*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('should warn about incorrect casing on event handlers (ssr)', () => {
      spyOn(console, 'error');
      ReactDOMServer.renderToString(
        React.createElement('input', {type: 'text', onclick: '1'}),
      );
      ReactDOMServer.renderToString(
        React.createElement('input', {type: 'text', onKeydown: '1'}),
      );
      expectDev(console.error.calls.count()).toBe(2);
      expectDev(console.error.calls.argsFor(0)[0]).toContain('onClick');
      expectDev(console.error.calls.argsFor(1)[0]).toContain('onKeyDown');
    });
    it('should warn about incorrect casing on properties', () => {
      spyOn(console, 'error');
      ReactTestUtils.renderIntoDocument(
        React.createElement('input', {type: 'text', tabindex: '1'}),
      );
      expectDev(console.error.calls.count()).toBe(1);
      expectDev(console.error.calls.argsFor(0)[0]).toContain('tabIndex');
    });
    it('should warn about incorrect casing on event handlers', () => {
      spyOn(console, 'error');
      ReactTestUtils.renderIntoDocument(
        React.createElement('input', {type: 'text', onclick: '1'}),
      );
      ReactTestUtils.renderIntoDocument(
        React.createElement('input', {type: 'text', onKeydown: '1'}),
      );
      expectDev(console.error.calls.count()).toBe(2);
      expectDev(console.error.calls.argsFor(0)[0]).toContain('onClick');