CPS Delta API 1: Delta between 2 anchors

- CPS Delta Feature Part 1: To find delta between two anchors
   - created new endpoint deltaByDataspaceAndAnchors
   - endpoint to take dataspaceName, source anchor, target anchor,
     xpath, descendants as input
   - added new service CpsDeltaService
   - added method to find delta between DataNodes:
     getDeltaReport
   - added method to find removed data nodes: getRemovedDeltaReports
   - added method to get Added DataNodes: getAddedDeltaReports
   - added method to get Map of xpath to DataNode: convertToXPathToDataNodesMap
   - added a POJO for delta report
   - Added new JSON data for delta feature testing
   - Added groovy test files CpsDeltaServiceImplSpec and DeltaReportBuilderSpec
   - code related to update operation, will be added in
     separate commit

Issue-ID: CPS-1824
Signed-off-by: Arpit Singh <as00745003@techmahindra.com>
Change-Id: I313f0f71d04b03878be7643f709d8af1aa6df6ba

10 files changed, 461 insertions, 4 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java b/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
index 6a2cac467..c9879595a 100644
--- a/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
+++ b/cps-service/src/main/java/org/onap/cps/api/CpsDataService.java
@@ -26,9 +26,11 @@ package org.onap.cps.api;
 
 import java.time.OffsetDateTime;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import org.onap.cps.spi.FetchDescendantsOption;
 import org.onap.cps.spi.model.DataNode;
+import org.onap.cps.spi.model.DeltaReport;
 import org.onap.cps.utils.ContentType;
 
 /*
@@ -298,4 +300,19 @@ public interface CpsDataService {
      * @param timeoutInMilliseconds lock attempt timeout in milliseconds
      */
     void lockAnchor(String sessionID, String dataspaceName, String anchorName, Long timeoutInMilliseconds);
+
+    /**
+     * Retrieves the delta between two anchors by xpath within a dataspace.
+     *
+     * @param dataspaceName          dataspace name
+     * @param sourceAnchorName       source anchor name
+     * @param targetAnchorName       target anchor name
+     * @param xpath                  xpath
+     * @param fetchDescendantsOption defines the scope of data to fetch: either single node or all the descendant
+     *                               nodes (recursively) as well
+     * @return                       list containing {@link DeltaReport} objects
+     */
+    List<DeltaReport> getDeltaByDataspaceAndAnchors(String dataspaceName, String sourceAnchorName,
+                                                    String targetAnchorName, String xpath,
+                                                    FetchDescendantsOption fetchDescendantsOption);
 }
diff --git a/cps-service/src/main/java/org/onap/cps/api/CpsDeltaService.java b/cps-service/src/main/java/org/onap/cps/api/CpsDeltaService.java
new file mode 100644
index 000000000..d806c208a
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/api/CpsDeltaService.java
@@ -0,0 +1,42 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.api;
+
+import java.util.Collection;
+import java.util.List;
+import org.onap.cps.spi.model.DataNode;
+import org.onap.cps.spi.model.DeltaReport;
+
+public interface CpsDeltaService {
+
+    /**
+     * Retrieves delta between source data nodes and target data nodes. Source data nodes contain the data which acts as
+     * the point of reference for delta report, whereas target data nodes contain the data being compared against
+     * source data node. List of {@link DeltaReport}. Each Delta Report contains information such as action, xpath,
+     * source-payload and target-payload.
+     *
+     * @param sourceDataNodes  collection of {@link DataNode} as source/reference for delta generation
+     * @param targetDataNodes  collection of {@link DataNode} as target data for delta generation
+     * @return                 list of {@link DeltaReport} containing delta information
+     */
+    List<DeltaReport> getDeltaReports(Collection<DataNode> sourceDataNodes,
+                                      Collection<DataNode> targetDataNodes);
+}
diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
index 1d68450f8..e74e0ad24 100755
--- a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
+++ b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDataServiceImpl.java
@@ -34,12 +34,14 @@ import java.time.OffsetDateTime;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 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.CpsDeltaService;
 import org.onap.cps.cpspath.parser.CpsPathUtil;
 import org.onap.cps.notification.NotificationService;
 import org.onap.cps.notification.Operation;
@@ -49,6 +51,7 @@ import org.onap.cps.spi.exceptions.DataValidationException;
 import org.onap.cps.spi.model.Anchor;
 import org.onap.cps.spi.model.DataNode;
 import org.onap.cps.spi.model.DataNodeBuilder;
+import org.onap.cps.spi.model.DeltaReport;
 import org.onap.cps.spi.utils.CpsValidator;
 import org.onap.cps.utils.ContentType;
 import org.onap.cps.utils.TimedYangParser;
@@ -70,6 +73,7 @@ public class CpsDataServiceImpl implements CpsDataService {
     private final NotificationService notificationService;
     private final CpsValidator cpsValidator;
     private final TimedYangParser timedYangParser;
+    private final CpsDeltaService cpsDeltaService;
 
     @Override
     public void saveData(final String dataspaceName, final String anchorName, final String nodeData,
@@ -215,6 +219,22 @@ public class CpsDataServiceImpl implements CpsDataService {
     }
 
     @Override
+    @Timed(value = "cps.data.service.get.delta",
+            description = "Time taken to get delta between anchors")
+    public List<DeltaReport> getDeltaByDataspaceAndAnchors(final String dataspaceName,
+                                                           final String sourceAnchorName,
+                                                           final String targetAnchorName, final String xpath,
+                                                           final FetchDescendantsOption fetchDescendantsOption) {
+
+        final Collection<DataNode> sourceDataNodes = getDataNodesForMultipleXpaths(dataspaceName,
+                sourceAnchorName, Collections.singletonList(xpath), fetchDescendantsOption);
+        final Collection<DataNode> targetDataNodes = getDataNodesForMultipleXpaths(dataspaceName,
+                targetAnchorName, Collections.singletonList(xpath), fetchDescendantsOption);
+
+        return cpsDeltaService.getDeltaReports(sourceDataNodes, targetDataNodes);
+    }
+
+    @Override
     @Timed(value = "cps.data.service.datanode.descendants.update",
         description = "Time taken to update a data node and descendants")
     public void updateDataNodeAndDescendants(final String dataspaceName, final String anchorName,
diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java
new file mode 100644
index 000000000..683ddce3d
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java
@@ -0,0 +1,108 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.api.impl;
+
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import lombok.NoArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.onap.cps.api.CpsDeltaService;
+import org.onap.cps.spi.model.DataNode;
+import org.onap.cps.spi.model.DeltaReport;
+import org.onap.cps.spi.model.DeltaReportBuilder;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+@NoArgsConstructor
+public class CpsDeltaServiceImpl implements CpsDeltaService {
+
+    @Override
+    public List<DeltaReport> getDeltaReports(final Collection<DataNode> sourceDataNodes,
+                                             final Collection<DataNode> targetDataNodes) {
+
+        final List<DeltaReport> deltaReport = new ArrayList<>();
+
+        final Map<String, DataNode> xpathToSourceDataNodes = convertToXPathToDataNodesMap(sourceDataNodes);
+        final Map<String, DataNode> xpathToTargetDataNodes = convertToXPathToDataNodesMap(targetDataNodes);
+
+        deltaReport.addAll(getRemovedDeltaReports(xpathToSourceDataNodes, xpathToTargetDataNodes));
+
+        deltaReport.addAll(getAddedDeltaReports(xpathToSourceDataNodes, xpathToTargetDataNodes));
+
+        return Collections.unmodifiableList(deltaReport);
+    }
+
+    private static Map<String, DataNode> convertToXPathToDataNodesMap(
+                                                                    final Collection<DataNode> dataNodes) {
+        final Map<String, DataNode> xpathToDataNode = new LinkedHashMap<>();
+        for (final DataNode dataNode : dataNodes) {
+            xpathToDataNode.put(dataNode.getXpath(), dataNode);
+            final Collection<DataNode> childDataNodes = dataNode.getChildDataNodes();
+            if (!childDataNodes.isEmpty()) {
+                xpathToDataNode.putAll(convertToXPathToDataNodesMap(childDataNodes));
+            }
+        }
+        return xpathToDataNode;
+    }
+
+    private static List<DeltaReport> getRemovedDeltaReports(
+                                                            final Map<String, DataNode> xpathToSourceDataNodes,
+                                                            final Map<String, DataNode> xpathToTargetDataNodes) {
+
+        final List<DeltaReport> removedDeltaReportEntries = new ArrayList<>();
+        for (final Map.Entry<String, DataNode> entry: xpathToSourceDataNodes.entrySet()) {
+            final String xpath = entry.getKey();
+            final DataNode sourceDataNode = entry.getValue();
+            final DataNode targetDataNode = xpathToTargetDataNodes.get(xpath);
+
+            if (targetDataNode == null) {
+                final Map<String, Serializable> sourceDataNodeLeaves = sourceDataNode.getLeaves();
+                final DeltaReport removedData = new DeltaReportBuilder().actionRemove().withXpath(xpath)
+                        .withSourceData(sourceDataNodeLeaves).build();
+                removedDeltaReportEntries.add(removedData);
+            }
+        }
+        return removedDeltaReportEntries;
+    }
+
+    private static List<DeltaReport> getAddedDeltaReports(final Map<String, DataNode> xpathToSourceDataNodes,
+                                                          final Map<String, DataNode> xpathToTargetDataNodes) {
+
+        final List<DeltaReport> addedDeltaReportEntries = new ArrayList<>();
+        final Map<String, DataNode> xpathToAddedNodes = new LinkedHashMap<>(xpathToTargetDataNodes);
+        xpathToAddedNodes.keySet().removeAll(xpathToSourceDataNodes.keySet());
+        for (final Map.Entry<String, DataNode> entry: xpathToAddedNodes.entrySet()) {
+            final String xpath = entry.getKey();
+            final DataNode dataNode = entry.getValue();
+            final DeltaReport addedDataForDeltaReport = new DeltaReportBuilder().actionAdd().withXpath(xpath)
+                                .withTargetData(dataNode.getLeaves()).build();
+            addedDeltaReportEntries.add(addedDataForDeltaReport);
+        }
+        return addedDeltaReportEntries;
+    }
+}
diff --git a/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReport.java b/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReport.java
new file mode 100644
index 000000000..b9c05dcf0
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReport.java
@@ -0,0 +1,42 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.spi.model;
+
+import java.io.Serializable;
+import java.util.Map;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.Setter;
+
+@Setter(AccessLevel.PROTECTED)
+@Getter
+public class DeltaReport {
+
+    public static final String ADD_ACTION = "add";
+    public static final String REMOVE_ACTION = "remove";
+
+    DeltaReport() {}
+
+    private String action;
+    private String xpath;
+    private Map<String, Serializable> sourceData;
+    private Map<String, Serializable> targetData;
+}
diff --git a/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReportBuilder.java b/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReportBuilder.java
new file mode 100644
index 000000000..cef6ca3fa
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/spi/model/DeltaReportBuilder.java
@@ -0,0 +1,79 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.spi.model;
+
+import java.io.Serializable;
+import java.util.Map;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class DeltaReportBuilder {
+
+
+    private String action;
+    private String xpath;
+    private Map<String, Serializable> sourceData;
+    private Map<String, Serializable> targetData;
+
+    public DeltaReportBuilder withXpath(final String xpath) {
+        this.xpath = xpath;
+        return this;
+    }
+
+    public DeltaReportBuilder withSourceData(final Map<String, Serializable> sourceData) {
+        this.sourceData = sourceData;
+        return this;
+    }
+
+    public DeltaReportBuilder withTargetData(final Map<String, Serializable> targetData) {
+        this.targetData = targetData;
+        return this;
+    }
+
+    public DeltaReportBuilder actionAdd() {
+        this.action = DeltaReport.ADD_ACTION;
+        return this;
+    }
+
+    public DeltaReportBuilder actionRemove() {
+        this.action = DeltaReport.REMOVE_ACTION;
+        return this;
+    }
+
+    /**
+     * To create a single entry of {@link DeltaReport}.
+     *
+     * @return {@link DeltaReport}
+     */
+    public DeltaReport build() {
+        final DeltaReport deltaReport = new DeltaReport();
+        deltaReport.setAction(action);
+        deltaReport.setXpath(xpath);
+        if (sourceData != null && !sourceData.isEmpty()) {
+            deltaReport.setSourceData(sourceData);
+        }
+
+        if (targetData != null && !targetData.isEmpty()) {
+            deltaReport.setTargetData(targetData);
+        }
+        return deltaReport;
+    }
+}
diff --git a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
index e1d15d68a..a91459852 100644
--- a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
+++ b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDataServiceImplSpec.groovy
@@ -25,6 +25,7 @@ package org.onap.cps.api.impl
 
 import org.onap.cps.TestUtils
 import org.onap.cps.api.CpsAdminService
+import org.onap.cps.api.CpsDeltaService
 import org.onap.cps.notification.NotificationService
 import org.onap.cps.notification.Operation
 import org.onap.cps.spi.CpsDataPersistenceService
@@ -37,12 +38,14 @@ import org.onap.cps.spi.exceptions.SessionTimeoutException
 import org.onap.cps.spi.model.Anchor
 import org.onap.cps.spi.model.DataNode
 import org.onap.cps.spi.model.DataNodeBuilder
+import org.onap.cps.spi.model.DeltaReportBuilder
+import org.onap.cps.spi.utils.CpsValidator
 import org.onap.cps.utils.ContentType
 import org.onap.cps.utils.TimedYangParser
 import org.onap.cps.yang.YangTextSchemaSourceSet
 import org.onap.cps.yang.YangTextSchemaSourceSetBuilder
+import spock.lang.Shared
 import spock.lang.Specification
-import org.onap.cps.spi.utils.CpsValidator
 
 import java.time.OffsetDateTime
 import java.util.stream.Collectors
@@ -54,18 +57,28 @@ class CpsDataServiceImplSpec extends Specification {
     def mockNotificationService = Mock(NotificationService)
     def mockCpsValidator = Mock(CpsValidator)
     def timedYangParser = new TimedYangParser()
+    def mockCpsDeltaService = Mock(CpsDeltaService);
 
     def objectUnderTest = new CpsDataServiceImpl(mockCpsDataPersistenceService, mockCpsAdminService,
-            mockYangTextSchemaSourceSetCache, mockNotificationService, mockCpsValidator, timedYangParser)
+            mockYangTextSchemaSourceSetCache, mockNotificationService, mockCpsValidator, timedYangParser, mockCpsDeltaService)
 
     def setup() {
+
         mockCpsAdminService.getAnchor(dataspaceName, anchorName) >> anchor
+        mockCpsAdminService.getAnchor(dataspaceName, ANCHOR_NAME_1) >> anchor1
+        mockCpsAdminService.getAnchor(dataspaceName, ANCHOR_NAME_2) >> anchor2
     }
 
+    @Shared
+    static def ANCHOR_NAME_1 = 'some-anchor-1'
+    @Shared
+    static def ANCHOR_NAME_2 = 'some-anchor-2'
     def dataspaceName = 'some-dataspace'
     def anchorName = 'some-anchor'
     def schemaSetName = 'some-schema-set'
     def anchor = Anchor.builder().name(anchorName).dataspaceName(dataspaceName).schemaSetName(schemaSetName).build()
+    def anchor1 = Anchor.builder().name(ANCHOR_NAME_1).dataspaceName(dataspaceName).schemaSetName(schemaSetName).build()
+    def anchor2 = Anchor.builder().name(ANCHOR_NAME_2).dataspaceName(dataspaceName).schemaSetName(schemaSetName).build()
     def observedTimestamp = OffsetDateTime.now()
 
     def 'Saving #scenario data.'() {
@@ -228,6 +241,22 @@ class CpsDataServiceImplSpec extends Specification {
             fetchDescendantsOption << [FetchDescendantsOption.OMIT_DESCENDANTS, FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS]
     }
 
+    def 'Get delta between 2 anchors'() {
+        given: 'some xpath, source and target data nodes'
+            def xpath = '/xpath'
+            def sourceDataNodes = [new DataNodeBuilder().withXpath(xpath).build()]
+            def targetDataNodes = [new DataNodeBuilder().withXpath(xpath).build()]
+        when: 'attempt to get delta between 2 anchors'
+            objectUnderTest.getDeltaByDataspaceAndAnchors(dataspaceName, ANCHOR_NAME_1, ANCHOR_NAME_2, xpath, FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS)
+        then: 'the dataspace and anchor names are validated'
+            2 * mockCpsValidator.validateNameCharacters(_)
+        and: 'data nodes are fetched using appropriate persistence layer method'
+            mockCpsDataPersistenceService.getDataNodesForMultipleXpaths(dataspaceName, ANCHOR_NAME_1, [xpath], FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS) >> sourceDataNodes
+            mockCpsDataPersistenceService.getDataNodesForMultipleXpaths(dataspaceName, ANCHOR_NAME_2, [xpath], FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS) >> targetDataNodes
+        and: 'appropriate delta service method is invoked once with correct source and target data nodes'
+            1 * mockCpsDeltaService.getDeltaReports(sourceDataNodes, targetDataNodes)
+    }
+
     def 'Update data node leaves: #scenario.'() {
         given: 'schema set for given anchor and dataspace references test-tree model'
             setupSchemaSetMocks('test-tree.yang')
diff --git a/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDeltaServiceImplSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDeltaServiceImplSpec.groovy
new file mode 100644
index 000000000..a4f433973
--- /dev/null
+++ b/cps-service/src/test/groovy/org/onap/cps/api/impl/CpsDeltaServiceImplSpec.groovy
@@ -0,0 +1,66 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.api.impl
+
+import org.onap.cps.spi.model.DataNode
+import org.onap.cps.spi.model.DataNodeBuilder
+import spock.lang.Shared
+import spock.lang.Specification
+
+class CpsDeltaServiceImplSpec extends Specification{
+
+    def objectUnderTest = new CpsDeltaServiceImpl()
+
+    @Shared
+    def dataNodeWithLeafAndChildDataNode = [new DataNodeBuilder().withXpath('/parent').withLeaves(['parent-leaf': 'parent-payload'])
+                            .withChildDataNodes([new DataNodeBuilder().withXpath("/parent/child").withLeaves('child-leaf': 'child-payload').build()]).build()]
+    @Shared
+    def dataNodeWithChildDataNode = [new DataNodeBuilder().withXpath('/parent').withLeaves(['parent-leaf': 'parent-payload'])
+                                             .withChildDataNodes([new DataNodeBuilder().withXpath("/parent/child").build()]).build()]
+    @Shared
+    def emptyDataNode = [new DataNodeBuilder().withXpath('/parent').build()]
+
+    def 'Get delta between data nodes for removed data where source data node has #scenario'() {
+        when: 'attempt to get delta between 2 data nodes'
+            def result = objectUnderTest.getDeltaReports(sourceDataNode as Collection<DataNode>, emptyDataNode)
+        then: 'the delta report contains "remove" action with right data'
+            assert result.first().action.equals("remove")
+            assert result.first().xpath == "/parent/child"
+            assert result.first().sourceData == expectedSourceData
+        where: 'following data was used'
+            scenario       | sourceDataNode                   || expectedSourceData
+            'leaf data'    | dataNodeWithLeafAndChildDataNode || ['child-leaf': 'child-payload']
+            'no leaf data' | dataNodeWithChildDataNode        || null
+    }
+
+    def 'Get delta between data nodes with new data where target data node has #scenario'() {
+        when: 'attempt to get delta between 2 data nodes'
+            def result = objectUnderTest.getDeltaReports(emptyDataNode, targetDataNode)
+        then: 'the delta report contains "add" action with right data'
+            assert result.first().action.equals("add")
+            assert result.first().xpath == "/parent/child"
+            assert result.first().targetData == expectedTargetData
+        where: 'following data was used'
+            scenario       | targetDataNode                   || expectedTargetData
+            'leaf data'    | dataNodeWithLeafAndChildDataNode || ['child-leaf': 'child-payload']
+            'no leaf data' | dataNodeWithChildDataNode        || null
+    }
+}
diff --git a/cps-service/src/test/groovy/org/onap/cps/api/impl/E2ENetworkSliceSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/api/impl/E2ENetworkSliceSpec.groovy
index 75f29746d..1b873ec12 100755
--- a/cps-service/src/test/groovy/org/onap/cps/api/impl/E2ENetworkSliceSpec.groovy
+++ b/cps-service/src/test/groovy/org/onap/cps/api/impl/E2ENetworkSliceSpec.groovy
@@ -3,7 +3,7 @@
  * Copyright (C) 2021-2023 Nordix Foundation.

  * Modifications Copyright (C) 2021-2022 Bell Canada.

  * Modifications Copyright (C) 2021 Pantheon.tech

- * Modifications Copyright (C) 2022 TechMahindra Ltd.

+ * Modifications Copyright (C) 2022-2023 TechMahindra Ltd.

  * ================================================================================

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

@@ -25,6 +25,7 @@ package org.onap.cps.api.impl
 

 import org.onap.cps.TestUtils

 import org.onap.cps.api.CpsAdminService

+import org.onap.cps.api.CpsDeltaService

 import org.onap.cps.notification.NotificationService

 import org.onap.cps.spi.CpsDataPersistenceService

 import org.onap.cps.spi.CpsModulePersistenceService

@@ -45,12 +46,13 @@ class E2ENetworkSliceSpec extends Specification {
     def mockCpsValidator = Mock(CpsValidator)

     def timedYangTextSchemaSourceSetBuilder = new TimedYangTextSchemaSourceSetBuilder()

     def timedYangParser = new TimedYangParser()

+    def mockCpsDeltaService = Mock(CpsDeltaService)

 

     def cpsModuleServiceImpl = new CpsModuleServiceImpl(mockModuleStoreService,

             mockYangTextSchemaSourceSetCache, mockCpsAdminService, mockCpsValidator,timedYangTextSchemaSourceSetBuilder)

 

     def cpsDataServiceImpl = new CpsDataServiceImpl(mockDataStoreService, mockCpsAdminService,

-            mockYangTextSchemaSourceSetCache, mockNotificationService, mockCpsValidator, timedYangParser)

+            mockYangTextSchemaSourceSetCache, mockNotificationService, mockCpsValidator, timedYangParser, mockCpsDeltaService)

 

     def dataspaceName = 'someDataspace'

     def anchorName = 'someAnchor'

diff --git a/cps-service/src/test/groovy/org/onap/cps/spi/model/DeltaReportBuilderSpec.groovy b/cps-service/src/test/groovy/org/onap/cps/spi/model/DeltaReportBuilderSpec.groovy
new file mode 100644
index 000000000..e19d12042
--- /dev/null
+++ b/cps-service/src/test/groovy/org/onap/cps/spi/model/DeltaReportBuilderSpec.groovy
@@ -0,0 +1,52 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.spi.model
+
+import spock.lang.Specification
+
+class DeltaReportBuilderSpec extends Specification{
+
+    def 'Generating delta report with  for add action'() {
+        when: 'delta report is generated'
+            def result = new DeltaReportBuilder()
+                    .actionAdd()
+                    .withXpath('/xpath')
+                    .withTargetData(['data':'leaf-data'])
+                    .build()
+        then: 'the delta report contains the "add" action with expected target data'
+            assert result.action == 'add'
+            assert result.xpath == '/xpath'
+            assert result.targetData == ['data': 'leaf-data']
+    }
+
+    def 'Generating delta report with attributes for remove action'() {
+        when: 'delta report is generated'
+            def result = new DeltaReportBuilder()
+                    .actionRemove()
+                    .withXpath('/xpath')
+                    .withSourceData(['data':'leaf-data'])
+                    .build()
+        then: 'the delta report contains the "remove" action with expected source data'
+            assert result.action == 'remove'
+            assert result.xpath == '/xpath'
+            assert result.sourceData == ['data': 'leaf-data']
+    }
+}