constructor() {
        super();
        instance = this;
        this.state = {text: 'foo'};
      }
      render() {
        return <span prop={this.state.text} />;
      }
    }
    ReactNoop.render(<Foo />);
    ReactNoop.flush();
    expect(ReactNoop.getChildren()).toEqual([span('foo')]);
    let called = false;
    instance.setState({text: 'bar'}, () => {
      expect(ReactNoop.getChildren()).toEqual([span('bar')]);
      called = true;
    });
    ReactNoop.flush();
    expect(called).toBe(true);
  });
  it('calls setState callback even if component bails out', () => {
    let instance;
    class Foo extends React.Component {
      constructor() {
        super();
        instance = this;
        this.state = {text: 'foo'};
      }
      shouldComponentUpdate(nextProps, nextState) {