We used to throw if event listener is not a function in Stack:

```js
ReactDOM.render(
  <h1 onClick={{}}>Hello World!</h1>,
  document.getElementById('container')
);
```

<img width="565" alt="screen shot 2017-08-08 at 3 41 08 pm" src="https://user-images.githubusercontent.com/810438/29077502-2646412e-7c50-11e7-8c99-3b7f6c0a2589.png">

Fiber silently ignores this.

I think we should throw. This would let us add support for objects (e.g. for passive listener configuration) if we want to in a minor rather than a major.
});
    it('should transition from innerHTML to children in nested el', () => {
      var container = document.createElement('div');
      ReactDOM.render(
        <div><div dangerouslySetInnerHTML={{__html: 'bonjour'}} /></div>,
        container,
      );
      expect(container.textContent).toEqual('bonjour');
      ReactDOM.render(<div><div><span>adieu</span></div></div>, container);
      expect(container.textContent).toEqual('adieu');
    });
    it('should transition from children to innerHTML in nested el', () => {
      var container = document.createElement('div');
      ReactDOM.render(<div><div><span>adieu</span></div></div>, container);
      expect(container.textContent).toEqual('adieu');
      ReactDOM.render(
        <div><div dangerouslySetInnerHTML={{__html: 'bonjour'}} /></div>,
        container,
      );
      expect(container.textContent).toEqual('bonjour');
    });
    it('should not incur unnecessary DOM mutations for attributes', () => {
      var container = document.createElement('div');
      ReactDOM.render(<div id="" />, container);
      var node = container.firstChild;
      var nodeSetAttribute = node.setAttribute;
      node.setAttribute = jest.fn();
      node.setAttribute.mockImplementation(nodeSetAttribute);
      var nodeRemoveAttribute = node.removeAttribute;
      node.removeAttribute = jest.fn();