Type check test files

Created by: affanshahid

Bug report

I created a new project with the --typescript flag, and added a type for my component's props like so:

type AppProps = {
  name: string
};

class App extends Component<AppProps> {
  render() {
    return (
      ...
    );
  }
}

In index.tsx when I write something like (note the missing prop):

ReactDOM.render(<App />, document.getElementById('root')); // name prop is missing

I get an error in both my editor (VSCode) and on my console when I run yarn start.

However in my tests if I have something like:

it('renders without crashing', () => {
  const div = document.createElement('div');
  ReactDOM.render(<App />, div);
  ReactDOM.unmountComponentAtNode(div);
});

I get the type error in my editor but NOT when I run yarn test, the tests run successfully in fact.

Is this intended?