diff --git a/apps/yms/app/src/test/java/org/onosproject/yms/app/ypm/DefaultYpmNodeTest.java b/apps/yms/app/src/test/java/org/onosproject/yms/app/ypm/DefaultYpmNodeTest.java
new file mode 100644
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+++ b/apps/yms/app/src/test/java/org/onosproject/yms/app/ypm/DefaultYpmNodeTest.java
@@ -0,0 +1,193 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.
+ */
+
+package org.onosproject.yms.app.ypm;
+
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+
+import org.onosproject.yms.ypm.YpmContext;
+import org.onosproject.yms.ypm.DefaultYpmNode;
+
+/**
+ * Unit tests for DefaultYpmNode class.
+ */
+public class DefaultYpmNodeTest {
+    private final String logicalName = "logicalYpmNode";
+    private final String moduleName1 = "portPairModule1";
+    private final String moduleName2 = "portPairModule2";
+    private final String xNodeName = "x";
+    private final String yNodeName = "y";
+    private final String zNodeName = "z";
+    private final String x1NodeName = "x1";
+    private final String x2NodeName = "x2";
+    private final String y1NodeName = "y1";
+    private final String y2NodeName = "y2";
+    private final String z1NodeName = "z1";
+    private final String z2NodeName = "z2";
+
+    /**
+     * Constructs ypm tree with single module.
+     *
+     * @return ypm tree root node
+     */
+    private YpmContext constructYpmTreeSingleModule() {
+        // Create logical node
+        DefaultYpmNode rootNode = new DefaultYpmNode(logicalName);
+        // Create module node with moduleName1
+        rootNode.addChild(moduleName1); // child to logical node
+        YpmContext moduleNode = rootNode.getChild(moduleName1);
+        moduleNode.addChild(xNodeName); // child to module node
+        moduleNode.addChild(yNodeName); // sibling node to child node "x"
+        YpmContext xNode = moduleNode.getChild("x");
+        xNode.addSibling(zNodeName); // sibling node to child node "x"
+        xNode.addChild(x1NodeName); // child to node x
+        xNode.addChild(x2NodeName); // child to node x
+        YpmContext yNode = moduleNode.getChild(yNodeName);
+        yNode.addChild(y1NodeName); // child to node y
+        yNode.addChild(y2NodeName); // child to node y
+        YpmContext zNode = moduleNode.getChild(zNodeName);
+        zNode.addChild(z1NodeName); // child to node z
+        zNode.addChild(z2NodeName); // child to node z
+        return rootNode;
+    }
+
+    /**
+     * Constructs ypm tree with multi module.
+     *
+     * @return ypm tree root node
+     */
+    private YpmContext constructYpmTreeMultiModule(DefaultYpmNode rootNode) {
+        rootNode.addChild(moduleName2); // child to logical node
+        YpmContext moduleNode = rootNode.getChild(moduleName2);
+        moduleNode.addChild(xNodeName); // child to module node
+        moduleNode.addChild(yNodeName); // sibling node to child node "x"
+        YpmContext xNode = moduleNode.getChild("x");
+        xNode.addSibling(zNodeName); // sibling node to child node "x"
+        xNode.addChild(x1NodeName); // child to node x
+        xNode.addChild(x2NodeName); // child to node x
+        YpmContext yNode = moduleNode.getChild(yNodeName);
+        yNode.addChild(y1NodeName); // child to node y
+        yNode.addChild(y2NodeName); // child to node y
+        YpmContext zNode = moduleNode.getChild(zNodeName);
+        zNode.addChild(z1NodeName); // child to node z
+        zNode.addChild(z2NodeName); // child to node z
+        return rootNode;
+    }
+
+    /**
+     * Checks ypm tree single module construction.
+     */
+    @Test
+    public void testYpmTreeSingleModuleConstruction() {
+        DefaultYpmNode rootNode = (DefaultYpmNode) constructYpmTreeSingleModule();
+        // Check one by one node
+        String name = rootNode.getName();
+        assertThat(name, is(logicalName));
+        YpmContext moduleNode = rootNode.getChild(moduleName1);
+        assertThat(moduleNode.getName(), is(moduleName1));
+        YpmContext ypmNode = moduleNode.getChild(xNodeName);
+        assertThat(ypmNode.getName(), is(xNodeName));
+        // Check sibling by using getNextSibling();
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, notNullValue()); // either y or z should be there as sibling
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, notNullValue()); // either y or z should be there as sibling
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, nullValue()); // last sibling point to next sibling as null
+        // Check sibling by using getPreviousSibling()
+        ypmNode = moduleNode.getChild(zNodeName);
+        assertThat(ypmNode.getName(), is(zNodeName));
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, notNullValue()); // either x or y should be there as sibling
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, notNullValue()); // either x or y should be there as sibling
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, nullValue()); // last sibling point to next sibling as null
+        // Checks the child x1 and x2
+        ypmNode = moduleNode.getChild(xNodeName);
+        ypmNode = ypmNode.getChild(x1NodeName);
+        assertThat(ypmNode.getName(), is(x1NodeName));
+        ypmNode = ypmNode.getSibling(x2NodeName);
+        assertThat(ypmNode.getName(), is(x2NodeName));
+        // Checks the child y1 and y2
+        ypmNode = moduleNode.getChild(yNodeName);
+        ypmNode = ypmNode.getChild(y1NodeName);
+        assertThat(ypmNode.getName(), is(y1NodeName));
+        ypmNode = ypmNode.getSibling(y2NodeName);
+        assertThat(ypmNode.getName(), is(y2NodeName));
+        // Checks the child z1 and z2
+        ypmNode = moduleNode.getChild(zNodeName);
+        ypmNode = ypmNode.getChild(z1NodeName);
+        assertThat(ypmNode.getName(), is(z1NodeName));
+        ypmNode = ypmNode.getSibling(z2NodeName);
+        assertThat(ypmNode.getName(), is(z2NodeName));
+    }
+
+    /**
+     * Checks ypm tree multiple module construction.
+     */
+    @Test
+    public void testYpmTreeMultiModuleConstruction() {
+        DefaultYpmNode rootNode = (DefaultYpmNode) constructYpmTreeSingleModule();
+        rootNode = (DefaultYpmNode) constructYpmTreeMultiModule(rootNode);
+        // Check one by one node
+        String name = rootNode.getName();
+        assertThat(name, is(logicalName));
+        YpmContext moduleNode = rootNode.getChild(moduleName2);
+        assertThat(moduleNode.getName(), is(moduleName2));
+        YpmContext ypmNode = moduleNode.getChild(xNodeName);
+        assertThat(ypmNode.getName(), is(xNodeName));
+        // Check sibling by using getNextSibling();
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, notNullValue()); // either y or z should be there as sibling
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, notNullValue()); // either y or z should be there as sibling
+        ypmNode = ypmNode.getNextSibling();
+        assertThat(ypmNode, nullValue()); // last sibling point to next sibling as null
+        // Check sibling by using getPreviousSibling()
+        ypmNode = moduleNode.getChild(zNodeName);
+        assertThat(ypmNode.getName(), is(zNodeName));
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, notNullValue()); // either x or y should be there as sibling
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, notNullValue()); // either x or y should be there as sibling
+        ypmNode = ypmNode.getPreviousSibling();
+        assertThat(ypmNode, nullValue()); // last sibling point to next sibling as null
+        // Checks the child x1 and x2
+        ypmNode = moduleNode.getChild(xNodeName);
+        ypmNode = ypmNode.getChild(x1NodeName);
+        assertThat(ypmNode.getName(), is(x1NodeName));
+        ypmNode = ypmNode.getSibling(x2NodeName);
+        assertThat(ypmNode.getName(), is(x2NodeName));
+        // Checks the child y1 and y2
+        ypmNode = moduleNode.getChild(yNodeName);
+        ypmNode = ypmNode.getChild(y1NodeName);
+        assertThat(ypmNode.getName(), is(y1NodeName));
+        ypmNode = ypmNode.getSibling(y2NodeName);
+        assertThat(ypmNode.getName(), is(y2NodeName));
+        // Checks the child z1 and z2
+        ypmNode = moduleNode.getChild(zNodeName);
+        ypmNode = ypmNode.getChild(z1NodeName);
+        assertThat(ypmNode.getName(), is(z1NodeName));
+        ypmNode = ypmNode.getSibling(z2NodeName);
+        assertThat(ypmNode.getName(), is(z2NodeName));
+    }
+}