added some tests for main App.js

src/App.test.js

@@ -17,4 +17,62 @@ describe('<App/>', function () {
         const wrapper = shallow(<App/>);
         expect(wrapper.find('nav').find('li')).toHaveLength(4);
     });
+
+    it('simulate video view change ', function () {
+        const wrapper = shallow(<App/>);
+
+        wrapper.instance().showVideo(<div id='testit'></div>);
+
+        expect(wrapper.find("#testit")).toHaveLength(1);
+    });
+
+    it('test hide video again', function () {
+        const wrapper = shallow(<App/>);
+
+        wrapper.instance().showVideo(<div id='testit'></div>);
+
+        expect(wrapper.find("#testit")).toHaveLength(1);
+
+        wrapper.instance().hideVideo();
+
+        expect(wrapper.find("HomePage")).toHaveLength(1);
+    });
+
+    it('test fallback to last loaded page', function () {
+        const wrapper = shallow(<App/>);
+
+        wrapper.find(".nav-link").findWhere(t => t.text() === "Random Video" && t.type() === "div").simulate("click");
+
+        wrapper.instance().showVideo(<div id='testit'></div>);
+
+        expect(wrapper.find("#testit")).toHaveLength(1);
+
+        wrapper.instance().hideVideo();
+
+        expect(wrapper.find("RandomPage")).toHaveLength(1);
+    });
+
+    it('test home click', function () {
+        const wrapper = shallow(<App/>);
+        wrapper.setState({page: "wrongvalue"});
+        expect(wrapper.find("HomePage")).toHaveLength(0);
+        wrapper.find(".nav-link").findWhere(t => t.text() === "Home" && t.type() === "div").simulate("click");
+        expect(wrapper.find("HomePage")).toHaveLength(1);
+    });
+
+    it('test category click', function () {
+        const wrapper = shallow(<App/>);
+
+        expect(wrapper.find("CategoryPage")).toHaveLength(0);
+        wrapper.find(".nav-link").findWhere(t => t.text() === "Categories" && t.type() === "div").simulate("click");
+        expect(wrapper.find("CategoryPage")).toHaveLength(1);
+    });
+
+    it('test settings click', function () {
+        const wrapper = shallow(<App/>);
+
+        expect(wrapper.find("SettingsPage")).toHaveLength(0);
+        wrapper.find(".nav-link").findWhere(t => t.text() === "Settings" && t.type() === "div").simulate("click");
+        expect(wrapper.find("SettingsPage")).toHaveLength(1);
+    });
 });