*feature*

>Warning: A component is `contentEditable` and contains `children` managed by React. It is now your responsibility to guarantee that none of those nodes are unexpectedly modified or duplicated. This is probably not intentional.

It would help heaps if I would know _which_ component is causing this.
});
    it('gives source code refs for unknown prop warning for exact elements', () => {
      spyOn(console, 'error');
      ReactTestUtils.renderIntoDocument(
        <div className="foo1">
          <div class="foo2" />
          <div onClick={() => {}} />
          <div onclick={() => {}} />
          <div className="foo5" />
          <div className="foo6" />
        </div>,
      );
      expectDev(console.error.calls.count()).toBe(2);
      expectDev(console.error.calls.argsFor(0)[0]).toContain('className');
      var matches = console.error.calls.argsFor(0)[0].match(/.*\(.*:(\d+)\).*/);
      var previousLine = matches[1];
      expectDev(console.error.calls.argsFor(1)[0]).toContain('onClick');
      matches = console.error.calls.argsFor(1)[0].match(/.*\(.*:(\d+)\).*/);
      var currentLine = matches[1];
      
      
      expect(parseInt(previousLine, 10) + 2).toBe(parseInt(currentLine, 10));
    });
    it('gives source code refs for unknown prop warning for exact elements (ssr)', () => {
      spyOn(console, 'error');
      ReactDOMServer.renderToString(
        <div className="foo1">
          <div class="foo2" />
          <div onClick="foo3" />
          <div onclick="foo4" />