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.

mountComponent({dangerouslySetInnerHTML: {foo: 'bar'} });
      }).toThrowError(
        '`props.dangerouslySetInnerHTML` must be in the form `{__html: ...}`. ' +
        'Please visit https://fb.me/react-invariant-dangerously-set-inner-html for more information.'
      );
    });
    it('should allow {__html: null}', function() {
      expect(function() {
        mountComponent({dangerouslySetInnerHTML: {__html: null} });
      }).not.toThrow();
    });
    it('should warn about contentEditable and children', function() {
      spyOn(console, 'error');
      mountComponent({contentEditable: true, children: ''});
      expect(console.error.calls.count()).toBe(1);
      expect(console.error.calls.argsFor(0)[0]).toContain('contentEditable');
    });
    it('should respect suppressContentEditableWarning', function() {
      spyOn(console, 'error');
      mountComponent({contentEditable: true, children: '', suppressContentEditableWarning: true});
      expect(console.error.calls.count()).toBe(0);
    });
    it('should validate against invalid styles', function() {
      expect(function() {
        mountComponent({style: 'display: none'});
      }).toThrowError(
        'The `style` prop expects a mapping from style properties to values, ' +
        'not a string. For example, style={{marginRight: spacing + \'em\'}} ' +
        'when using JSX.'
      );