Q:

Trouble-shooting a basic test with React and Jest

I have setup a basic test with React and Jest. It seems to be failing for some reason.
import React from 'react';
import ReactDOM from 'react-dom';
import TestUtils from 'react-addons-test-utils';
// import App from '../src/client/app.jsx';

const App = (props) => (
  <div>Hello world</div>
);

it('App renders hello world', () => {
  const app1 = TestUtils.renderIntoDocument(<App />);
  const appNode = ReactDOM.findDOMNode(app1);
  console.log(app1, appNode);
  expect(appNode.textContent).toEqual('Hello world');
});

Both app1 and appNode are null when printed to the console. Any help?
Screenshot below:

A:

TestUtils and React Stateless Components:

the suggested solution is to wrap the component inside of another
  component such as a DIV.

const app1 = TestUtils.renderIntoDocument(<div><App /></div>); // this should work

