anchor.diff:  /**
    * Allocate a Configuration. We allocate either a parent or child, depending on
    * whether the URL has a search part.
  - * 
  + *
    * Note: this unit test configuration will not work with the debugger (the tests
    * are executed in a separate IFrame).
    */
  
positive.code: final _singletonParent = new ParentInteractiveHtmlConfiguration();
  final _singletonChild = new ChildInteractiveHtmlConfiguration();
  
  String _CSS = """
  body {
  font-family: Arial, sans-serif;
  margin: 0;
  
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) {
  