Just about every time I set up a new `Context.Provider`, I end up accidentally specifying a `values` prop rather than `value`.  While it's a minor error, generally I build the container in which the provider resides and commit it to the code base before I ever use it.  It's only later when I go to use it that I realize I did it again.  Since the `Context.Provider` seems pretty much useless without a `value` prop specified, I'd love it if there was a prop error if it is missing... especially if another prop is defined on the `Context.Provider` instead.
],
    });
    renderer.update(
      <div>
        <span key="d">D</span>
        <span key="c">C</span>
        <span key="b">B</span>
      </div>,
    );
    expect(renderer.toJSON()).toEqual({
      type: 'div',
      props: {},
      children: [
        {type: 'span', props: {}, children: ['D']},
        {type: 'span', props: {}, children: ['C']},
        {type: 'span', props: {}, children: ['B']},
      ],
    });
  });
  it('does the full lifecycle', () => {
    const log = [];
    class Log extends React.Component {
      render() {
        log.push('render ' + this.props.name);
        return <div />;
      }
      componentDidMount() {
        log.push('mount ' + this.props.name);
      }
      componentWillUnmount() {