super();
        this.state = {active: false};
        barInstances.push(this);
      }
      activate() {
        this.setState({active: true});
      }
      render() {
        ops.push('Bar');
        return <span prop={this.state.active ? 'X' : this.props.idx} />;
      }
    }
    function Foo(props) {
      ops.push('Foo');
      return (
        <div>
          <span prop={props.tick} />
          <div hidden={true}>
            <Bar idx={props.idx} />
            <Bar idx={props.idx} />
            <Bar idx={props.idx} />
          </div>
        </div>
      );
    }
    ReactNoop.render(<Foo tick={0} idx={0} />);
    ReactNoop.flush();
    expect(ReactNoop.getChildren()).toEqual([
      div(span(0), div(span(0), span(0), span(0))),
    ]);