YANG sub module linking + unsupported yang construct + defect fix

Change-Id: I224c8c14ee2111f6844278cb540c48651544f59b
diff --git a/src/test/java/org/onosproject/yangutils/parser/impl/TreeWalkListenerTest.java b/src/test/java/org/onosproject/yangutils/parser/impl/TreeWalkListenerTest.java
new file mode 100644
index 0000000..cebd680
--- /dev/null
+++ b/src/test/java/org/onosproject/yangutils/parser/impl/TreeWalkListenerTest.java
@@ -0,0 +1,55 @@
+/*
+ * 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;
+
+import java.io.IOException;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+
+/**
+ * Test cases for testing tree walk listener functionality.
+ */
+public class TreeWalkListenerTest {
+
+    private final YangUtilsParserManager manager = new YangUtilsParserManager();
+
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+    /**
+     * Checks whether exception is thrown for ordered statement.
+     */
+    @Test
+    public void processOrderedByStatement() throws IOException, ParserException {
+        thrown.expect(ParserException.class);
+        thrown.expectMessage("YANG file error : \"ordered-by\" is not supported in current version, please check wiki" +
+                " for YANG utils road map.");
+        manager.getDataModel("src/test/resources/OrderedByStatement.yang");
+    }
+
+    /**
+     * Checks whether exception is thrown for anyxml statement.
+     */
+    @Test
+    public void processAnyXmlStatement() throws IOException, ParserException {
+        thrown.expect(ParserException.class);
+        thrown.expectMessage("YANG file error : \"anyxml\" is not supported.");
+        manager.getDataModel("src/test/resources/AnyxmlStatement.yang");
+    }
+}