`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.

'for class:' + className
      );
    }
    return all[0];
  },
  /**
   * Finds all instance of components in the rendered tree that are DOM
   * components with the tag name matching `tagName`.
   * @return {array} an array of all the matches.
   */
  scryRenderedDOMComponentsWithTag: function(root, tagName) {
    return ReactTestUtils.findAllInRenderedTree(root, function(inst) {
      return ReactTestUtils.isDOMComponent(inst) &&
            inst.tagName.toUpperCase() === tagName.toUpperCase();
    });
  },
  /**
   * Like scryRenderedDOMComponentsWithTag but expects there to be one result,
   * and returns that one result, or throws exception if there is any other
   * number of matches besides one.
   * @return {!ReactDOMComponent} The one match.
   */
  findRenderedDOMComponentWithTag: function(root, tagName) {
    var all = ReactTestUtils.scryRenderedDOMComponentsWithTag(root, tagName);
    if (all.length !== 1) {
      throw new Error(
        'Did not find exactly one match (found: ' + all.length + ') ' +
        'for tag:' + tagName
      );
    }