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.
expect(render.root.parent).toBe(null);
    expect(foo.children[0].parent).toBe(foo);
  });
  it('searches via .find() / .findAll()', () => {
    const render = ReactTestRenderer.create(<Example />);
    const hasFooProp = node => node.props.hasOwnProperty('foo');
    const hasBarProp = node => node.props.hasOwnProperty('bar');
    const hasBazProp = node => node.props.hasOwnProperty('baz');
    const hasBingProp = node => node.props.hasOwnProperty('bing');
    const hasNullProp = node => node.props.hasOwnProperty('null');
    const hasVoidProp = node => node.props.hasOwnProperty('void');
    const hasItselfProp = node => node.props.hasOwnProperty('itself');
    const hasNestedProp = node => node.props.hasOwnProperty('nested');
    expect(() => render.root.find(hasFooProp)).not.toThrow(); 
    expect(() => render.root.find(hasBarProp)).toThrow(); 
    expect(() => render.root.find(hasBazProp)).toThrow(); 
    expect(() => render.root.find(hasBingProp)).not.toThrow(); 
    expect(() => render.root.find(hasNullProp)).not.toThrow(); 
    expect(() => render.root.find(hasVoidProp)).toThrow(); 
    expect(() => render.root.find(hasNestedProp)).toThrow(); 
    
    expect(render.root.findAll(hasFooProp, {deep: false})).toHaveLength(1);
    expect(render.root.findAll(hasBarProp, {deep: false})).toHaveLength(5);
    expect(render.root.findAll(hasBazProp, {deep: false})).toHaveLength(2);
    expect(render.root.findAll(hasBingProp, {deep: false})).toHaveLength(1);
    expect(render.root.findAll(hasNullProp, {deep: false})).toHaveLength(1);
    expect(render.root.findAll(hasVoidProp, {deep: false})).toHaveLength(0);
    expect(render.root.findAll(hasNestedProp, {deep: false})).toHaveLength(3);