I think this shouldn't pass:

```js
    expect(() => {
      expect(() => {
        throw new Error('haha') // no warning
      }).toWarnDev(
        'nope',
      );
    }).toThrow('haha');
```

but it does.
constructor(props) {
        const _props = {idx: props.idx + '!'};
        super(_props);
      }
      render() {
        return <span />;
      }
    }
    expect(() => ReactDOM.render(<Foo idx="qwe" />, container)).toWarnDev(
      'Foo(...): When calling super() in `Foo`, make sure to pass ' +
        "up the same props that your component's constructor was passed.",
      {withoutStack: true},
    );
  });
  it('should only call componentWillUnmount once', () => {
    let app;
    let count = 0;
    class App extends React.Component {
      render() {
        if (this.props.stage === 1) {
          return <UnunmountableComponent />;
        } else {
          return null;
        }
      }
    }
    class UnunmountableComponent extends React.Component {