The error event on `<source>` elements doesn't work. Looking at #4370, it seems like there is an `onError` for `<video>` but I can't tell if that's supposed to work for `<source>` too.

The error event is useful so I can deduce which format the browser is using.

);
    });
    it('should warn against dangerouslySetInnerHTML for void elements', function() {
      ReactDOM.render(<input />, container);
      expect(function() {
        ReactDOM.render(
          <input dangerouslySetInnerHTML={{__html: 'content'}} />,
          container
        );
      }).toThrowError(
        'input is a void element tag and must not have `children` or use ' +
        '`props.dangerouslySetInnerHTML`.'
      );
    });
    it('should validate against multiple children props', function() {
      ReactDOM.render(<div></div>, container);
      expect(function() {
        ReactDOM.render(
          <div children="" dangerouslySetInnerHTML={{__html: ''}}></div>,
          container
        );
      }).toThrowError(
        'Can only set one of `children` or `props.dangerouslySetInnerHTML`.'
      );
    });
    it('should warn about contentEditable and children', function() {
      spyOn(console, 'error');
      ReactDOM.render(
        <div contentEditable={true}><div /></div>,
        container