anchor.diff:      bool enableObservatory: false,
       bool startPaused: false,
       int observatoryPort,
  +    int serverPort,
     }) {
       assert(executable != null); // Please provide the path to the shell in the SKY_SHELL environment variable.
       assert(!startPaused || enableObservatory);
  
positive.code: 
  void main() {
    print('$_kStartTimeoutTimerMessage');
    String server = Uri.decodeComponent('$encodedWebsocketUrl');
    StreamChannel channel = serializeSuite(() {
      catchIsolateErrors();
      return test.main;
  
negative.code:     listenerFile.createSync();
      listenerFile.writeAsStringSync(_generateTestMain(
        testUrl: fs.path.toUri(fs.path.absolute(testPath)).toString(),
        encodedWebsocketUrl: Uri.encodeComponent(_getWebSocketUrl()),
      ));
      return listenerFile.path;
    }
  