[ONOS-3880, 3881] Yang Listener for Module and Sub-Module

Change-Id: Iee75c3e04af9b66ebc38acb3396aa4c54af5a268
diff --git a/utils/yangutils/src/test/java/org/onosproject/yangutils/parser/impl/listeners/ImportListenerTest.java b/utils/yangutils/src/test/java/org/onosproject/yangutils/parser/impl/listeners/ImportListenerTest.java
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+++ b/utils/yangutils/src/test/java/org/onosproject/yangutils/parser/impl/listeners/ImportListenerTest.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2016 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.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 static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Test cases for testing import listener functionality.
+ */
+public class ImportListenerTest {
+
+    private final YangUtilsParserManager manager = new YangUtilsParserManager();
+
+    /**
+     * Checks if mandatory parameter prefix is present in import.
+     */
+    @Test(expected = ParserException.class)
+    public void processImportWithoutPrefix() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportWithoutPrefix.yang");
+    }
+
+    /**
+     * Checks that prefix must be present only once in import.
+     */
+    @Test(expected = ParserException.class)
+    public void processImportWithDualPrefix() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportWithDualPrefix.yang");
+    }
+
+    /**
+     * Checks for the correct order of prefix in import.
+     */
+    @Test(expected = ParserException.class)
+    public void processImportInvalidOrder() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportInvalidOrder.yang");
+    }
+
+    /**
+     * Checks if import listener updates the data model tree.
+     */
+    @Test
+    public void processImportValidEntry() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportValidEntry.yang");
+
+        // Checks for the revision value in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getRevision(), is("2015-02-03"));
+        // Checks for the prefix id in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getPrefixId(), is("On2"));
+        // Checks for the module name in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getModuleName(), is("ietf"));
+    }
+
+    /**
+     * Checks if optional parameter revision is not mandatory in import.
+     */
+    @Test
+    public void processImportWithoutRevision() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportWithoutRevision.yang");
+
+        // Checks for the prefix id in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getPrefixId(), is("On2"));
+        // Checks for the module name in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getModuleName(), is("ietf"));
+    }
+
+    /**
+     * Checks if multiple imports are allowed.
+     */
+    @Test()
+    public void processImportMultipleInstance() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ImportMultipleInstance.yang");
+
+        // Checks for the prefix id in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getPrefixId(), is("On2"));
+        // Checks for the module name in data model tree.
+        assertThat(((YangModule) node).getImportList().get(0).getModuleName(), is("ietf"));
+
+        // Checks for the prefix id in data model tree.
+        assertThat(((YangModule) node).getImportList().get(1).getPrefixId(), is("On3"));
+        // Checks for the module name in data model tree.
+        assertThat(((YangModule) node).getImportList().get(1).getModuleName(), is("itut"));
+    }
+}
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