diff --git a/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/WhenListenerTest.java b/plugin/src/test/java/org/onosproject/yangutils/parser/impl/listeners/WhenListenerTest.java
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+/*
+ * 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.yangutils.parser.impl.listeners;
+
+import org.junit.Test;
+import org.onosproject.yangutils.datamodel.YangContainer;
+import org.onosproject.yangutils.datamodel.YangLeaf;
+import org.onosproject.yangutils.datamodel.YangList;
+import org.onosproject.yangutils.datamodel.YangModule;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.YangUtilsParserManager;
+
+import java.io.IOException;
+import java.util.ListIterator;
+
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Test cases for testing when listener functionality.
+ */
+public class WhenListenerTest {
+
+    private final YangUtilsParserManager manager = new YangUtilsParserManager();
+
+    /**
+     * Checks if when listener updates the data model.
+     */
+    @Test
+    public void processContainerSubStatementWhen() throws IOException, ParserException {
+        YangNode node = manager.getDataModel("src/test/resources/ContainerSubStatementWhen.yang");
+
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangList yangList = (YangList) yangNode.getChild();
+        assertThat(yangList.getName(), is("interface-switching-capability"));
+
+        YangContainer container = (YangContainer) yangList.getNextSibling();
+        assertThat(container.getName(), is("time-division-multiplex-capable"));
+
+        String expectedConstraint = "../switching-capability = 'TDM'";
+        assertThat(container.getWhen().getCondition(), is(expectedConstraint));
+    }
+
+    /**
+     * Checks if when listener updates the data model.
+     */
+    @Test
+    public void processLeafSubStatementWhen() throws IOException, ParserException {
+        YangNode node = manager.getDataModel("src/test/resources/LeafSubStatementWhen.yang");
+
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        ListIterator<YangLeaf> leafIterator = yangNode.getListOfLeaf().listIterator();
+        YangLeaf leafInfo = leafIterator.next();
+
+        assertThat(leafInfo.getWhen().getCondition(), is("ifType != 'ethernet'"));
+    }
+}
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