`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.

typeof inst.setState === 'function';
  },
  isCompositeComponentWithType: function(inst, type) {
    if (!ReactTestUtils.isCompositeComponent(inst)) {
      return false;
    }
    var internalInstance = ReactInstanceMap.get(inst);
    var constructor = internalInstance
      ._currentElement
      .type;
    return (constructor === type);
  },
  isCompositeComponentElement: function(inst) {
    if (!ReactElement.isValidElement(inst)) {
      return false;
    }
    
    
    var prototype = inst.type.prototype;
    return (
      typeof prototype.render === 'function' &&
      typeof prototype.setState === 'function'
    );
  },
  isCompositeComponentElementWithType: function(inst, type) {
    var internalInstance = ReactInstanceMap.get(inst);
    var constructor = internalInstance
      ._currentElement
      .type;
    return !!(ReactTestUtils.isCompositeComponentElement(inst) &&