*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.
expectDev(console.error.calls.argsFor(0)[0]).toContain(
        'Warning: Invalid DOM property `cLASS`. Did you mean `className`?',
      );
    });
    it('sets aliased attributes on SVG elements with a warning', function() {
      spyOn(console, 'error');
      var el = ReactTestUtils.renderIntoDocument(
        <svg><text arabic-form="initial" /></svg>,
      );
      var text = el.querySelector('text');
      expect(text.hasAttribute('arabic-form')).toBe(true);
      expectDev(console.error.calls.argsFor(0)[0]).toContain(
        'Warning: Invalid DOM property `arabic-form`. Did you mean `arabicForm`?',
      );
    });
    it('sets aliased attributes on custom elements', function() {
      var el = ReactTestUtils.renderIntoDocument(
        <div is="custom-element" class="test" />,
      );
      expect(el.getAttribute('class')).toBe('test');
    });
    it('aliased attributes on custom elements with bad casing', function() {
      var el = ReactTestUtils.renderIntoDocument(
        <div is="custom-element" claSS="test" />,
      );
      expect(el.getAttribute('class')).toBe('test');
    });
    it('updates aliased attributes on custom elements', function() {
      var container = document.createElement('div');
      ReactDOM.render(<div is="custom-element" class="foo" />, container);