anchor.diff:   * IFrame, so the configuration consists of two parts - a 'parent'
    * config that manages all the tests, and a 'child' config for the
    * IFrame that runs the individual tests.
  - * 
  + *
    * Note: this unit test configuration will not work with the debugger (the tests
    * are executed in a separate IFrame).
    */
  
positive.code:     window.onMessage.listen((MessageEvent e) {
        // Get the result, do any logging, then do a pass/fail.
        var m = new _Message.fromString(e.data);
        if (m.messageType == _Message.START) {
          parentWindow = e.source;
          String search = window.location.search;
          int pos = search.indexOf('t=');
          String ids = search.substring(pos+2);
  
negative.code:   void _handleMessage(MessageEvent e) {
      // Get the result, do any logging, then do a pass/fail.
      var msg = new _Message.fromString(e.data);
  
      if(msg == null) {
        return;
      }
      if (msg.messageType == _Message.LOG) {
        logMessage(e.data);
      } else if (msg.messageType == _Message.STACK) {
  