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 empty element when removing innerHTML', () => {
      var container = document.createElement('div');
      ReactDOM.render(
        <div dangerouslySetInnerHTML={{__html: ':)'}} />,
        container,
      );
      expect(container.firstChild.innerHTML).toEqual(':)');
      ReactDOM.render(<div />, container);
      expect(container.firstChild.innerHTML).toEqual('');
    });
    it('should transition from string content to innerHTML', () => {
      var container = document.createElement('div');
      ReactDOM.render(<div>hello</div>, container);
      expect(container.firstChild.innerHTML).toEqual('hello');
      ReactDOM.render(
        <div dangerouslySetInnerHTML={{__html: 'goodbye'}} />,
        container,
      );
      expect(container.firstChild.innerHTML).toEqual('goodbye');
    });
    it('should transition from innerHTML to string content', () => {
      var container = document.createElement('div');
      ReactDOM.render(
        <div dangerouslySetInnerHTML={{__html: 'bonjour'}} />,
        container,
      );
      expect(container.firstChild.innerHTML).toEqual('bonjour');
      ReactDOM.render(<div>adieu</div>, container);
      expect(container.firstChild.innerHTML).toEqual('adieu');