test: Add spec for VTag that router is called

This is linked to gothinkster#195

tests/unit/components/VTag.spec.js

@@ -0,0 +1,25 @@
+import { mount, createLocalVue } from "@vue/test-utils";
+
+import router from "../../../src/router/index";
+import VTag from "../../../src/components/VTag";
+
+const localVue = createLocalVue();
+const createWrapper = () => {
+  return mount(VTag, {
+    localVue,
+    router,
+    propsData: {
+      name: "Foo"
+    }
+  });
+};
+
+describe("VTag", () => {
+  it("should update the route on click", async () => {
+    const wrapper = createWrapper();
+    const routerBefore = wrapper.vm.$route.path;
+    wrapper.find("a").trigger("click");
+    await localVue.nextTick();
+    expect(wrapper.vm.$route.path).not.toBe(routerBefore);
+  });
+});