Update App.test.js

Author: DEVUCP

front-end/src/App.test.js

@@ -3,6 +3,6 @@ import App from './App';
 
 test('renders learn react link', () => {
   render(<App />);
-  const linkElement = screen.getById("testApp");
+  const linkElement = screen.getByTestId('testApp');
   expect(linkElement).toBeInTheDocument();
 });