diff --git a/plugin/src/test/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtilTest.java b/plugin/src/test/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtilTest.java
new file mode 100644
index 0000000..5fd728b
--- /dev/null
+++ b/plugin/src/test/java/org/onosproject/yangutils/utils/io/impl/FileSystemUtilTest.java
@@ -0,0 +1,148 @@
+/*
+ * 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.utils.io.impl;
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+import org.junit.Test;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaModule;
+import org.onosproject.yangutils.translator.tojava.utils.YangPluginConfig;
+
+import static org.apache.commons.io.FileUtils.deleteDirectory;
+import static org.hamcrest.core.Is.is;
+import static org.hamcrest.core.IsNot.not;
+import static org.junit.Assert.assertThat;
+import static org.onosproject.yangutils.utils.UtilConstants.PERIOD;
+import static org.onosproject.yangutils.utils.UtilConstants.SLASH;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.appendFileContents;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.createPackage;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.doesPackageExist;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.updateFileHandle;
+
+/**
+ * Tests the file handle utilities.
+ */
+public final class FileSystemUtilTest {
+
+    private static final String BASE_DIR_PKG = "target.UnitTestCase.";
+    private static final String BASE_PKG = "target/UnitTestCase";
+    private static final String TEST_DATA_1 = "This is to append a text to the file first1\n";
+    private static final String TEST_DATA_2 = "This is next second line\n";
+    private static final String TEST_DATA_3 = "This is next third line in the file";
+    private static final String TEST_FILE = "testFile";
+    private static final String SOURCE_TEST_FILE = "sourceTestFile";
+    private static final String DIR_PATH = "exist1.exist2.exist3";
+    private static final String PKG_INFO = "package-info.java";
+
+    /**
+     * A private constructor is tested.
+     *
+     * @throws SecurityException if any security violation is observed
+     * @throws NoSuchMethodException if when the method is not found
+     * @throws IllegalArgumentException if there is illegal argument found
+     * @throws InstantiationException if instantiation is provoked for the private constructor
+     * @throws IllegalAccessException if instance is provoked or a method is provoked
+     * @throws InvocationTargetException when an exception occurs by the method or constructor
+     */
+    @Test
+    public void callPrivateConstructors()
+            throws SecurityException, NoSuchMethodException, IllegalArgumentException,
+            InstantiationException, IllegalAccessException, InvocationTargetException {
+
+        Class<?>[] classesToConstruct = {FileSystemUtil.class };
+        for (Class<?> clazz : classesToConstruct) {
+            Constructor<?> constructor = clazz.getDeclaredConstructor();
+            constructor.setAccessible(true);
+            assertThat(null, not(constructor.newInstance()));
+        }
+    }
+
+    /**
+     * This test case checks the contents to be written in the file.
+     *
+     * @throws IOException when fails to create a test file
+     */
+    @Test
+    public void updateFileHandleTest() throws IOException {
+
+        File dir = new File(BASE_PKG + SLASH + TEST_FILE);
+        dir.mkdirs();
+        File createFile = new File(dir + TEST_FILE);
+        createFile.createNewFile();
+        File createSourceFile = new File(dir + SOURCE_TEST_FILE);
+        createSourceFile.createNewFile();
+        updateFileHandle(createFile, TEST_DATA_1, false);
+        updateFileHandle(createFile, TEST_DATA_2, false);
+        updateFileHandle(createFile, TEST_DATA_3, false);
+        appendFileContents(createFile, createSourceFile);
+        updateFileHandle(createFile, null, true);
+        deleteDirectory(dir);
+    }
+
+    /**
+     * This test  case checks whether the package is existing.
+     *
+     * @throws IOException when failed to create a test file
+     */
+    @Test
+    public void packageExistTest() throws IOException {
+
+        String strPath = BASE_DIR_PKG + DIR_PATH;
+        File createDir = new File(strPath.replace(PERIOD, SLASH));
+        createDir.mkdirs();
+        File createFile = new File(createDir + SLASH + PKG_INFO);
+        createFile.createNewFile();
+        assertThat(true, is(doesPackageExist(strPath)));
+        createPackage(getStubNode());
+        createDir.delete();
+        deleteDirectory(createDir);
+    }
+
+    /**
+     * Returns stub YANG node.
+     *
+     * @return stub node
+     */
+    private YangNode getStubNode() {
+        YangJavaModule module = new YangJavaModule();
+        module.setName(TEST_DATA_1);
+        JavaFileInfo javafileInfo = new JavaFileInfo();
+        javafileInfo.setJavaName(TEST_DATA_1);
+        javafileInfo.setBaseCodeGenPath("");
+        javafileInfo.setPackageFilePath(BASE_PKG);
+        javafileInfo.setPluginConfig(getStubPluginConfig());
+        module.setJavaFileInfo(javafileInfo);
+        return module;
+    }
+
+    /**
+     * Returns stub pluginConfig.
+     *
+     * @return stub pluginConfig
+     */
+    private YangPluginConfig getStubPluginConfig() {
+        YangPluginConfig pluginConfig = new YangPluginConfig();
+        pluginConfig.setConflictResolver(null);
+        return pluginConfig;
+    }
+
+}