Extend model loader to support model-upgrade (part 1)

- refactor existign code for easier extension
 (no code changes yet, just want to review refactor in this first patch...)
- changed log level of some (error) logging

Issue-ID: CPS-1804
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>
Change-Id: I234ad6c4057e9447cd39a83b8f48799918ca6b7f

7 files changed, 363 insertions, 308 deletions

diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/AbstractModelLoader.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/AbstractModelLoader.java
new file mode 100644
index 000000000..349b1c5b0
--- /dev/null
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/AbstractModelLoader.java
@@ -0,0 +1,139 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 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.cps.ncmp.init;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.time.OffsetDateTime;
+import java.util.Map;
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.onap.cps.api.CpsAdminService;
+import org.onap.cps.api.CpsDataService;
+import org.onap.cps.api.CpsModuleService;
+import org.onap.cps.ncmp.api.impl.exception.NcmpStartUpException;
+import org.onap.cps.spi.exceptions.AlreadyDefinedException;
+import org.onap.cps.utils.JsonObjectMapper;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+abstract class AbstractModelLoader implements ModelLoader {
+
+    private final CpsAdminService cpsAdminService;
+    private final CpsModuleService cpsModuleService;
+    private final CpsDataService cpsDataService;
+
+    private static final int EXIT_CODE_ON_ERROR = 1;
+
+    private final JsonObjectMapper jsonObjectMapper = new JsonObjectMapper(new ObjectMapper());
+
+    @Value("${ncmp.model-loader.maximum-attempt-count:20}")
+    int maximumAttemptCount;
+
+    @Value("${ncmp.timers.model-loader.retry-time-ms:1000}")
+    long retryTimeMs;
+
+    @Override
+    public void onApplicationEvent(@NonNull final ApplicationReadyEvent applicationReadyEvent) {
+        try {
+            onboardOrUpgradeModel();
+        } catch (final NcmpStartUpException ncmpStartUpException) {
+            log.error("Onboarding model for NCMP failed: {} ", ncmpStartUpException.getMessage());
+            SpringApplication.exit(applicationReadyEvent.getApplicationContext(), () -> EXIT_CODE_ON_ERROR);
+        }
+    }
+
+    void waitUntilDataspaceIsAvailable(final String dataspaceName) {
+        int attemptCount = 0;
+        while (cpsAdminService.getDataspace(dataspaceName) == null) {
+            if (attemptCount < maximumAttemptCount) {
+                try {
+                    Thread.sleep(attemptCount * retryTimeMs);
+                    log.info("Retrieving dataspace {} ... {} attempt(s) ", dataspaceName, ++attemptCount);
+                } catch (final InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                }
+            } else {
+                throw new NcmpStartUpException("Retrieval of NCMP dataspace failed",
+                    dataspaceName + " not available (yet)");
+            }
+        }
+    }
+
+    void createSchemaSet(final String dataspaceName, final String schemaSetName, final String resourceName) {
+        try {
+            final Map<String, String> yangResourceContentMap = createYangResourceToContentMap(resourceName);
+            cpsModuleService.createSchemaSet(dataspaceName, schemaSetName, yangResourceContentMap);
+        } catch (final AlreadyDefinedException alreadyDefinedException) {
+            log.warn("Creating new schema set failed as schema set already exists");
+        } catch (final Exception exception) {
+            log.error("Creating schema set for subscription model failed: {} ", exception.getMessage());
+            throw new NcmpStartUpException("Creating schema set failed", exception.getMessage());
+        }
+    }
+
+    void createAnchor(final String dataspaceName, final String schemaSetName, final String anchorName) {
+        try {
+            cpsAdminService.createAnchor(dataspaceName, schemaSetName, anchorName);
+        } catch (final AlreadyDefinedException alreadyDefinedException) {
+            log.warn("Creating new anchor failed as anchor already exists");
+        } catch (final Exception exception) {
+            log.error("Creating anchor for subscription model failed: {} ", exception.getMessage());
+            throw new NcmpStartUpException("Creating anchor failed", exception.getMessage());
+        }
+    }
+
+    void createTopLevelDataNode(final String dataspaceName,
+                                        final String anchorName,
+                                        final String dataNodeName) {
+        final String nodeData = jsonObjectMapper.asJsonString(Map.of(dataNodeName, Map.of()));
+        try {
+            cpsDataService.saveData(dataspaceName, anchorName, nodeData, OffsetDateTime.now());
+        } catch (final AlreadyDefinedException exception) {
+            log.warn("Creating new data node '{}' failed as data node already exists", dataNodeName);
+        } catch (final Exception exception) {
+            log.error("Creating data node for subscription model failed: {}", exception.getMessage());
+            throw new NcmpStartUpException("Creating data node failed", exception.getMessage());
+        }
+    }
+
+    Map<String, String> createYangResourceToContentMap(final String resourceName) {
+        return Map.of(resourceName, getFileContentAsString("models/" + resourceName));
+    }
+
+    private String getFileContentAsString(final String fileName) {
+        try (InputStream inputStream = getClass().getClassLoader().getResourceAsStream(fileName)) {
+            return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
+        } catch (final Exception exception) {
+            final String message = String.format("Onboarding failed as unable to read file: %s", fileName);
+            log.debug(message);
+            throw new NcmpStartUpException(message, exception.getMessage());
+        }
+    }
+
+}
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/ModelLoader.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/ModelLoader.java
index 6f834b702..c61bf1c9b 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/ModelLoader.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/ModelLoader.java
@@ -20,7 +20,6 @@
 
 package org.onap.cps.ncmp.init;
 
-import java.util.Map;
 import lombok.NonNull;
 import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.context.ApplicationListener;
@@ -30,23 +29,6 @@ public interface ModelLoader extends ApplicationListener<ApplicationReadyEvent>
     @Override
     void onApplicationEvent(@NonNull ApplicationReadyEvent applicationReadyEvent);
 
-    /**
-     * Create schema set.
-     *
-     * @param dataspaceName dataspace name
-     * @param schemaSetName schemaset name
-     * @param yangResourceContentMap yang resource content map
-     * @return true if schema set is created
-     */
-    boolean createSchemaSet(String dataspaceName, String schemaSetName, Map<String, String> yangResourceContentMap);
+    void onboardOrUpgradeModel();
 
-    /**
-     * Create anchor.
-     *
-     * @param dataspaceName dataspace name
-     * @param schemaSetName schemaset name
-     * @param anchorName anchor name
-     * @return true if anchor is created
-     */
-    boolean createAnchor(String dataspaceName, String schemaSetName, String anchorName);
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/SubscriptionModelLoader.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/SubscriptionModelLoader.java
index af9ee721c..614efd4f4 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/SubscriptionModelLoader.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/init/SubscriptionModelLoader.java
@@ -20,162 +20,47 @@
 
 package org.onap.cps.ncmp.init;
 
-import java.io.InputStream;
-import java.nio.charset.StandardCharsets;
-import java.time.OffsetDateTime;
-import java.util.Map;
-import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.onap.cps.api.CpsAdminService;
 import org.onap.cps.api.CpsDataService;
 import org.onap.cps.api.CpsModuleService;
-import org.onap.cps.ncmp.api.impl.exception.NcmpStartUpException;
-import org.onap.cps.spi.exceptions.AlreadyDefinedException;
-import org.onap.cps.spi.model.Dataspace;
 import org.springframework.beans.factory.annotation.Value;
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.context.event.ApplicationReadyEvent;
-import org.springframework.stereotype.Component;
+import org.springframework.stereotype.Service;
 
 @Slf4j
-@Component
-@RequiredArgsConstructor
-public class SubscriptionModelLoader implements ModelLoader {
+@Service
+public class SubscriptionModelLoader extends AbstractModelLoader {
 
-    private final CpsAdminService cpsAdminService;
-    private final CpsModuleService cpsModuleService;
-    private final CpsDataService cpsDataService;
     private static final String SUBSCRIPTION_MODEL_FILENAME = "subscription.yang";
-    private static final String SUBSCRIPTION_MODEL_RESOURCE_PATH = "model/" + SUBSCRIPTION_MODEL_FILENAME;
     private static final String SUBSCRIPTION_DATASPACE_NAME = "NCMP-Admin";
     private static final String SUBSCRIPTION_ANCHOR_NAME = "AVC-Subscriptions";
     private static final String SUBSCRIPTION_SCHEMASET_NAME = "subscriptions";
     private static final String SUBSCRIPTION_REGISTRY_DATANODE_NAME = "subscription-registry";
 
-    @Value("${ncmp.model-loader.maximum-attempt-count:20}")
-    private int maximumAttemptCount;
-
-    @Value("${ncmp.timers.model-loader.retry-time-ms:1000}")
-    private long retryTimeMs;
+    public SubscriptionModelLoader(final CpsAdminService cpsAdminService,
+                                   final CpsModuleService cpsModuleService,
+                                   final CpsDataService cpsDataService) {
+        super(cpsAdminService, cpsModuleService, cpsDataService);
+    }
 
     @Value("${ncmp.model-loader.subscription:true}")
     private boolean subscriptionModelLoaderEnabled;
 
-    /**
-     * Method calls boarding subscription model when Application is ready.
-     *
-     * @param applicationReadyEvent the event to respond to
-     */
     @Override
-    public void onApplicationEvent(final ApplicationReadyEvent applicationReadyEvent) {
-        try {
-            if (subscriptionModelLoaderEnabled) {
-                checkNcmpDataspaceExists();
-                onboardSubscriptionModel(createYangResourceToContentMap());
-            } else {
-                log.info("Subscription Model Loader is disabled");
-            }
-        } catch (final NcmpStartUpException ncmpStartUpException) {
-            log.debug("Onboarding model for NCMP failed: {} ", ncmpStartUpException.getMessage());
-            SpringApplication.exit(applicationReadyEvent.getApplicationContext(), () -> 1);
-        }
-    }
-
-    private void checkNcmpDataspaceExists() {
-        boolean ncmpDataspaceExists = false;
-        int attemptCount = 0;
-        while (!ncmpDataspaceExists) {
-            final Dataspace ncmpDataspace = cpsAdminService.getDataspace(SUBSCRIPTION_DATASPACE_NAME);
-            if (ncmpDataspace != null) {
-                ncmpDataspaceExists = true;
-            }
-            if (attemptCount < maximumAttemptCount) {
-                try {
-                    Thread.sleep(attemptCount * retryTimeMs);
-                    attemptCount++;
-                    log.info("Retrieving NCMP dataspace... {} attempt(s) ", attemptCount);
-                } catch (final InterruptedException e) {
-                    Thread.currentThread().interrupt();
-                }
-            } else {
-                throw new NcmpStartUpException("Retrieval of NCMP dataspace fails",
-                    "NCMP dataspace does not exist");
-            }
+    public void onboardOrUpgradeModel() {
+        if (subscriptionModelLoaderEnabled) {
+            waitUntilDataspaceIsAvailable(SUBSCRIPTION_DATASPACE_NAME);
+            onboardSubscriptionModel();
+        } else {
+            log.info("Subscription Model Loader is disabled");
         }
     }
 
-    /**
-     * Method to onboard subscription model for NCMP.
-     */
-    private void onboardSubscriptionModel(final Map<String, String> yangResourceContentMap) {
-        createSchemaSet(SUBSCRIPTION_DATASPACE_NAME, SUBSCRIPTION_SCHEMASET_NAME, yangResourceContentMap);
+    private void onboardSubscriptionModel() {
+        createSchemaSet(SUBSCRIPTION_DATASPACE_NAME, SUBSCRIPTION_SCHEMASET_NAME, SUBSCRIPTION_MODEL_FILENAME);
         createAnchor(SUBSCRIPTION_DATASPACE_NAME, SUBSCRIPTION_SCHEMASET_NAME, SUBSCRIPTION_ANCHOR_NAME);
         createTopLevelDataNode(SUBSCRIPTION_DATASPACE_NAME, SUBSCRIPTION_ANCHOR_NAME,
             SUBSCRIPTION_REGISTRY_DATANODE_NAME);
     }
 
-
-    @Override
-    public boolean createSchemaSet(final String dataspaceName,
-                                   final String schemaSetName,
-                                   final Map<String, String> yangResourceContentMap) {
-        try {
-            cpsModuleService.createSchemaSet(dataspaceName, schemaSetName, yangResourceContentMap);
-        } catch (final AlreadyDefinedException exception) {
-            log.info("Creating new schema set failed as schema set already exists");
-        } catch (final Exception exception) {
-            log.debug("Creating schema set for subscription model failed: {} ", exception.getMessage());
-            throw new NcmpStartUpException("Creating schema set failed", exception.getMessage());
-        }
-        return true;
-    }
-
-    /**
-     * Create Anchor.
-     *
-     * @param dataspaceName dataspace name
-     * @param schemaSetName schema set name
-     * @param anchorName anchor name
-     */
-    @Override
-    public boolean createAnchor(final String dataspaceName, final String schemaSetName,
-                                final String anchorName) {
-        try {
-            cpsAdminService.createAnchor(dataspaceName, schemaSetName, anchorName);
-        } catch (final AlreadyDefinedException exception) {
-            log.info("Creating new anchor failed as anchor already exists");
-        } catch (final Exception exception) {
-            log.debug("Creating anchor for subscription model failed: {} ", exception.getMessage());
-            throw new NcmpStartUpException("Creating anchor failed", exception.getMessage());
-        }
-        return true;
-    }
-
-    private void createTopLevelDataNode(final String dataspaceName,
-                                        final String anchorName,
-                                        final String dataNodeName) {
-        final String nodeData = "{\"" + dataNodeName + "\":{}}";
-        try {
-            cpsDataService.saveData(dataspaceName, anchorName, nodeData, OffsetDateTime.now());
-        } catch (final AlreadyDefinedException exception) {
-            log.info("Creating new data node '{}' failed as data node already exists", dataNodeName);
-        } catch (final Exception exception) {
-            log.debug("Creating data node for subscription model failed: {}", exception.getMessage());
-            throw new NcmpStartUpException("Creating data node failed", exception.getMessage());
-        }
-    }
-
-    private String getFileContentAsString(final String fileName) {
-        try (InputStream inputStream = getClass().getClassLoader().getResourceAsStream(fileName)) {
-            return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
-        } catch (final Exception exception) {
-            final String message = String.format("Onboarding failed as unable to read file: %s", fileName);
-            log.debug(message);
-            throw new NcmpStartUpException(message, exception.getMessage());
-        }
-    }
-
-    private Map<String, String> createYangResourceToContentMap() {
-        return Map.of(SUBSCRIPTION_MODEL_FILENAME, getFileContentAsString(SUBSCRIPTION_MODEL_RESOURCE_PATH));
-    }
 }
diff --git a/cps-ncmp-service/src/main/resources/model/subscription.yang b/cps-ncmp-service/src/main/resources/models/subscription.yang
index 7096c18ab..7096c18ab 100644
--- a/cps-ncmp-service/src/main/resources/model/subscription.yang
+++ b/cps-ncmp-service/src/main/resources/models/subscription.yang
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/AbstractModelLoaderSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/AbstractModelLoaderSpec.groovy
new file mode 100644
index 000000000..a271ca431
--- /dev/null
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/AbstractModelLoaderSpec.groovy
@@ -0,0 +1,191 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 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.cps.ncmp.init
+
+import ch.qos.logback.classic.Level
+import ch.qos.logback.classic.Logger
+import ch.qos.logback.core.read.ListAppender
+import org.onap.cps.api.CpsAdminService
+import org.onap.cps.api.CpsDataService
+import org.onap.cps.api.CpsModuleService
+import org.onap.cps.ncmp.api.impl.exception.NcmpStartUpException
+import org.onap.cps.spi.exceptions.AlreadyDefinedException
+import org.springframework.boot.SpringApplication
+import org.slf4j.LoggerFactory
+import org.springframework.boot.context.event.ApplicationReadyEvent
+import org.springframework.context.annotation.AnnotationConfigApplicationContext
+import spock.lang.Specification
+
+class AbstractModelLoaderSpec extends Specification {
+
+    def mockCpsAdminService = Mock(CpsAdminService)
+    def mockCpsModuleService = Mock(CpsModuleService)
+    def mockCpsDataService = Mock(CpsDataService)
+    def objectUnderTest = Spy(new TestModelLoader(mockCpsAdminService, mockCpsModuleService, mockCpsDataService))
+
+    def applicationContext = new AnnotationConfigApplicationContext()
+
+    def yangResourceToContentMap
+    def logger = (Logger) LoggerFactory.getLogger(AbstractModelLoader)
+    def loggingListAppender
+
+    void setup() {
+        yangResourceToContentMap = objectUnderTest.createYangResourceToContentMap('subscription.yang')
+        logger.setLevel(Level.DEBUG)
+        loggingListAppender = new ListAppender()
+        logger.addAppender(loggingListAppender)
+        loggingListAppender.start()
+        applicationContext.refresh()
+    }
+
+    void cleanup() {
+        ((Logger) LoggerFactory.getLogger(SubscriptionModelLoader.class)).detachAndStopAllAppenders()
+        applicationContext.close()
+    }
+
+    def 'Application ready event'() {
+        when: 'Application (ready) event is triggered'
+            objectUnderTest.onApplicationEvent(Mock(ApplicationReadyEvent))
+        then: 'the onboard/upgrade method is executed'
+            1 * objectUnderTest.onboardOrUpgradeModel()
+    }
+
+    def 'Application ready event with start up exception'() {
+        given: 'a start up exception is thrown doing model onboarding'
+            objectUnderTest.onboardOrUpgradeModel() >> { throw new NcmpStartUpException('test message','details are not logged') }
+        when: 'Application (ready) event is triggered'
+            objectUnderTest.onApplicationEvent(new ApplicationReadyEvent(new SpringApplication(), null, applicationContext, null))
+        then: 'the exception message is logged'
+            def logs = loggingListAppender.list.toString()
+            assert logs.contains('test message')
+    }
+
+    def 'Wait for non-existing dataspace'() {
+        when: 'wait for the dataspace'
+            objectUnderTest.waitUntilDataspaceIsAvailable('some dataspace')
+        then: 'a startup exception is thrown'
+            def thrown = thrown(NcmpStartUpException)
+            assert thrown.message.contains('Retrieval of NCMP dataspace failed')
+    }
+
+    def 'Create schema set.'() {
+        when: 'creating a schema set'
+            objectUnderTest.createSchemaSet('some dataspace','new name','subscription.yang')
+        then: 'the operation is delegated to the admin service'
+            1 * mockCpsModuleService.createSchemaSet('some dataspace','new name',_)
+    }
+
+    def 'Create schema set with already defined exception.'() {
+        given: 'the module service throws an already defined exception'
+            mockCpsModuleService.createSchemaSet(*_) >>  { throw AlreadyDefinedException.forSchemaSet('name','context',null) }
+        when: 'attempt to create a schema set'
+            objectUnderTest.createSchemaSet('some dataspace','new name','subscription.yang')
+        then: 'the exception is ignored i.e. no exception thrown up'
+            noExceptionThrown()
+        and: 'the exception message is logged'
+            def logs = loggingListAppender.list.toString()
+            assert logs.contains('Creating new schema set failed as schema set already exists')
+    }
+
+    def 'Create schema set with non existing yang file.'() {
+        when: 'attempt to create a schema set from a non existing file'
+            objectUnderTest.createSchemaSet('some dataspace','some name','no such yang file')
+        then: 'a startup exception with correct message and details is thrown'
+            def thrown = thrown(NcmpStartUpException)
+            assert thrown.message.contains('Creating schema set failed')
+            assert thrown.details.contains('unable to read file')
+    }
+
+    def 'Create anchor.'() {
+        when: 'creating an anchor'
+            objectUnderTest.createAnchor('some dataspace','some schema set','new name')
+        then: 'thr operation is delegated to the admin service'
+            1 * mockCpsAdminService.createAnchor('some dataspace','some schema set', 'new name')
+    }
+
+    def 'Create anchor with already defined exception.'() {
+        given: 'the admin service throws an already defined exception'
+            mockCpsAdminService.createAnchor(*_)>>  { throw AlreadyDefinedException.forAnchor('name','context',null) }
+        when: 'attempt to create anchor'
+            objectUnderTest.createAnchor('some dataspace','some schema set','new name')
+        then: 'the exception is ignored i.e. no exception thrown up'
+            noExceptionThrown()
+        and: 'the exception message is logged'
+            def logs = loggingListAppender.list.toString()
+            assert logs.contains('Creating new anchor failed as anchor already exists')
+    }
+
+    def 'Create anchor with any other exception.'() {
+        given: 'the admin service throws a exception'
+            mockCpsAdminService.createAnchor(*_)>>  { throw new RuntimeException('test message') }
+        when: 'attempt to create anchor'
+            objectUnderTest.createAnchor('some dataspace','some schema set','new name')
+        then: 'a startup exception with correct message and details is thrown'
+            def thrown = thrown(NcmpStartUpException)
+            assert thrown.message.contains('Creating anchor failed')
+            assert thrown.details.contains('test message')
+    }
+
+    def 'Create top level node.'() {
+        when: 'top level node is created'
+            objectUnderTest.createTopLevelDataNode('dataspace','anchor','new node')
+        then: 'the correct json is saved using the data service'
+            1 * mockCpsDataService.saveData('dataspace','anchor', '{"new node":{}}',_)
+    }
+
+    def 'Create top level node with already defined exception.'() {
+        given: 'the data service throws an Already Defined exception'
+            mockCpsDataService.saveData(*_) >> { throw AlreadyDefinedException.forDataNodes([], 'some context') }
+        when: 'attempt to create top level node'
+            objectUnderTest.createTopLevelDataNode('dataspace','anchor','new node')
+        then: 'the exception is ignored i.e. no exception thrown up'
+            noExceptionThrown()
+        and: 'the exception message is logged'
+            def logs = loggingListAppender.list.toString()
+            assert logs.contains('failed as data node already exists')
+    }
+
+    def 'Create top level node with any other exception.'() {
+        given: 'the data service throws an exception'
+            mockCpsDataService.saveData(*_) >> { throw new RuntimeException('test message') }
+        when: 'attempt to create top level node'
+            objectUnderTest.createTopLevelDataNode('dataspace','anchor','new node')
+        then: 'a startup exception with correct message and details is thrown'
+            def thrown = thrown(NcmpStartUpException)
+            assert thrown.message.contains('Creating data node failed')
+            assert thrown.details.contains('test message')
+    }
+
+    class TestModelLoader extends AbstractModelLoader {
+
+        TestModelLoader(final CpsAdminService cpsAdminService,
+                        final CpsModuleService cpsModuleService,
+                        final CpsDataService cpsDataService) {
+            super(cpsAdminService, cpsModuleService, cpsDataService)
+            super.maximumAttemptCount = 2
+            super.retryTimeMs = 1
+        }
+
+        @Override
+        void onboardOrUpgradeModel() { }
+    }
+
+}
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/SubscriptionModelLoaderSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/SubscriptionModelLoaderSpec.groovy
index 23fa357ee..305fe4c06 100644
--- a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/SubscriptionModelLoaderSpec.groovy
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/init/SubscriptionModelLoaderSpec.groovy
@@ -26,12 +26,7 @@ import ch.qos.logback.core.read.ListAppender
 import org.onap.cps.api.CpsAdminService
 import org.onap.cps.api.CpsDataService
 import org.onap.cps.api.CpsModuleService
-import org.onap.cps.ncmp.api.impl.exception.NcmpStartUpException
-import org.onap.cps.spi.exceptions.AlreadyDefinedException
-import org.onap.cps.spi.exceptions.DataValidationException
-import org.onap.cps.spi.exceptions.SchemaSetNotFoundException
 import org.onap.cps.spi.model.Dataspace
-import org.springframework.boot.SpringApplication
 import org.slf4j.LoggerFactory
 import org.springframework.boot.context.event.ApplicationReadyEvent
 import org.springframework.context.annotation.AnnotationConfigApplicationContext
@@ -44,18 +39,14 @@ class SubscriptionModelLoaderSpec extends Specification {
     def mockCpsDataService = Mock(CpsDataService)
     def objectUnderTest = new SubscriptionModelLoader(mockCpsAdminService, mockCpsModuleService, mockCpsDataService)
 
-    def sampleYangContentMap = ['subscription.yang':'module subscription { *sample content* }']
-
     def applicationContext = new AnnotationConfigApplicationContext()
 
-    def applicationReadyEvent = new ApplicationReadyEvent(new SpringApplication(), null, applicationContext, null)
-
     def yangResourceToContentMap
-    def logger = (Logger) LoggerFactory.getLogger(objectUnderTest.getClass())
+    def logger = (Logger) LoggerFactory.getLogger(objectUnderTest.class)
     def loggingListAppender
 
     void setup() {
-        yangResourceToContentMap = objectUnderTest.createYangResourceToContentMap()
+        yangResourceToContentMap = objectUnderTest.createYangResourceToContentMap('subscription.yang')
         logger.setLevel(Level.DEBUG)
         loggingListAppender = new ListAppender()
         logger.addAppender(loggingListAppender)
@@ -68,163 +59,31 @@ class SubscriptionModelLoaderSpec extends Specification {
         applicationContext.close()
     }
 
-    def 'Onboard subscription model successfully via application ready event'() {
-        given: 'dataspace is ready for use'
-            mockCpsAdminService.getDataspace('NCMP-Admin') >> new Dataspace('NCMP-Admin')
-        and:'model loader is enabled'
+    def 'Onboard subscription model via application ready event.'() {
+        given:'model loader is enabled'
             objectUnderTest.subscriptionModelLoaderEnabled = true
-        and: 'maximum attempt count is set'
-            objectUnderTest.maximumAttemptCount = 20
-        and: 'retry time is set'
-            objectUnderTest.retryTimeMs = 100
+        and: 'dataspace is ready for use'
+            mockCpsAdminService.getDataspace('NCMP-Admin') >> new Dataspace('')
         when: 'the application is ready'
-            objectUnderTest.onApplicationEvent(applicationReadyEvent)
+            objectUnderTest.onApplicationEvent(Mock(ApplicationReadyEvent))
         then: 'the module service to create schema set is called once'
-            1 * mockCpsModuleService.createSchemaSet('NCMP-Admin', 'subscriptions',sampleYangContentMap)
+            1 * mockCpsModuleService.createSchemaSet('NCMP-Admin', 'subscriptions', yangResourceToContentMap)
         and: 'the admin service to create an anchor set is called once'
             1 * mockCpsAdminService.createAnchor('NCMP-Admin', 'subscriptions', 'AVC-Subscriptions')
         and: 'the data service to create a top level datanode is called once'
             1 * mockCpsDataService.saveData('NCMP-Admin', 'AVC-Subscriptions', '{"subscription-registry":{}}', _)
     }
 
-    def 'No subscription model onboarding when subscription model loader is disabled' () {
-        when: 'model loader is disabled'
+    def 'Subscription model loader disabled.' () {
+        given: 'model loader is disabled'
             objectUnderTest.subscriptionModelLoaderEnabled = false
-        and: 'application is ready'
-            objectUnderTest.onApplicationEvent(applicationReadyEvent)
-        and: 'dataspace is ready for use'
-            mockCpsAdminService.getDataspace('NCMP-Admin') >> new Dataspace('NCMP-Admin')
-        then: 'the module service to create schema set was not called'
-            0 * mockCpsModuleService.createSchemaSet(*_)
-        and: 'the admin service to create an anchor set was not called'
-            0 * mockCpsAdminService.createAnchor(*_)
-        and: 'the data service to create a top level datanode was not called'
-            0 * mockCpsDataService.saveData(*_)
-    }
-
-    def 'Onboard subscription model fails as NCMP dataspace does not exist' () {
-        given: 'model loader is enabled'
-            objectUnderTest.subscriptionModelLoaderEnabled = true
-        and: 'maximum attempt count is set'
-            objectUnderTest.maximumAttemptCount = 20
-        and: 'retry time is set'
-            objectUnderTest.retryTimeMs = 100
-        when: 'the application is ready'
-            objectUnderTest.onApplicationEvent(applicationReadyEvent)
-        then: 'the module service to create schema set was not called'
-            0 * mockCpsModuleService.createSchemaSet(*_)
-        and: 'the admin service to create an anchor set was not called'
-            0 * mockCpsAdminService.createAnchor(*_)
-        and: 'the data service to create a top level datanode was not called'
-            0 * mockCpsDataService.saveData(*_)
-        and: 'the log message contains the correct exception message'
-            def logs = loggingListAppender.list.toString()
-            assert logs.contains("Retrieval of NCMP dataspace fails")
-    }
-
-
-    def 'Exception occurred while schema set creation' () {
-        given: 'creating a schema set throws an exception'
-            mockCpsModuleService.createSchemaSet(*_) >>  { throw new DataValidationException(*_) }
-        and: 'model loader is enabled'
-            objectUnderTest.subscriptionModelLoaderEnabled = true
-        and: 'dataspace is ready for use'
-            mockCpsAdminService.getDataspace('NCMP-Admin') >> new Dataspace('NCMP-Admin')
         when: 'application is ready'
-            objectUnderTest.onApplicationEvent(applicationReadyEvent)
-        then: 'the admin service to create an anchor set was not called'
-            0 * mockCpsAdminService.createAnchor(*_)
-        and: 'the data service to create a top level datanode was not called'
-            0 * mockCpsDataService.saveData(*_)
-    }
-
-    def 'Create schema set from model file'() {
-        when: 'the method to create schema set is called with the following parameters'
-            objectUnderTest.createSchemaSet("myDataspace", "mySchemaSet", yangResourceToContentMap)
-        then: 'yang resource to content map is as expected'
-            assert sampleYangContentMap == yangResourceToContentMap
-        and: 'the module service to create schema set is called once with the correct map'
-            1 * mockCpsModuleService.createSchemaSet(_, _, yangResourceToContentMap)
-    }
-
-    def 'Create schema set fails due to AlreadyDefined exception'() {
-        given: 'creating a schema set throws an exception as it already exists'
-            mockCpsModuleService.createSchemaSet('NCMP-Admin', 'subscriptions', yangResourceToContentMap) >>
-                    { throw AlreadyDefinedException.forSchemaSet('subscriptions', "sampleContextName", null) }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'the admin service to create an anchor set is then called once'
-            1 * mockCpsAdminService.createAnchor('NCMP-Admin', 'subscriptions', 'AVC-Subscriptions')
-    }
-
-    def 'Create schema set fails due to any other exception'() {
-        given: 'creating a schema set throws an exception'
-            mockCpsModuleService.createSchemaSet(*_) >> { throw new NcmpStartUpException("Creating schema set failed", "") }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'the log message contains the correct exception message'
-            def debugMessage = loggingListAppender.list[0].toString()
-            assert debugMessage.contains("Creating schema set failed")
-        and: 'exception is thrown'
-            thrown(NcmpStartUpException)
-    }
-
-    def 'Create anchor fails due to AlreadyDefined exception'() {
-        given: 'creating anchor throws an exception as it already exists'
-            mockCpsAdminService.createAnchor(*_) >>
-                    { throw AlreadyDefinedException.forSchemaSet('subscriptions', "sampleContextName", null) }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'no exception thrown'
-            noExceptionThrown()
-        and: 'the log message contains the correct exception message'
-            def infoMessage = loggingListAppender.list[0].toString()
-            assert infoMessage.contains("already exists")
-    }
-
-    def 'Create anchor fails due to any other exception'() {
-        given: 'creating an anchor failed'
-            mockCpsAdminService.createAnchor(*_) >>
-                    { throw new SchemaSetNotFoundException('NCMP-Admin', 'subscriptions') }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'the log message contains the correct exception message'
-            def debugMessage = loggingListAppender.list[0].toString()
-            assert debugMessage.contains("Schema Set not found")
-        and: 'exception is thrown'
-            thrown(NcmpStartUpException)
-    }
-
-    def 'Create top level node fails due to an AlreadyDefined exception'() {
-        given: 'the saving of the node data will throw an Already Defined exception'
-            mockCpsDataService.saveData(*_) >>
-                    { throw AlreadyDefinedException.forDataNodes(['/xpath'], "sampleContextName") }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'no exception thrown'
-            noExceptionThrown()
-        and: 'the log message contains the correct exception message'
-            def infoMessage = loggingListAppender.list[0].toString()
-            assert infoMessage.contains("already exists")
-    }
-
-    def 'Create top level node fails due to any other exception'() {
-        given: 'the saving of the node data will throw an exception'
-            mockCpsDataService.saveData(*_) >>
-                { throw new DataValidationException("Invalid JSON", "JSON Data is invalid") }
-        when: 'the method to onboard model is called'
-            objectUnderTest.onboardSubscriptionModel(yangResourceToContentMap)
-        then: 'the log message contains the correct exception message'
-            def debugMessage = loggingListAppender.list[0].toString()
-            assert debugMessage.contains("Creating data node for subscription model failed: Invalid JSON")
-        and: 'exception is thrown'
-            thrown(NcmpStartUpException)
+            objectUnderTest.onApplicationEvent(Mock(ApplicationReadyEvent))
+        then: 'no interaction with admin service'
+            0 * mockCpsAdminService.getDataspace(_)
+        then: 'a message is logged that the function is disabled'
+            def logs = loggingListAppender.list.toString()
+            assert logs.contains('Subscription Model Loader is disabled')
     }
 
-    def 'Get file content as string'() {
-        when: 'the method to get yang content is called'
-            objectUnderTest.getFileContentAsString('NonExistingFile')
-        then: 'exception is thrown'
-            thrown(NcmpStartUpException)
-    }
 }
diff --git a/cps-ncmp-service/src/test/resources/model/subscription.yang b/cps-ncmp-service/src/test/resources/model/subscription.yang
deleted file mode 100644
index a575857ab..000000000
--- a/cps-ncmp-service/src/test/resources/model/subscription.yang
+++ /dev/null
@@ -1 +0,0 @@
-module subscription { *sample content* }
\ No newline at end of file