*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.
expect(node.removeAttribute.mock.calls.length).toBe(2);
    });
    it('should not incur unnecessary DOM mutations for string properties', () => {
      var container = document.createElement('div');
      ReactDOM.render(<div value="" />, container);
      var node = container.firstChild;
      var nodeValueSetter = jest.genMockFn();
      var oldSetAttribute = node.setAttribute.bind(node);
      node.setAttribute = function(key, value) {
        oldSetAttribute(key, value);
        nodeValueSetter(key, value);
      };
      ReactDOM.render(<div value="foo" />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(1);
      ReactDOM.render(<div value="foo" />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(1);
      ReactDOM.render(<div />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(1);
      ReactDOM.render(<div value={null} />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(1);
      ReactDOM.render(<div value="" />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(2);
      ReactDOM.render(<div />, container);
      expect(nodeValueSetter.mock.calls.length).toBe(2);
    });
    it('should not incur unnecessary DOM mutations for boolean properties', () => {
      var container = document.createElement('div');
      ReactDOM.render(<div checked={true} />, container);
      var node = container.firstChild;
      var nodeValue = true;