Added one mock unit test

src/App.vue

@@ -12,7 +12,7 @@
 
 <script>
 import HelloWorld from './components/HelloWorld.vue';
-import HeaderNav from './components/HeaderNav';
+import HeaderNav from '@/components/HeaderNav/HeaderNav.vue';
 import Colors from './components/Colors';
 
 export default {

src/components/HeaderNav/HeaderNav.spec.js

@@ -0,0 +1,7 @@
+describe("HeaderNav.vue", () => {
+
+    test("Some Example Test == True", () => {
+        expect(true).toBe(true);
+    });
+
+})