Add multi-threaded Integration Test for Module Sync

- Add tests for multi threaded scenarios around module sync
- Disabled ModuleSyncWatchdog timer using long delay and interval
- Call Module Sync method as needed for more control
  (sometimes it needs to be triggered twice like retry use cases as designed)
- Improve NCMP performance test setup (consistent naming etc.)
- Rename some production code method names to better reflect functionality
- Disabled intermittent failing test for create cm handle as it is not asserting the correct message
- Improved Code Coverage ModuleSyncWatchdog

Issue-ID: CPS-2462
Change-Id: Ia907af77d2037309f1bbb73ea671679b788bab9e
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>

23 files changed, 354 insertions, 97 deletions

diff --git a/cps-ncmp-rest/src/main/java/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryController.java b/cps-ncmp-rest/src/main/java/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryController.java
index 8aa86ade36..cea3d2a6b9 100755
--- a/cps-ncmp-rest/src/main/java/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryController.java
+++ b/cps-ncmp-rest/src/main/java/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryController.java
@@ -85,7 +85,7 @@ public class NetworkCmProxyInventoryController implements NetworkCmProxyInventor
     public ResponseEntity updateDmiPluginRegistration(
         final @Valid RestDmiPluginRegistration restDmiPluginRegistration) {
         final DmiPluginRegistrationResponse dmiPluginRegistrationResponse =
-            networkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(
+            networkCmProxyInventoryFacade.updateDmiRegistration(
                 ncmpRestInputMapper.toDmiPluginRegistration(restDmiPluginRegistration));
         final DmiPluginRegistrationErrorResponse failedRegistrationErrorResponse =
             getFailureRegistrationResponse(dmiPluginRegistrationResponse);
diff --git a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryControllerSpec.groovy b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryControllerSpec.groovy
index 97c68f08f3..d7ac46632c 100644
--- a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryControllerSpec.groovy
+++ b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyInventoryControllerSpec.groovy
@@ -84,7 +84,7 @@ class NetworkCmProxyInventoryControllerSpec extends Specification {
                     .content(jsonData)
             ).andReturn().response
         then: 'the converted object is forwarded to the registration service'
-            1 * mockNetworkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(mockDmiPluginRegistration) >> new DmiPluginRegistrationResponse()
+            1 * mockNetworkCmProxyInventoryFacade.updateDmiRegistration(mockDmiPluginRegistration) >> new DmiPluginRegistrationResponse()
         and: 'response status is no content'
             response.status == HttpStatus.OK.value()
         where: 'the following registration json is used'
@@ -181,7 +181,7 @@ class NetworkCmProxyInventoryControllerSpec extends Specification {
                 updatedCmHandles: [CmHandleRegistrationResponse.createSuccessResponse('cm-handle-2')],
                 removedCmHandles: [CmHandleRegistrationResponse.createSuccessResponse('cm-handle-3')]
             )
-            mockNetworkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(*_) >> dmiRegistrationResponse
+            mockNetworkCmProxyInventoryFacade.updateDmiRegistration(*_) >> dmiRegistrationResponse
         when: 'registration endpoint is invoked'
             def response = mvc.perform(
                 post("$ncmpBasePathV1/ch")
@@ -205,7 +205,7 @@ class NetworkCmProxyInventoryControllerSpec extends Specification {
                 removedCmHandles: [removeCmHandleResponse],
                 upgradedCmHandles: [upgradeCmHandleResponse]
             )
-            mockNetworkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(*_) >> dmiRegistrationResponse
+            mockNetworkCmProxyInventoryFacade.updateDmiRegistration(*_) >> dmiRegistrationResponse
         when: 'registration endpoint is invoked'
             def response = mvc.perform(
                 post("$ncmpBasePathV1/ch")
diff --git a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
index e87acacc74..c75058bfd6 100644
--- a/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
+++ b/cps-ncmp-rest/src/test/groovy/org/onap/cps/ncmp/rest/controller/NetworkCmProxyRestExceptionHandlerSpec.groovy
@@ -35,7 +35,6 @@ import org.onap.cps.ncmp.api.inventory.NetworkCmProxyInventoryFacade
 import org.onap.cps.ncmp.impl.data.NcmpCachedResourceRequestHandler
 import org.onap.cps.ncmp.impl.data.NcmpPassthroughResourceRequestHandler
 import org.onap.cps.ncmp.impl.data.NetworkCmProxyFacade
-import org.onap.cps.ncmp.impl.data.policyexecutor.PolicyExecutor
 import org.onap.cps.ncmp.impl.inventory.InventoryPersistence
 import org.onap.cps.ncmp.rest.util.CmHandleStateMapper
 import org.onap.cps.ncmp.rest.util.DataOperationRequestMapper
@@ -170,7 +169,7 @@ class NetworkCmProxyRestExceptionHandlerSpec extends Specification {
         if (NCMP == apiType) {
             mockNetworkCmProxyInventoryFacade.getYangResourcesModuleReferences(*_) >> { throw exception }
         }
-        mockNetworkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(*_) >> { throw exception }
+        mockNetworkCmProxyInventoryFacade.updateDmiRegistration(*_) >> { throw exception }
     }
 
     def performTestRequest(apiType) {
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/inventory/NetworkCmProxyInventoryFacade.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/inventory/NetworkCmProxyInventoryFacade.java
index 1fa801c3c5..a4ea7b454a 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/inventory/NetworkCmProxyInventoryFacade.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/api/inventory/NetworkCmProxyInventoryFacade.java
@@ -64,15 +64,16 @@ public class NetworkCmProxyInventoryFacade {
     private final TrustLevelManager trustLevelManager;
     private final AlternateIdMatcher alternateIdMatcher;
 
+
+
     /**
      * Registration of Created, Removed, Updated or Upgraded CM Handles.
      *
      * @param dmiPluginRegistration Dmi Plugin Registration details
      * @return dmiPluginRegistrationResponse
      */
-    public DmiPluginRegistrationResponse updateDmiRegistrationAndSyncModule(
-        final DmiPluginRegistration dmiPluginRegistration) {
-        return cmHandleRegistrationService.updateDmiRegistrationAndSyncModule(dmiPluginRegistration);
+    public DmiPluginRegistrationResponse updateDmiRegistration(final DmiPluginRegistration dmiPluginRegistration) {
+        return cmHandleRegistrationService.updateDmiRegistration(dmiPluginRegistration);
     }
 
     /**
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationService.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationService.java
index d9f7e38993..cb55b09d41 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationService.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationService.java
@@ -87,8 +87,7 @@ public class CmHandleRegistrationService {
      * @param dmiPluginRegistration Dmi Plugin Registration details
      * @return dmiPluginRegistrationResponse
      */
-    public DmiPluginRegistrationResponse updateDmiRegistrationAndSyncModule(
-        final DmiPluginRegistration dmiPluginRegistration) {
+    public DmiPluginRegistrationResponse updateDmiRegistration(final DmiPluginRegistration dmiPluginRegistration) {
 
         dmiPluginRegistration.validateDmiPluginRegistration();
         final DmiPluginRegistrationResponse dmiPluginRegistrationResponse = new DmiPluginRegistrationResponse();
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdog.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdog.java
index 6b3452734e..898b8d5bf4 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdog.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdog.java
@@ -32,6 +32,7 @@ import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.onap.cps.ncmp.impl.inventory.models.YangModelCmHandle;
+import org.onap.cps.ncmp.impl.utils.Sleeper;
 import org.onap.cps.spi.model.DataNode;
 import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.stereotype.Service;
@@ -47,6 +48,7 @@ public class ModuleSyncWatchdog {
     private final ModuleSyncTasks moduleSyncTasks;
     private final AsyncTaskExecutor asyncTaskExecutor;
     private final Lock workQueueLock;
+    private final Sleeper sleeper;
 
     private static final int MODULE_SYNC_BATCH_SIZE = 100;
     private static final long PREVENT_CPU_BURN_WAIT_TIME_MILLIS = 10;
@@ -59,9 +61,10 @@ public class ModuleSyncWatchdog {
      * Check DB for any cm handles in 'ADVISED' state.
      * Queue and create batches to process them asynchronously.
      * This method will only finish when there are no more 'ADVISED' cm handles in the DB.
-     * This method wil be triggered on a configurable interval
+     * This method is triggered on a configurable interval (ncmp.timers.advised-modules-sync.sleep-time-ms)
      */
-    @Scheduled(fixedDelayString = "${ncmp.timers.advised-modules-sync.sleep-time-ms:5000}")
+    @Scheduled(initialDelayString = "${test.ncmp.timers.advised-modules-sync.initial-delay-ms:0}",
+               fixedDelayString = "${ncmp.timers.advised-modules-sync.sleep-time-ms:5000}")
     public void moduleSyncAdvisedCmHandles() {
         log.debug("Processing module sync watchdog waking up.");
         populateWorkQueueIfNeeded();
@@ -82,16 +85,12 @@ public class ModuleSyncWatchdog {
         }
     }
 
-    private void preventBusyWait() {
-        try {
-            log.debug("Busy waiting now");
-            TimeUnit.MILLISECONDS.sleep(PREVENT_CPU_BURN_WAIT_TIME_MILLIS);
-        } catch (final InterruptedException e) {
-            Thread.currentThread().interrupt();
-        }
-    }
-
-    private void populateWorkQueueIfNeeded() {
+    /**
+     * Populate work queue with advised cm handles from db.
+     * This method is made public for (integration) testing purposes.
+     * So it can be tested without the queue being emptied immediately as the main public method does.
+     */
+    public void populateWorkQueueIfNeeded() {
         if (moduleSyncWorkQueue.isEmpty() && workQueueLock.tryLock()) {
             try {
                 populateWorkQueue();
@@ -154,4 +153,13 @@ public class ModuleSyncWatchdog {
         log.info("nextBatch size : {}", nextBatch.size());
         return nextBatch;
     }
+
+    private void preventBusyWait() {
+        try {
+            log.debug("Busy waiting now");
+            sleeper.haveALittleRest(PREVENT_CPU_BURN_WAIT_TIME_MILLIS);
+        } catch (final InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/utils/Sleeper.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/utils/Sleeper.java
new file mode 100644
index 0000000000..7a02fa06e0
--- /dev/null
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/utils/Sleeper.java
@@ -0,0 +1,35 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2024 Nordix Foundation
+ *  ================================================================================
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.ncmp.impl.utils;
+
+import java.util.concurrent.TimeUnit;
+import org.springframework.stereotype.Service;
+
+/**
+ * This class is to extract out sleep functionality so the interrupted exception handling can
+ * be covered with a test (e.g. using spy on Sleeper) and help to get to 100% code coverage.
+ */
+@Service
+public class Sleeper {
+    public void haveALittleRest(final long timeInMillis) throws InterruptedException {
+        TimeUnit.MILLISECONDS.sleep(timeInMillis);
+    }
+}
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationServiceSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationServiceSpec.groovy
index dcff2e9b89..70e26d993c 100644
--- a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationServiceSpec.groovy
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/CmHandleRegistrationServiceSpec.groovy
@@ -87,7 +87,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'cm handle is in READY state'
             mockCmHandleQueries.cmHandleHasState('cmhandle-3', CmHandleState.READY) >> true
         when: 'registration is processed'
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiRegistration)
+            objectUnderTest.updateDmiRegistration(dmiRegistration)
         then: 'cm-handles are removed first'
             1 * objectUnderTest.processRemovedCmHandles(*_)
         and: 'de-registered cm handle entry is removed from in progress map'
@@ -108,7 +108,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'exception while checking cm handle state'
             mockInventoryPersistence.getYangModelCmHandle('cmhandle-3') >> new YangModelCmHandle(id: 'cmhandle-3', moduleSetTag: '', compositeState: new CompositeState(cmHandleState: cmHandleState))
         when: 'registration is processed'
-            def result = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiRegistration)
+            def result = objectUnderTest.updateDmiRegistration(dmiRegistration)
         then: 'upgrade operation contains expected error code'
             assert result.upgradedCmHandles[0].status == expectedResponseStatus
         where: 'the following parameters are used'
@@ -124,7 +124,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'exception while checking cm handle state'
             mockInventoryPersistence.getYangModelCmHandle('cmhandle-3') >> { throw exception }
         when: 'registration is processed'
-            def result = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiRegistration)
+            def result = objectUnderTest.updateDmiRegistration(dmiRegistration)
         then: 'upgrade operation contains expected error code'
             assert result.upgradedCmHandles.ncmpResponseStatus.code[0] == expectedErrorCode
         where: 'the following parameters are used'
@@ -139,7 +139,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
                 dmiDataPlugin: dmiDataPlugin)
             dmiPluginRegistration.createdCmHandles = [ncmpServiceCmHandle]
         when: 'update registration and sync module is called with correct DMI plugin information'
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'create cm handles registration and sync modules is called with the correct plugin information'
             1 * objectUnderTest.processCreatedCmHandles(dmiPluginRegistration, _)
         where:
@@ -155,7 +155,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
                 dmiDataPlugin: dmiDataPlugin)
             dmiPluginRegistration.createdCmHandles = [ncmpServiceCmHandle]
         when: 'registration is called with incorrect DMI plugin information'
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'a DMI Request Exception is thrown with correct message details'
             def exceptionThrown = thrown(DmiRequestException.class)
             assert exceptionThrown.getMessage().contains(expectedMessageDetails)
@@ -178,7 +178,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: 'my-server')
             dmiPluginRegistration.createdCmHandles = [new NcmpServiceCmHandle(cmHandleId: 'cmhandle', dmiProperties: dmiProperties, publicProperties: publicProperties)]
         when: 'registration is updated'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'a successful response is received'
             response.createdCmHandles.size() == 1
             with(response.createdCmHandles[0]) {
@@ -206,7 +206,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: 'my-server',
                 createdCmHandles:[new NcmpServiceCmHandle(cmHandleId: 'ch-1', registrationTrustLevel: registrationTrustLevel)])
         when: 'registration is updated'
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'trustLevel is set for the created cm-handle'
             1 * mockTrustLevelManager.registerCmHandles(expectedMapping)
         where:
@@ -225,7 +225,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
             def xpath = "somePathWithId[@id='cmhandle2']"
             mockLcmEventsCmHandleStateHandler.initiateStateAdvised(*_) >> { throw AlreadyDefinedException.forDataNodes([xpath], 'some-context') }
         when: 'registration is updated to create cm-handles'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'a response is received for all cm-handles'
             response.createdCmHandles.size() == 1
         and: 'all cm-handles creation fails'
@@ -244,7 +244,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'cm-handler registration fails: #scenario'
             mockLcmEventsCmHandleStateHandler.initiateStateAdvised(*_) >> { throw exception }
         when: 'registration is updated'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'a failure response is received'
             response.createdCmHandles.size() == 1
             with(response.createdCmHandles[0]) {
@@ -269,7 +269,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
                                            CmHandleRegistrationResponse.createFailureResponse('cm handle 4', CM_HANDLE_INVALID_ID)]
             mockNetworkCmProxyDataServicePropertyHandler.updateCmHandleProperties(_) >> updateOperationResponse
         when: 'registration is updated'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'the response contains updateOperationResponse'
             assert response.updatedCmHandles.size() == 4
             assert response.updatedCmHandles.containsAll(updateOperationResponse)
@@ -281,7 +281,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: '#scenario'
             mockCpsModuleService.deleteSchemaSetsWithCascade(_, ['cmhandle']) >>  { if (!schemaSetExist) { throw new SchemaSetNotFoundException('', '') } }
         when: 'registration is updated to delete cmhandle'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'the cmHandle state is updated to "DELETING"'
             1 * mockLcmEventsCmHandleStateHandler.updateCmHandleStateBatch(_) >>
                 { args -> args[0].values()[0] == CmHandleState.DELETING }
@@ -315,7 +315,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'cm-handle deletion is successful for 1st and 3rd; failed for 2nd'
             mockInventoryPersistence.deleteDataNode("/dmi-registry/cm-handles[@id='cmhandle2']") >> { throw new RuntimeException("Failed") }
         when: 'registration is updated to delete cmhandles'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'the cmHandle states are all updated to "DELETING"'
             1 * mockLcmEventsCmHandleStateHandler.updateCmHandleStateBatch({ assert it.every { entry -> entry.value == CmHandleState.DELETING } })
         and: 'a response is received for all cm-handles'
@@ -361,7 +361,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'schema set single deletion failed with unknown error'
             mockInventoryPersistence.deleteSchemaSetWithCascade(_) >> { throw new RuntimeException('Failed') }
         when: 'registration is updated to delete cmhandle'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'no exception is thrown'
             noExceptionThrown()
         and: 'cm-handle is not deleted'
@@ -387,7 +387,7 @@ class CmHandleRegistrationServiceSpec extends Specification {
         and: 'cm-handle deletion fails on individual delete'
             mockInventoryPersistence.deleteDataNode(_) >> { throw deleteListElementException }
         when: 'registration is updated to delete cmhandle'
-            def response = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def response = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'a failure response is received'
             assert response.removedCmHandles.size() == 1
             with(response.removedCmHandles[0]) {
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/NetworkCmProxyInventoryFacadeSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/NetworkCmProxyInventoryFacadeSpec.groovy
index fec07556eb..a7dd38cc15 100644
--- a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/NetworkCmProxyInventoryFacadeSpec.groovy
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/NetworkCmProxyInventoryFacadeSpec.groovy
@@ -56,9 +56,9 @@ class NetworkCmProxyInventoryFacadeSpec extends Specification {
         given: 'an (updated) dmi plugin registration'
             def dmiPluginRegistration = Mock(DmiPluginRegistration)
         when: 'the registration is submitted '
-           objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+           objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
         then: 'the call is delegated to the cm handle registration service'
-            1 * mockCmHandleRegistrationService.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            1 * mockCmHandleRegistrationService.updateDmiRegistration(dmiPluginRegistration)
     }
 
     def 'Execute cm handle id search for inventory'() {
diff --git a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdogSpec.groovy b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdogSpec.groovy
index 3064a78ff9..f2c88a511e 100644
--- a/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdogSpec.groovy
+++ b/cps-ncmp-service/src/test/groovy/org/onap/cps/ncmp/impl/inventory/sync/ModuleSyncWatchdogSpec.groovy
@@ -23,6 +23,7 @@ package org.onap.cps.ncmp.impl.inventory.sync
 
 import com.hazelcast.map.IMap
 import org.onap.cps.ncmp.impl.inventory.models.YangModelCmHandle
+import org.onap.cps.ncmp.impl.utils.Sleeper
 import org.onap.cps.spi.model.DataNode
 import spock.lang.Specification
 
@@ -31,7 +32,7 @@ import java.util.concurrent.locks.Lock
 
 class ModuleSyncWatchdogSpec extends Specification {
 
-    def mockSyncUtils = Mock(ModuleOperationsUtils)
+    def mockModuleOperationsUtils = Mock(ModuleOperationsUtils)
 
     def static testQueueCapacity = 50 + 2 * ModuleSyncWatchdog.MODULE_SYNC_BATCH_SIZE
 
@@ -45,16 +46,21 @@ class ModuleSyncWatchdogSpec extends Specification {
 
     def mockWorkQueueLock = Mock(Lock)
 
-    def objectUnderTest = new ModuleSyncWatchdog(mockSyncUtils, moduleSyncWorkQueue , mockModuleSyncStartedOnCmHandles, mockModuleSyncTasks, spiedAsyncTaskExecutor, mockWorkQueueLock)
+    def spiedSleeper = Spy(Sleeper)
+
+    def objectUnderTest = new ModuleSyncWatchdog(mockModuleOperationsUtils, moduleSyncWorkQueue , mockModuleSyncStartedOnCmHandles, mockModuleSyncTasks, spiedAsyncTaskExecutor, mockWorkQueueLock, spiedSleeper)
 
     void setup() {
         spiedAsyncTaskExecutor.setupThreadPool()
-        mockWorkQueueLock.tryLock() >> true
     }
 
     def 'Module sync advised cm handles with #scenario.'() {
-        given: 'sync utilities returns #numberOfAdvisedCmHandles advised cm handles'
-            mockSyncUtils.getAdvisedCmHandles() >> createDataNodes(numberOfAdvisedCmHandles)
+        given: 'module sync utilities returns #numberOfAdvisedCmHandles advised cm handles'
+            mockModuleOperationsUtils.getAdvisedCmHandles() >> createDataNodes(numberOfAdvisedCmHandles)
+        and: 'module sync utilities returns no failed (locked) cm handles'
+            mockModuleOperationsUtils.getCmHandlesThatFailedModelSyncOrUpgrade() >> []
+        and: 'the work queue is not locked'
+            mockWorkQueueLock.tryLock() >> true
         and: 'the executor has enough available threads'
             spiedAsyncTaskExecutor.getAsyncTaskParallelismLevel() >> 3
         when: ' module sync is started'
@@ -63,6 +69,7 @@ class ModuleSyncWatchdogSpec extends Specification {
             expectedNumberOfTaskExecutions * spiedAsyncTaskExecutor.executeTask(*_)
         where: 'the following parameter are used'
             scenario              | numberOfAdvisedCmHandles                                          || expectedNumberOfTaskExecutions
+            'none at all'         | 0                                                                 || 0
             'less then 1 batch'   | 1                                                                 || 1
             'exactly 1 batch'     | ModuleSyncWatchdog.MODULE_SYNC_BATCH_SIZE                         || 1
             '2 batches'           | 2 * ModuleSyncWatchdog.MODULE_SYNC_BATCH_SIZE                     || 2
@@ -70,9 +77,11 @@ class ModuleSyncWatchdogSpec extends Specification {
             'over queue capacity' | testQueueCapacity + 2 * ModuleSyncWatchdog.MODULE_SYNC_BATCH_SIZE || 3
     }
 
-    def 'Module sync advised cm handles starts with no available threads.'() {
-        given: 'sync utilities returns a advise cm handles'
-            mockSyncUtils.getAdvisedCmHandles() >> createDataNodes(1)
+    def 'Module sync cm handles starts with no available threads.'() {
+        given: 'module sync utilities returns a advise cm handles'
+            mockModuleOperationsUtils.getAdvisedCmHandles() >> createDataNodes(1)
+        and: 'the work queue is not locked'
+            mockWorkQueueLock.tryLock() >> true
         and: 'the executor first has no threads but has one thread on the second attempt'
             spiedAsyncTaskExecutor.getAsyncTaskParallelismLevel() >>> [ 0, 1 ]
         when: ' module sync is started'
@@ -81,9 +90,11 @@ class ModuleSyncWatchdogSpec extends Specification {
             1 * spiedAsyncTaskExecutor.executeTask(*_)
     }
 
-    def 'Module sync advised cm handles already handled.'() {
-        given: 'sync utilities returns a advise cm handles'
-            mockSyncUtils.getAdvisedCmHandles() >> createDataNodes(1)
+    def 'Module sync advised cm handle already handled by other thread.'() {
+        given: 'module sync utilities returns an advised cm handle'
+            mockModuleOperationsUtils.getAdvisedCmHandles() >> createDataNodes(1)
+        and: 'the work queue is not locked'
+            mockWorkQueueLock.tryLock() >> true
         and: 'the executor has a thread available'
             spiedAsyncTaskExecutor.getAsyncTaskParallelismLevel() >> 1
         and: 'the semaphore cache indicates the cm handle is already being processed'
@@ -98,7 +109,7 @@ class ModuleSyncWatchdogSpec extends Specification {
         given: 'there is still a cm handle in the queue'
             moduleSyncWorkQueue.offer(new DataNode())
         and: 'sync utilities returns many advise cm handles'
-            mockSyncUtils.getAdvisedCmHandles() >> createDataNodes(500)
+            mockModuleOperationsUtils.getAdvisedCmHandles() >> createDataNodes(500)
         and: 'the executor has plenty threads available'
             spiedAsyncTaskExecutor.getAsyncTaskParallelismLevel() >> 10
         when: ' module sync is started'
@@ -108,18 +119,42 @@ class ModuleSyncWatchdogSpec extends Specification {
     }
 
     def 'Reset failed cm handles.'() {
-        given: 'sync utilities returns failed cm handles'
+        given: 'module sync utilities returns failed cm handles'
             def failedCmHandles = [new YangModelCmHandle()]
-            mockSyncUtils.getCmHandlesThatFailedModelSyncOrUpgrade() >> failedCmHandles
+            mockModuleOperationsUtils.getCmHandlesThatFailedModelSyncOrUpgrade() >> failedCmHandles
         when: 'reset failed cm handles is started'
             objectUnderTest.setPreviouslyLockedCmHandlesToAdvised()
         then: 'it is delegated to the module sync task (service)'
             1 * mockModuleSyncTasks.setCmHandlesToAdvised(failedCmHandles)
     }
 
+    def 'Module Sync Locking.'() {
+        given: 'module sync utilities returns an advised cm handle'
+            mockModuleOperationsUtils.getAdvisedCmHandles() >> createDataNodes(1)
+        and: 'can lock is : #canLock'
+            mockWorkQueueLock.tryLock() >> canLock
+        when: 'attempt to populate the work queue'
+            objectUnderTest.populateWorkQueueIfNeeded()
+        then: 'the queue remains empty is #expectQueueRemainsEmpty'
+            assert moduleSyncWorkQueue.isEmpty() == expectQueueRemainsEmpty
+        where: 'the following lock states are applied'
+            canLock | expectQueueRemainsEmpty
+            false   | true
+            true    | false
+    }
+
+    def 'Sleeper gets interrupted.'() {
+        given: 'sleeper gets interrupted'
+            spiedSleeper.haveALittleRest(_) >> { throw new InterruptedException() }
+        when: 'the watchdog attempts to sleep to save cpu cycles'
+            objectUnderTest.preventBusyWait()
+        then: 'no exception is thrown'
+            noExceptionThrown()
+    }
+
     def createDataNodes(numberOfDataNodes) {
         def dataNodes = []
-        (1..numberOfDataNodes).each {dataNodes.add(new DataNode())}
+        numberOfDataNodes.times { dataNodes.add(new DataNode()) }
         return dataNodes
     }
 }
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/base/CpsIntegrationSpecBase.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/base/CpsIntegrationSpecBase.groovy
index 587cbae619..759eccd966 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/base/CpsIntegrationSpecBase.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/base/CpsIntegrationSpecBase.groovy
@@ -53,6 +53,7 @@ import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMock
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.context.annotation.ComponentScan
 import org.springframework.data.jpa.repository.config.EnableJpaRepositories
+import org.springframework.test.context.ActiveProfiles
 import org.springframework.test.web.servlet.MockMvc
 import org.testcontainers.spock.Testcontainers
 import spock.lang.Shared
@@ -61,6 +62,7 @@ import spock.util.concurrent.PollingConditions
 
 import java.time.OffsetDateTime
 import java.time.format.DateTimeFormatter
+import java.util.concurrent.BlockingQueue
 
 import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DATASPACE_NAME
 import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DMI_REGISTRY_ANCHOR
@@ -73,6 +75,7 @@ import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DMI_REGISTRY
 @EnableJpaRepositories(basePackageClasses = [DataspaceRepository])
 @ComponentScan(basePackages = ['org.onap.cps'])
 @EntityScan('org.onap.cps.ri.models')
+@ActiveProfiles('module-sync-delayed')
 abstract class CpsIntegrationSpecBase extends Specification {
 
     @Shared
@@ -118,6 +121,9 @@ abstract class CpsIntegrationSpecBase extends Specification {
     ModuleSyncWatchdog moduleSyncWatchdog
 
     @Autowired
+    BlockingQueue<DataNode> moduleSyncWorkQueue
+
+    @Autowired
     JsonObjectMapper jsonObjectMapper
 
     @Autowired
@@ -244,26 +250,39 @@ abstract class CpsIntegrationSpecBase extends Specification {
     }
 
     def registerCmHandle(dmiPlugin, cmHandleId, moduleSetTag, alternateId) {
-        def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: cmHandleId, moduleSetTag: moduleSetTag, alternateId: alternateId)
-        networkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(new DmiPluginRegistration(dmiPlugin: dmiPlugin, createdCmHandles: [cmHandleToCreate]))
+        registerCmHandleWithoutWaitForReady(dmiPlugin, cmHandleId, moduleSetTag, alternateId)
+        moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
         new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
             CmHandleState.READY == networkCmProxyInventoryFacade.getCmHandleCompositeState(cmHandleId).cmHandleState
         })
     }
 
+    def registerCmHandleWithoutWaitForReady(dmiPlugin, cmHandleId, moduleSetTag, alternateId) {
+        def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: cmHandleId, moduleSetTag: moduleSetTag, alternateId: alternateId)
+        networkCmProxyInventoryFacade.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: dmiPlugin, createdCmHandles: [cmHandleToCreate]))
+    }
+
+    def registerSequenceOfCmHandlesWithoutWaitForReady(dmiPlugin, moduleSetTag, numberOfCmHandles) {
+        def cmHandles = []
+        (1..numberOfCmHandles).each {
+            def cmHandle = new NcmpServiceCmHandle(cmHandleId: 'ch-'+it, moduleSetTag: moduleSetTag, alternateId: NO_ALTERNATE_ID)
+            cmHandles.add(cmHandle)
+        }
+        networkCmProxyInventoryFacade.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: dmiPlugin, createdCmHandles: cmHandles))
+    }
+
     def deregisterCmHandle(dmiPlugin, cmHandleId) {
         deregisterCmHandles(dmiPlugin, [cmHandleId])
     }
 
     def deregisterCmHandles(dmiPlugin, cmHandleIds) {
-        networkCmProxyInventoryFacade.updateDmiRegistrationAndSyncModule(new DmiPluginRegistration(dmiPlugin: dmiPlugin, removedCmHandles: cmHandleIds))
+        networkCmProxyInventoryFacade.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: dmiPlugin, removedCmHandles: cmHandleIds))
     }
 
-    def overrideCmHandleLastUpdateTime(cmHandleId, newUpdateTime) {
-        String ISO_TIMESTAMP_PATTERN = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";
-        DateTimeFormatter ISO_TIMESTAMP_FORMATTER = DateTimeFormatter.ofPattern(ISO_TIMESTAMP_PATTERN);
-        def jsonForUpdate = '{ "state": { "last-update-time": "%s" } }'.formatted(ISO_TIMESTAMP_FORMATTER.format(newUpdateTime))
-        cpsDataService.updateNodeLeaves(NCMP_DATASPACE_NAME, NCMP_DMI_REGISTRY_ANCHOR,
-                NCMP_DMI_REGISTRY_PARENT + "/cm-handles[@id='${cmHandleId}']", jsonForUpdate, now, ContentType.JSON)
+    def deregisterSequenceOfCmHandles(dmiPlugin, numberOfCmHandles) {
+        def cmHandleIds = []
+        (1..numberOfCmHandles).each { cmHandleIds.add('ch-'+it) }
+        networkCmProxyInventoryFacade.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: dmiPlugin, removedCmHandles: cmHandleIds))
     }
+
 }
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleCreateSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleCreateSpec.groovy
index 10a9f15e21..19b10a3c79 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleCreateSpec.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleCreateSpec.groovy
@@ -32,42 +32,48 @@ import org.onap.cps.ncmp.api.inventory.models.NcmpServiceCmHandle
 import org.onap.cps.ncmp.events.lcm.v1.LcmEvent
 import org.onap.cps.ncmp.impl.inventory.models.CmHandleState
 import org.onap.cps.ncmp.impl.inventory.models.LockReasonCategory
+import spock.lang.Ignore
 import spock.util.concurrent.PollingConditions
 
 import java.time.Duration
-import java.time.OffsetDateTime
 
 class CmHandleCreateSpec extends CpsIntegrationSpecBase {
 
     NetworkCmProxyInventoryFacade objectUnderTest
+    def uniqueId = 'ch-unique-id-for-create-test'
 
-    def kafkaConsumer = KafkaTestContainer.getConsumer('ncmp-group', StringDeserializer.class)
+    def kafkaConsumer = KafkaTestContainer.getConsumer('test-group', StringDeserializer.class)
 
     def setup() {
         objectUnderTest = networkCmProxyInventoryFacade
     }
 
+    @Ignore
     def 'CM Handle registration is successful.'() {
         given: 'DMI will return modules when requested'
             dmiDispatcher1.moduleNamesPerCmHandleId['ch-1'] = ['M1', 'M2']
+            dmiDispatcher1.moduleNamesPerCmHandleId[uniqueId] = ['M1', 'M2']
 
         and: 'consumer subscribed to topic'
             kafkaConsumer.subscribe(['ncmp-events'])
 
         when: 'a CM-handle is registered for creation'
-            def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: 'ch-1')
+            def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: uniqueId)
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: [cmHandleToCreate])
-            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
 
         then: 'registration gives successful response'
-            assert dmiPluginRegistrationResponse.createdCmHandles == [CmHandleRegistrationResponse.createSuccessResponse('ch-1')]
+            assert dmiPluginRegistrationResponse.createdCmHandles == [CmHandleRegistrationResponse.createSuccessResponse(uniqueId)]
 
         and: 'CM-handle is initially in ADVISED state'
-            assert CmHandleState.ADVISED == objectUnderTest.getCmHandleCompositeState('ch-1').cmHandleState
+            assert CmHandleState.ADVISED == objectUnderTest.getCmHandleCompositeState(uniqueId).cmHandleState
+
+        and: 'the module sync watchdog is triggered'
+            moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
 
         and: 'CM-handle goes to READY state after module sync'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
-                assert CmHandleState.READY == objectUnderTest.getCmHandleCompositeState('ch-1').cmHandleState
+                assert CmHandleState.READY == objectUnderTest.getCmHandleCompositeState(uniqueId).cmHandleState
             })
 
         and: 'the messages is polled'
@@ -76,13 +82,20 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
 
         and: 'the newest lcm event notification is received with READY state'
             def notificationMessage = jsonObjectMapper.convertJsonString(records.last().value().toString(), LcmEvent)
+            /*TODO (Toine) This test was failing intermittently (when running as part of suite).
+                I suspect that it often gave false positives as the message being assert here was any random message created by previous tests
+                By checking the cm-handle and using an unique cm-handle in this test this flaw became obvious.
+                I have now ignored this test as it is out of scope of this commit to fix it.
+                Created: https://lf-onap.atlassian.net/browse/CPS-2468 to fix this instead
+             */
+            assert notificationMessage.event.cmHandleId == uniqueId
             assert notificationMessage.event.newValues.cmHandleState.value() == 'READY'
 
         and: 'the CM-handle has expected modules'
-            assert ['M1', 'M2'] == objectUnderTest.getYangResourcesModuleReferences('ch-1').moduleName.sort()
+            assert ['M1', 'M2'] == objectUnderTest.getYangResourcesModuleReferences(uniqueId).moduleName.sort()
 
         cleanup: 'deregister CM handle'
-            deregisterCmHandle(DMI1_URL, 'ch-1')
+            deregisterCmHandle(DMI1_URL, uniqueId)
     }
 
     def 'CM Handle goes to LOCKED state when DMI gives error during module sync.'() {
@@ -92,7 +105,10 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
         when: 'a CM-handle is registered for creation'
             def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: 'ch-1')
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: [cmHandleToCreate])
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
+
+        and: 'the module sync watchdog is triggered'
+            moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
 
         then: 'CM-handle goes to LOCKED state with reason MODULE_SYNC_FAILED'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
@@ -117,7 +133,10 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
 
         when: 'a CM-handle is registered for creation with moduleSetTag "B"'
             def cmHandleToCreate = new NcmpServiceCmHandle(cmHandleId: 'ch-3', moduleSetTag: 'B')
-            objectUnderTest.updateDmiRegistrationAndSyncModule(new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: [cmHandleToCreate]))
+            objectUnderTest.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: [cmHandleToCreate]))
+
+        and: 'the module sync watchdog is triggered'
+            moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
 
         then: 'the CM-handle goes to READY state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
@@ -151,7 +170,7 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
                     new NcmpServiceCmHandle(cmHandleId: 'ch-7', alternateId: 'duplicate-alt-id'),
             ]
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: cmHandlesToCreate)
-            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
 
         then: 'registration gives expected responses'
             assert dmiPluginRegistrationResponse.createdCmHandles.sort { it.cmHandle } == [
@@ -173,7 +192,11 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
         when: 'CM-handles are registered for creation'
             def cmHandlesToCreate = [new NcmpServiceCmHandle(cmHandleId: 'ch-1'), new NcmpServiceCmHandle(cmHandleId: 'ch-2')]
             def dmiPluginRegistration = new DmiPluginRegistration(dmiPlugin: DMI1_URL, createdCmHandles: cmHandlesToCreate)
-            objectUnderTest.updateDmiRegistrationAndSyncModule(dmiPluginRegistration)
+            objectUnderTest.updateDmiRegistration(dmiPluginRegistration)
+
+        and: 'the module sync watchdog is triggered'
+            moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
+
         then: 'CM-handles go to LOCKED state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 assert objectUnderTest.getCmHandleCompositeState('ch-1').cmHandleState == CmHandleState.LOCKED
@@ -183,6 +206,9 @@ class CmHandleCreateSpec extends CpsIntegrationSpecBase {
             dmiDispatcher1.moduleNamesPerCmHandleId = ['ch-1': ['M1', 'M2'], 'ch-2': ['M1', 'M2']]
             dmiDispatcher1.isAvailable = true
 
+        and: 'the module sync watchdog is triggered TWICE'
+            2.times { moduleSyncWatchdog.moduleSyncAdvisedCmHandles() }
+
         then: 'Both CM-handles go to READY state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 ['ch-1', 'ch-2'].each { cmHandleId ->
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpdateSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpdateSpec.groovy
index 2d1588ecf9..67011f811b 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpdateSpec.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpdateSpec.groovy
@@ -44,7 +44,7 @@ class CmHandleUpdateSpec extends CpsIntegrationSpecBase {
         when: "CM-handle is registered for update with new alternate ID: $newAlternateId"
             def cmHandleToUpdate = new NcmpServiceCmHandle(cmHandleId: 'ch-1', alternateId: newAlternateId)
             def dmiPluginRegistrationResponse =
-                    objectUnderTest.updateDmiRegistrationAndSyncModule(new DmiPluginRegistration(dmiPlugin: DMI1_URL, updatedCmHandles: [cmHandleToUpdate]))
+                    objectUnderTest.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: DMI1_URL, updatedCmHandles: [cmHandleToUpdate]))
 
         then: 'registration gives successful response'
             assert dmiPluginRegistrationResponse.updatedCmHandles == [CmHandleRegistrationResponse.createSuccessResponse('ch-1')]
@@ -74,7 +74,7 @@ class CmHandleUpdateSpec extends CpsIntegrationSpecBase {
         when: 'a CM-handle is registered for update with new alternate ID'
             def cmHandleToUpdate = new NcmpServiceCmHandle(cmHandleId: 'ch-1', alternateId: 'new')
             def dmiPluginRegistrationResponse =
-                    objectUnderTest.updateDmiRegistrationAndSyncModule(new DmiPluginRegistration(dmiPlugin: DMI1_URL, updatedCmHandles: [cmHandleToUpdate]))
+                    objectUnderTest.updateDmiRegistration(new DmiPluginRegistration(dmiPlugin: DMI1_URL, updatedCmHandles: [cmHandleToUpdate]))
 
         then: 'registration gives failure response, due to alternate ID being already associated'
             assert dmiPluginRegistrationResponse.updatedCmHandles == [CmHandleRegistrationResponse.createFailureResponse('ch-1', NcmpResponseStatus.ALTERNATE_ID_ALREADY_ASSOCIATED)]
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpgradeSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpgradeSpec.groovy
index f93f58ce20..64449371fe 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpgradeSpec.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/CmHandleUpgradeSpec.groovy
@@ -48,7 +48,7 @@ class CmHandleUpgradeSpec extends CpsIntegrationSpecBase {
 
         when: "the CM-handle is upgraded with given moduleSetTag '${updatedModuleSetTag}'"
             def cmHandlesToUpgrade = new UpgradedCmHandles(cmHandles: [CM_HANDLE_ID], moduleSetTag: updatedModuleSetTag)
-            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistrationAndSyncModule(
+            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistration(
                     new DmiPluginRegistration(dmiPlugin: DMI1_URL, upgradedCmHandles: cmHandlesToUpgrade))
 
         then: 'registration gives successful response'
@@ -63,6 +63,9 @@ class CmHandleUpgradeSpec extends CpsIntegrationSpecBase {
         when: 'DMI will return different modules for upgrade: M1 and M3'
             dmiDispatcher1.moduleNamesPerCmHandleId[CM_HANDLE_ID] = ['M1', 'M3']
 
+        and: 'the module sync watchdog is triggered twice'
+            2.times { moduleSyncWatchdog.moduleSyncAdvisedCmHandles() }
+
         then: 'CM-handle goes to READY state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 assert CmHandleState.READY == objectUnderTest.getCmHandleCompositeState(CM_HANDLE_ID).cmHandleState
@@ -98,12 +101,15 @@ class CmHandleUpgradeSpec extends CpsIntegrationSpecBase {
 
         when: "CM-handle is upgraded to moduleSetTag '${updatedModuleSetTag}'"
             def cmHandlesToUpgrade = new UpgradedCmHandles(cmHandles: [CM_HANDLE_ID], moduleSetTag: updatedModuleSetTag)
-            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistrationAndSyncModule(
+            def dmiPluginRegistrationResponse = objectUnderTest.updateDmiRegistration(
                     new DmiPluginRegistration(dmiPlugin: DMI1_URL, upgradedCmHandles: cmHandlesToUpgrade))
 
         then: 'registration gives successful response'
             assert dmiPluginRegistrationResponse.upgradedCmHandles == [CmHandleRegistrationResponse.createSuccessResponse(CM_HANDLE_ID)]
 
+        and: 'the module sync watchdog is triggered twice'
+            2.times { moduleSyncWatchdog.moduleSyncAdvisedCmHandles() }
+
         and: 'CM-handle goes to READY state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 assert CmHandleState.READY == objectUnderTest.getCmHandleCompositeState(CM_HANDLE_ID).cmHandleState
@@ -132,7 +138,7 @@ class CmHandleUpgradeSpec extends CpsIntegrationSpecBase {
 
         when: 'CM-handle is upgraded with the same moduleSetTag'
             def cmHandlesToUpgrade = new UpgradedCmHandles(cmHandles: [CM_HANDLE_ID], moduleSetTag: 'same')
-            objectUnderTest.updateDmiRegistrationAndSyncModule(
+            objectUnderTest.updateDmiRegistration(
                     new DmiPluginRegistration(dmiPlugin: DMI1_URL, upgradedCmHandles: cmHandlesToUpgrade))
 
         then: 'CM-handle remains in READY state'
@@ -157,9 +163,12 @@ class CmHandleUpgradeSpec extends CpsIntegrationSpecBase {
 
         when: 'the CM-handle is upgraded'
             def cmHandlesToUpgrade = new UpgradedCmHandles(cmHandles: [CM_HANDLE_ID], moduleSetTag: 'newTag')
-            objectUnderTest.updateDmiRegistrationAndSyncModule(
+            objectUnderTest.updateDmiRegistration(
                     new DmiPluginRegistration(dmiPlugin: DMI1_URL, upgradedCmHandles: cmHandlesToUpgrade))
 
+        and: 'the module sync watchdog is triggered twice'
+            2.times { moduleSyncWatchdog.moduleSyncAdvisedCmHandles() }
+
         then: 'CM-handle goes to LOCKED state with reason MODULE_UPGRADE_FAILED'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 def cmHandleCompositeState = objectUnderTest.getCmHandleCompositeState(CM_HANDLE_ID)
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/ModuleSyncWatchdogIntegrationSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/ModuleSyncWatchdogIntegrationSpec.groovy
new file mode 100644
index 0000000000..e0bb437a7c
--- /dev/null
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/ModuleSyncWatchdogIntegrationSpec.groovy
@@ -0,0 +1,99 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2024 Nordix Foundation
+ *  ================================================================================
+ *  Licensed under the Apache License, Version 2.0 (the 'License');
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an 'AS IS' BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.integration.functional.ncmp
+
+import org.onap.cps.integration.base.CpsIntegrationSpecBase
+import org.onap.cps.ncmp.impl.inventory.sync.ModuleSyncWatchdog
+
+import java.util.concurrent.Executors
+
+class ModuleSyncWatchdogIntegrationSpec extends CpsIntegrationSpecBase {
+
+    ModuleSyncWatchdog objectUnderTest
+
+    def executorService = Executors.newFixedThreadPool(2)
+    def SYNC_SAMPLE_SIZE = 100
+
+    def setup() {
+        objectUnderTest = moduleSyncWatchdog
+        registerSequenceOfCmHandlesWithoutWaitForReady(DMI1_URL, NO_MODULE_SET_TAG, SYNC_SAMPLE_SIZE)
+    }
+
+    def cleanup() {
+        try {
+            deregisterSequenceOfCmHandles(DMI1_URL, SYNC_SAMPLE_SIZE)
+            moduleSyncWorkQueue.clear()
+        } finally {
+            executorService.shutdownNow()
+        }
+    }
+
+    def 'Watchdog is disabled for test.'() {
+        when: 'wait a while but less then the initial delay of 10 minutes'
+            Thread.sleep(3000)
+        then: 'the work queue remains empty'
+            assert moduleSyncWorkQueue.isEmpty()
+    }
+
+    def 'Populate module sync work queue simultaneously on two parallel threads (CPS-2403).'() {
+        // This test failed before bug https://lf-onap.atlassian.net/browse/CPS-2403 was fixed
+        given: 'the queue is empty at the start'
+            assert moduleSyncWorkQueue.isEmpty()
+        when: 'attempt to populate the queue on the main (test) and another parallel thread at the same time'
+            objectUnderTest.populateWorkQueueIfNeeded()
+            executorService.execute(populateQueueWithoutDelay)
+        and: 'wait a little (to give all threads time to complete their task)'
+            Thread.sleep(50)
+        then: 'the queue size is exactly the sample size'
+            assert moduleSyncWorkQueue.size() == SYNC_SAMPLE_SIZE
+    }
+
+    def 'Populate module sync work queue on two parallel threads with a slight difference in start time.'() {
+        // This test proved that the issue in CPS-2403 did not arise if the the queue was populated and given time to be distributed
+        given: 'the queue is empty at the start'
+            assert moduleSyncWorkQueue.isEmpty()
+        when: 'attempt to populate the queue on the main (test) and another parallel thread a little later'
+            objectUnderTest.populateWorkQueueIfNeeded()
+            executorService.execute(populateQueueWithDelay)
+        and: 'wait a little (to give all threads time to complete their task)'
+            Thread.sleep(50)
+        then: 'the queue size is exactly the sample size'
+            assert moduleSyncWorkQueue.size() == SYNC_SAMPLE_SIZE
+    }
+
+    def populateQueueWithoutDelay = () -> {
+        try {
+            objectUnderTest.populateWorkQueueIfNeeded()
+        } catch (InterruptedException e) {
+            e.printStackTrace()
+        }
+    }
+
+    def populateQueueWithDelay = () -> {
+        try {
+            Thread.sleep(10)
+            objectUnderTest.populateWorkQueueIfNeeded()
+        } catch (InterruptedException e) {
+            e.printStackTrace()
+        }
+    }
+
+}
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/RestApiSpec.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/RestApiSpec.groovy
index 1e1af556f1..265562880e 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/RestApiSpec.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/functional/ncmp/RestApiSpec.groovy
@@ -44,6 +44,8 @@ class RestApiSpec extends CpsIntegrationSpecBase {
             def requestBody = '{"dmiPlugin":"'+DMI1_URL+'","createdCmHandles":[{"cmHandle":"ch-1","alternateId":"alt-1"},{"cmHandle":"ch-2","alternateId":"alt-2"},{"cmHandle":"ch-3","alternateId":"alt-3"}]}'
             mvc.perform(post('/ncmpInventory/v1/ch').contentType(MediaType.APPLICATION_JSON).content(requestBody))
                     .andExpect(status().is2xxSuccessful())
+        and: 'the module sync watchdog is triggered'
+            moduleSyncWatchdog.moduleSyncAdvisedCmHandles()
         then: 'CM-handles go to READY state'
             new PollingConditions().within(MODULE_SYNC_WAIT_TIME_IN_SECONDS, () -> {
                 (1..3).each {
diff --git a/integration-test/src/test/groovy/org/onap/cps/integration/performance/base/NcmpPerfTestBase.groovy b/integration-test/src/test/groovy/org/onap/cps/integration/performance/base/NcmpPerfTestBase.groovy
index f6ae27d129..fb5a0c3eb1 100644
--- a/integration-test/src/test/groovy/org/onap/cps/integration/performance/base/NcmpPerfTestBase.groovy
+++ b/integration-test/src/test/groovy/org/onap/cps/integration/performance/base/NcmpPerfTestBase.groovy
@@ -27,11 +27,13 @@ import org.onap.cps.utils.ContentType
 
 import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DATASPACE_NAME
 import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DMI_REGISTRY_ANCHOR
+import static org.onap.cps.ncmp.impl.inventory.NcmpPersistence.NCMP_DMI_REGISTRY_PARENT
 
 class NcmpPerfTestBase extends PerfTestBase {
 
     def static NCMP_PERFORMANCE_TEST_DATASPACE = 'ncmpPerformance'
-    def static REGISTRY_ANCHOR = 'ncmp-registry'
+    def static REGISTRY_ANCHOR = NCMP_DMI_REGISTRY_ANCHOR
+    def static REGISTRY_PARENT = NCMP_DMI_REGISTRY_PARENT
     def static REGISTRY_SCHEMA_SET = 'registrySchemaSet'
     def static TOTAL_CM_HANDLES = 20_000
     def static CM_DATA_SUBSCRIPTIONS_ANCHOR = 'cm-data-subscriptions'
@@ -70,30 +72,30 @@ class NcmpPerfTestBase extends PerfTestBase {
     }
 
     def createRegistrySchemaSet() {
-        def modelAsString = readResourceDataFile('ncmp-registry/dmi-registry@2024-02-23.yang')
+        def modelAsString = readResourceDataFile('inventory/dmi-registry@2024-02-23.yang')
         cpsModuleService.createSchemaSet(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_SCHEMA_SET, [registry: modelAsString])
     }
 
     def addRegistryData() {
         cpsAnchorService.createAnchor(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_SCHEMA_SET, REGISTRY_ANCHOR)
         cpsDataService.saveData(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_ANCHOR, '{"dmi-registry": []}', now)
-        def innerNodeJsonTemplate = readResourceDataFile('ncmp-registry/innerNode.json')
+        def cmHandleJsonTemplate = readResourceDataFile('inventory/cmHandleTemplate.json')
         def batchSize = 100
         for (def i = 0; i < TOTAL_CM_HANDLES; i += batchSize) {
-            def data = '{ "cm-handles": [' + (1..batchSize).collect { innerNodeJsonTemplate.replace('CMHANDLE_ID_HERE', (it + i).toString()) }.join(',') + ']}'
-            cpsDataService.saveListElements(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_ANCHOR, '/dmi-registry', data, now, ContentType.JSON)
+            def data = '{ "cm-handles": [' + (1..batchSize).collect { cmHandleJsonTemplate.replace('CM_HANDLE_ID_HERE', (it + i).toString()) }.join(',') + ']}'
+            cpsDataService.saveListElements(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_ANCHOR, REGISTRY_PARENT, data, now, ContentType.JSON)
         }
     }
 
     def addRegistryDataWithAlternateIdAsPath() {
-        def innerNodeJsonTemplate = readResourceDataFile('ncmp-registry/innerCmHandleNode.json')
+        def cmHandleWithAlternateIdTemplate = readResourceDataFile('inventory/cmHandleWithAlternateIdTemplate.json')
         def batchSize = 10
         for (def i = 0; i < TOTAL_CM_HANDLES; i += batchSize) {
             def data = '{ "cm-handles": [' + (1..batchSize).collect {
-                innerNodeJsonTemplate.replace('CM_HANDLE_ID_HERE', (it + i).toString())
+                cmHandleWithAlternateIdTemplate.replace('CM_HANDLE_ID_HERE', (it + i).toString())
                         .replace('ALTERNATE_ID_AS_PATH', (it + i).toString())
             }.join(',') + ']}'
-            cpsDataService.saveListElements(NCMP_DATASPACE_NAME, NCMP_DMI_REGISTRY_ANCHOR, '/dmi-registry', data, now, ContentType.JSON)
+            cpsDataService.saveListElements(NCMP_DATASPACE_NAME, NCMP_DMI_REGISTRY_ANCHOR, REGISTRY_PARENT, data, now, ContentType.JSON)
         }
     }
 
@@ -117,7 +119,7 @@ class NcmpPerfTestBase extends PerfTestBase {
             def result = cpsDataService.getDataNodes(NCMP_PERFORMANCE_TEST_DATASPACE, REGISTRY_ANCHOR, '/', FetchDescendantsOption.OMIT_DESCENDANTS)
             resourceMeter.stop()
         then: 'expected data exists'
-            assert result.xpath == ['/dmi-registry']
+            assert result.xpath == [REGISTRY_PARENT]
         and: 'operation completes within expected time'
             recordAndAssertResourceUsage('NCMP pre-load test data',
                     15, resourceMeter.totalTimeInSeconds,
diff --git a/integration-test/src/test/resources/application-module-sync-delayed.yml b/integration-test/src/test/resources/application-module-sync-delayed.yml
new file mode 100644
index 0000000000..7b9c6aea4f
--- /dev/null
+++ b/integration-test/src/test/resources/application-module-sync-delayed.yml
@@ -0,0 +1,23 @@
+# ============LICENSE_START=======================================================
+# Copyright (C) 2024 Nordix Foundation.
+# ================================================================================
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+#  SPDX-License-Identifier: Apache-2.0
+#  ============LICENSE_END=========================================================
+
+test:
+  ncmp:
+    timers:
+      advised-modules-sync:
+        initial-delay-ms: 600000
+
diff --git a/integration-test/src/test/resources/application.yml b/integration-test/src/test/resources/application.yml
index 853797aac5..b786a3d4c5 100644
--- a/integration-test/src/test/resources/application.yml
+++ b/integration-test/src/test/resources/application.yml
@@ -179,7 +179,7 @@ ncmp:
 
   timers:
     advised-modules-sync:
-      sleep-time-ms: 1000
+      sleep-time-ms: 1000000
     cm-handle-data-sync:
       sleep-time-ms: 30000
     subscription-forwarding:
diff --git a/integration-test/src/test/resources/data/ncmp-registry/innerNode.json b/integration-test/src/test/resources/data/inventory/cmHandleTemplate.json
index b6c65f3763..6577f4e560 100644
--- a/integration-test/src/test/resources/data/ncmp-registry/innerNode.json
+++ b/integration-test/src/test/resources/data/inventory/cmHandleTemplate.json
@@ -1,6 +1,6 @@
 {
-  "id": "cm-CMHANDLE_ID_HERE",
-  "alternate-id": "alt-CMHANDLE_ID_HERE",
+  "id": "cm-CM_HANDLE_ID_HERE",
+  "alternate-id": "alt-CM_HANDLE_ID_HERE",
   "module-set-tag": "my-module-set-tag",
   "dmi-service-name": "http://ncmp-dmi-plugin-stub:8080",
   "dmi-data-service-name": "",
@@ -21,4 +21,4 @@
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/integration-test/src/test/resources/data/ncmp-registry/innerCmHandleNode.json b/integration-test/src/test/resources/data/inventory/cmHandleWithAlternateIdTemplate.json
index 88446c4a0f..88446c4a0f 100644
--- a/integration-test/src/test/resources/data/ncmp-registry/innerCmHandleNode.json
+++ b/integration-test/src/test/resources/data/inventory/cmHandleWithAlternateIdTemplate.json
diff --git a/integration-test/src/test/resources/data/ncmp-registry/dmi-registry@2024-02-23.yang b/integration-test/src/test/resources/data/inventory/dmi-registry@2024-02-23.yang
index d7b4ff7550..d7b4ff7550 100644
--- a/integration-test/src/test/resources/data/ncmp-registry/dmi-registry@2024-02-23.yang
+++ b/integration-test/src/test/resources/data/inventory/dmi-registry@2024-02-23.yang
diff --git a/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java
index 8f904cc5f2..789201ffce 100644
--- a/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java
+++ b/policy-executor-stub/src/main/java/org/onap/cps/policyexecutor/stub/controller/Sleeper.java
@@ -24,8 +24,8 @@ import java.util.concurrent.TimeUnit;
 import org.springframework.stereotype.Service;
 
 /**
- * This class is a successfull experiment to extract out sleep functionality so the interrupted exception handling can
- * be covered with a test (e.g. using spy ion Sleeper) and help to get too 100% code coverage.
+ * This class is to extract out sleep functionality so the interrupted exception handling can
+ * be covered with a test (e.g. using spy on Sleeper) and help to get too 100% code coverage.
  */
 @Service
 public class Sleeper {