalizerExecutionContext(stateFinalizerExecutorMock, 0, null,
+                        axStateMock, fields, stateOutputNames, internalContextMock);
+
+        assertNotNull(sfec);
+        sfec.setMessage("SFEC Message");
+        assertEquals("SFEC Message", sfec.getMessage());
+
+        sfec.setSelectedStateOutputName("SomeOutput");
+        assertEquals("SomeOutput", sfec.getSelectedStateOutputName());
+
+        ContextAlbum contextAlbum = sfec.getContextAlbum("AlbumKey0");
+        assertEquals("AlbumKey0:0.0.1", contextAlbum.getKey().getId());
+
+        assertThatThrownBy(() -> sfec.getContextAlbum("AlbumKeyNonExistant"))
+            .hasMessage("cannot find definition of context album \"AlbumKeyNonExistant\" "
+                            + "on state \"Parent:0.0.1:ParentName:StateName\"");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskExecutionContextTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskExecutionContextTest.java
new file mode 100644
index 000000000..24c504822
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskExecutionContextTest.java
@@ -0,0 +1,118 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 Nordix Foundation.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor.context;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextAlbum;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.executor.TaskExecutor;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskParameter;
+
+/**
+ * Test Task Execution Context.
+ */
+public class TaskExecutionContextTest {
+    @Mock
+    private TaskExecutor taskExecutorMock;
+
+    @Mock
+    private TaskExecutor parentExecutorMock;
+
+    @Mock
+    private AxTask axTaskMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        Set<AxArtifactKey> contextAlbumReferences = new LinkedHashSet<>();
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey0:0.0.1")));
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey1:0.0.1")));
+
+        Mockito.doReturn(contextAlbumReferences).when(axTaskMock).getContextAlbumReferences();
+
+        Map<String, AxTaskParameter> taskParameters = new HashMap<>();
+        taskParameters.put("parameterKey1", new AxTaskParameter(new AxReferenceKey(), "parameterValue1"));
+        taskParameters.put("parameterKey2", new AxTaskParameter(new AxReferenceKey(), "parameterValue2"));
+        Mockito.doReturn(taskParameters).when(axTaskMock).getTaskParameters();
+
+        Map<AxArtifactKey, ContextAlbum> contextAlbumMap = new LinkedHashMap<>();
+        AxArtifactKey album0Key = new AxArtifactKey("AlbumKey0:0.0.1");
+        AxArtifactKey album1Key = new AxArtifactKey("AlbumKey1:0.0.1");
+
+        contextAlbumMap.put(album0Key, new DummyContextAlbum(album0Key));
+        contextAlbumMap.put(album1Key, new DummyContextAlbum(album1Key));
+
+        Mockito.doReturn(contextAlbumMap).when(internalContextMock).getContextAlbums();
+
+        Mockito.doReturn(parentExecutorMock).when(taskExecutorMock).getParent();
+        Mockito.doReturn(new AxArtifactKey("Parent:0.0.1")).when(parentExecutorMock).getKey();
+    }
+
+    @Test
+    public void test() {
+        final Map<String, Object> inFields = new LinkedHashMap<>();
+        final List<Map<String, Object>> outFieldsList = new LinkedList<>();
+
+        TaskExecutionContext tec = new TaskExecutionContext(taskExecutorMock, 0, null, axTaskMock, inFields,
+            outFieldsList, internalContextMock);
+
+        assertNotNull(tec);
+        tec.setMessage("TEC Message");
+        assertEquals("TEC Message", tec.getMessage());
+
+        ContextAlbum contextAlbum = tec.getContextAlbum("AlbumKey0");
+        assertEquals("AlbumKey0:0.0.1", contextAlbum.getKey().getId());
+
+        Map<String, String> parameters = tec.getParameters();
+        assertEquals("parameterValue1", parameters.get("parameterKey1"));
+        assertEquals("parameterValue2", parameters.get("parameterKey2"));
+
+        assertThatThrownBy(() -> tec.getContextAlbum("AlbumKeyNonExistant"))
+            .hasMessageContaining("cannot find definition of context album \"AlbumKeyNonExistant\" on task \"null\"");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskSelectionExecutionContextTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskSelectionExecutionContextTest.java
new file mode 100644
index 000000000..5857e0513
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/context/TaskSelectionExecutionContextTest.java
@@ -0,0 +1,109 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor.context;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.context.ContextAlbum;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.event.EnEvent;
+import org.onap.policy.apex.core.engine.executor.TaskSelectExecutor;
+import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
+import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+
+/**
+ * Test Task Execution Context.
+ */
+public class TaskSelectionExecutionContextTest {
+    @Mock
+    private TaskSelectExecutor taskSelectExecutorMock;
+
+    @Mock
+    private TaskSelectExecutor parentExecutorMock;
+
+    @Mock
+    private AxState axStateMock;
+
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private EnEvent incomingEventMock;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        Set<AxArtifactKey> contextAlbumReferences = new LinkedHashSet<>();
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey0:0.0.1")));
+        contextAlbumReferences.add(new AxArtifactKey(("AlbumKey1:0.0.1")));
+
+        Mockito.doReturn(contextAlbumReferences).when(axStateMock).getContextAlbumReferences();
+        Mockito.doReturn(new AxReferenceKey("Parent:0.0.1:ParentName:StateName")).when(axStateMock).getKey();
+
+        Map<AxArtifactKey, ContextAlbum> contextAlbumMap = new LinkedHashMap<>();
+        AxArtifactKey album0Key = new AxArtifactKey("AlbumKey0:0.0.1");
+        AxArtifactKey album1Key = new AxArtifactKey("AlbumKey1:0.0.1");
+
+        contextAlbumMap.put(album0Key, new DummyContextAlbum(album0Key));
+        contextAlbumMap.put(album1Key, new DummyContextAlbum(album1Key));
+
+        Mockito.doReturn(contextAlbumMap).when(internalContextMock).getContextAlbums();
+
+        Mockito.doReturn(parentExecutorMock).when(taskSelectExecutorMock).getParent();
+        Mockito.doReturn(new AxReferenceKey("Parent:0.0.1:ParentName:LocalName")).when(parentExecutorMock).getKey();
+    }
+
+    @Test
+    public void test() {
+        final AxArtifactKey outgoingEventKey = new AxArtifactKey("OutEvent:0.0.1");
+
+        TaskSelectionExecutionContext tsec = new TaskSelectionExecutionContext(taskSelectExecutorMock, 0, axStateMock,
+                        incomingEventMock, outgoingEventKey, internalContextMock);
+
+        assertNotNull(tsec);
+        tsec.setMessage("TSEC Message");
+        assertEquals("TSEC Message", tsec.getMessage());
+
+        ContextAlbum contextAlbum = tsec.getContextAlbum("AlbumKey0");
+        assertEquals("AlbumKey0:0.0.1", contextAlbum.getKey().getId());
+
+        assertThatThrownBy(() -> tsec.getContextAlbum("AlbumKeyNonExistant"))
+            .hasMessage("cannot find definition of context album \"AlbumKeyNonExistant\" "
+                            + "on state \"Parent:0.0.1:ParentName:StateName\"");
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/exception/StateMachineRuntimeExceptionTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/exception/StateMachineRuntimeExceptionTest.java
new file mode 100644
index 000000000..84f330308
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/exception/StateMachineRuntimeExceptionTest.java
@@ -0,0 +1,42 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ * ================================================================================
+ * 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.core.engine.executor.exception;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import org.junit.Test;
+
+/**
+ * Test state machine runtime exception.
+ *
+ */
+public class StateMachineRuntimeExceptionTest {
+
+    @Test
+    public void testException() {
+        StateMachineRuntimeException smre = new StateMachineRuntimeException("Exception Message");
+        assertEquals("Exception Message", smre.getMessage());
+        
+        smre = new StateMachineRuntimeException("Exception Message", new IOException());
+        assertEquals("Exception Message", smre.getMessage());
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/engine/executor/impl/ExceutorFactoryImplTest.java b/core/src/test/java/org/onap/policy/apex/core/engine/executor/impl/ExceutorFactoryImplTest.java
new file mode 100644
index 000000000..5957ff347
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/engine/executor/impl/ExceutorFactoryImplTest.java
@@ -0,0 +1,240 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.engine.executor.impl;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.apex.core.engine.EngineParameters;
+import org.onap.policy.apex.core.engine.ExecutorParameters;
+import org.onap.policy.apex.core.engine.context.ApexInternalContext;
+import org.onap.policy.apex.core.engine.executor.Executor;
+import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
+import org.onap.policy.apex.model.policymodel.concepts.AxState;
+import org.onap.policy.apex.model.policymodel.concepts.AxStateFinalizerLogic;
+import org.onap.policy.apex.model.policymodel.concepts.AxTask;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskLogic;
+import org.onap.policy.apex.model.policymodel.concepts.AxTaskSelectionLogic;
+import org.onap.policy.common.parameters.ParameterService;
+
+/**
+ * Test the executor factory implementation.
+ *
+ */
+public class ExceutorFactoryImplTest {
+    @Mock
+    private ApexInternalContext internalContextMock;
+
+    @Mock
+    private AxState stateMock;
+
+    @Mock
+    private AxTaskSelectionLogic tslMock;
+
+    @Mock
+    private AxTask taskMock;
+
+    @Mock
+    private AxTaskLogic tlMock;
+
+    @Mock
+    private AxStateFinalizerLogic sflMock;
+
+    @Mock
+    private Executor<?, ?, ?, ?> parentMock;
+
+    private ExecutorParameters executorPars;
+
+    /**
+     * Set up mocking.
+     */
+    @Before
+    public void startMocking() {
+        MockitoAnnotations.initMocks(this);
+
+        Mockito.doReturn(tslMock).when(stateMock).getTaskSelectionLogic();
+        Mockito.doReturn("Dummy").when(tslMock).getLogicFlavour();
+
+        Mockito.doReturn(tlMock).when(taskMock).getTaskLogic();
+        Mockito.doReturn("Dummy").when(tlMock).getLogicFlavour();
+
+        Mockito.doReturn("Dummy").when(sflMock).getLogicFlavour();
+    }
+
+    @After
+    public void clearPars() {
+        ParameterService.clear();
+    }
+
+    @Test
+    public void testExecutorFactoryImplGood() throws StateMachineException {
+        setGoodPars();
+
+        ExecutorFactoryImpl factory = null;
+
+        factory = new ExecutorFactoryImpl();
+
+        Mockito.doReturn(true).when(stateMock).checkSetTaskSelectionLogic();
+        assertNotNull(factory.getTaskSelectionExecutor(null, stateMock, internalContextMock));
+        Mockito.doReturn(false).when(stateMock).checkSetTaskSelectionLogic();
+        assertNull(factory.getTaskSelectionExecutor(null, stateMock, internalContextMock));
+
+        assertNotNull(factory.getTaskExecutor(null, taskMock, internalContextMock));
+
+        assertNotNull(factory.getStateFinalizerExecutor(parentMock, sflMock, internalContextMock));
+    }
+
+    @Test
+    public void testExecutorFactoryImplNonExistant() {
+        setNonExistantPars();
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Apex executor class not found for executor plugin "
+                            + "\"org.onap.policy.apex.core.engine.executor.BadTaskExecutor\"");
+        executorPars.setTaskExecutorPluginClass(null);
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Apex executor class not found for executor plugin "
+                    + "\"org.onap.policy.apex.core.engine.executor.BadTaskSelectExecutor\"");
+        executorPars.setTaskExecutorPluginClass("org.onap.policy.apex.core.engine.executor.DummyTaskExecutor");
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Apex executor class not found for executor plugin "
+                    + "\"org.onap.policy.apex.core.engine.executor.BadTaskSelectExecutor\"");
+        executorPars.setTaskSelectionExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.DummyTaskSelectExecutor");
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Apex executor class not found for executor plugin "
+                    + "\"org.onap.policy.apex.core.engine.executor.BadStateFinalizerExecutor\"");
+    }
+
+    @Test
+    public void testExecutorFactoryImplBad() {
+        setBadPars();
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Specified Apex executor plugin class \"java.lang.String\" "
+                    + "does not implment the Executor interface");
+        executorPars.setTaskExecutorPluginClass("org.onap.policy.apex.core.engine.executor.DummyTaskExecutor");
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Specified Apex executor plugin class \"java.lang.String\" "
+                    + "does not implment the Executor interface");
+        executorPars.setTaskSelectionExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.DummyTaskSelectExecutor");
+
+        assertThatThrownBy(() -> new ExecutorFactoryImpl())
+            .hasMessage("Specified Apex executor plugin class \"java.lang.String\" "
+                    + "does not implment the Executor interface");
+    }
+
+    @Test
+    public void testExecutorFactoryCreateErrors() throws StateMachineException {
+        setGoodPars();
+
+        executorPars.setTaskExecutorPluginClass(null);
+
+        final ExecutorFactoryImpl factory = new ExecutorFactoryImpl();
+
+        Mockito.doReturn(true).when(stateMock).checkSetTaskSelectionLogic();
+
+        assertThatThrownBy(() -> factory.getTaskExecutor(null, taskMock, internalContextMock))
+            .hasMessage("Executor plugin class not defined for \"Dummy\" executor of type "
+                    + "\"org.onap.policy.apex.core.engine.executor.TaskExecutor\"");
+        executorPars.setTaskExecutorPluginClass("org.onap.policy.apex.core.engine.executor.DummyFailingTaskExecutor");
+
+        ExecutorFactoryImpl factoryInitError = new ExecutorFactoryImpl();
+
+        assertThatThrownBy(() -> factoryInitError.getTaskExecutor(null, taskMock, internalContextMock))
+            .hasMessage("Instantiation error on \"Dummy\" executor of type "
+                    + "\"org.onap.policy.apex.core.engine.executor.DummyFailingTaskExecutor\"");
+        executorPars.setTaskExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.DummyStateFinalizerExecutor");
+
+        ExecutorFactoryImpl factoryDummyError = new ExecutorFactoryImpl();
+
+        assertThatThrownBy(() -> factoryDummyError.getTaskExecutor(null, taskMock, internalContextMock))
+            .hasMessage("Executor on \"Dummy\" "
+                    + "of type \"class org.onap.policy.apex.core.engine.executor.DummyStateFinalizerExecutor\""
+                    + " is not an instance of \"org.onap.policy.apex.core.engine.executor.TaskExecutor\"");
+    }
+
+    /**
+     * Set up good parameters.
+     */
+    private void setGoodPars() {
+        executorPars = new ExecutorParameters();
+        executorPars.setTaskExecutorPluginClass("org.onap.policy.apex.core.engine.executor.DummyTaskExecutor");
+        executorPars.setTaskSelectionExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.DummyTaskSelectExecutor");
+        executorPars.setStateFinalizerExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.DummyStateFinalizerExecutor");
+
+        EngineParameters enginePars = new EngineParameters();
+        enginePars.getExecutorParameterMap().put("Dummy", executorPars);
+
+        ParameterService.register(enginePars);
+        ParameterService.register(executorPars);
+    }
+
+    /**
+     * Set up non existant parameters.
+     */
+    private void setNonExistantPars() {
+        executorPars = new ExecutorParameters();
+        executorPars.setTaskExecutorPluginClass("org.onap.policy.apex.core.engine.executor.BadTaskExecutor");
+        executorPars.setTaskSelectionExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.BadTaskSelectExecutor");
+        executorPars.setStateFinalizerExecutorPluginClass(
+                        "org.onap.policy.apex.core.engine.executor.BadStateFinalizerExecutor");
+
+        EngineParameters enginePars = new EngineParameters();
+        enginePars.getExecutorParameterMap().put("Dummy", executorPars);
+
+        ParameterService.register(enginePars, true);
+        ParameterService.register(executorPars, true);
+    }
+
+    /**
+     * Set up bad parameters.
+     */
+    private void setBadPars() {
+        executorPars = new ExecutorParameters();
+        executorPars.setTaskExecutorPluginClass("java.lang.String");
+        executorPars.setTaskSelectionExecutorPluginClass("java.lang.String");
+        executorPars.setStateFinalizerExecutorPluginClass("java.lang.String");
+
+        EngineParameters enginePars = new EngineParameters();
+        enginePars.getExecutorParameterMap().put("Dummy", executorPars);
+
+        ParameterService.register(enginePars, true);
+        ParameterService.register(executorPars, true);
+    }
+}
diff --git a/core/src/test/java/org/onap/policy/apex/core/infrastructure/threading/ThreadingTest.java b/core/src/test/java/org/onap/policy/apex/core/infrastructure/threading/ThreadingTest.java
new file mode 100644
index 000000000..35ad9386a
--- /dev/null
+++ b/core/src/test/java/org/onap/policy/apex/core/infrastructure/threading/ThreadingTest.java
@@ -0,0 +1,86 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2020 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.core.infrastructure.threading;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Test;
+import org.slf4j.ext.XLogger;
+import org.slf4j.ext.XLoggerFactory;
+
+/**
+ * The Class ThreadingTest.
+ *
+ * @author Liam Fallon (liam.fallon@ericsson.com)
+ */
+public class ThreadingTest {
+
+    private static final String LOCAL_NAME = "localName";
+    // Logger for this class
+    private static final XLogger logger = XLoggerFactory.getXLogger(ThreadingTest.class);
+
+    /**
+     * Test thread factory initialization.
+     */
+    @Test
+    public void testThreadFactoryInitialization() {
+        final ApplicationThreadFactory objUnderTest = new ApplicationThreadFactory(LOCAL_NAME, 0);
+        assertNotNull("Failed to create ApplicationThreadFactory threadFactory0", objUnderTest);
+        logger.debug(objUnderTest.toString());
+        assertTrue("Failed to name ApplicationThreadFactory threadFactory0",
+                objUnderTest.getName().startsWith("Apex-" + LOCAL_NAME));
+
+        final ApplicationThreadFactory objUnderTest1 = new ApplicationThreadFactory(LOCAL_NAME, 0);
+        assertNotNull("Failed to create ApplicationThreadFactory threadFactory1", objUnderTest1);
+        logger.debug(objUnderTest1.toString());
+        assertTrue("Failed to name ApplicationThreadFactory threadFactory1",
+                objUnderTest1.getName().startsWith("Apex-" + LOCAL_NAME));
+
+        testThreadFactory(objUnderTest);
+        testThreadFactory(objUnderTest1);
+    }
+
+    /**
+     * Test thread factory.
+     *
+     * @param threadFactory the thread factory
+     */
+    private void testThreadFactory(final ApplicationThreadFactory threadFactory) {
+        final List<Thread> threadList = new ArrayList<>();
+
+        for (int i = 0; i < 5; i++) {
+            final Thread thread = threadFactory.newThread(() -> {
+            });
+            threadList.add(thread);
+            thread.start();
+        }
+
+        for (int i = 0; i < 5; i++) {
+            Thread thread = threadList.get(i);
+            assertTrue(thread.getName().startsWith("Apex-" + LOCAL_NAME));
+            assertTrue(thread.getName().contains(":" + i));
+        }
+    }
+}