`SyntheticEvent.type` is undefined when received by the handler. Or the nativeEvent type for that matter.

Needs to be added in here somewhere: https://github.com/facebook/react/blob/3a4e1dbb5b2957875cab6af11a5e5934e125a0d8/src/test/ReactTestUtils.js#L496

I realize that it's not sustainable to have to set _all_ the possible fields for a simulated event, but the type at least makes sense for verification that you're getting the right _sort_ of event.

return ReactDOM.render(instance, div);
  },
  isElement: function(element) {
    return ReactElement.isValidElement(element);
  },
  isElementOfType: function(inst, convenienceConstructor) {
    return (
      ReactElement.isValidElement(inst) &&
      inst.type === convenienceConstructor
    );
  },
  isDOMComponent: function(inst) {
    return !!(inst && inst.nodeType === 1 && inst.tagName);
  },
  isDOMComponentElement: function(inst) {
    return !!(inst &&
              ReactElement.isValidElement(inst) &&
              !!inst.tagName);
  },
  isCompositeComponent: function(inst) {
    if (ReactTestUtils.isDOMComponent(inst)) {
      
      
      return false;
    }
    return inst != null &&
           typeof inst.render === 'function' &&