anchor.diff:            ++_callbackFunctionsOutstanding;
             return testFunction();
           })
  -        .catchError(errorHandler('Test'))
  +        .catchError(_errorHandler('Test'))
           .then((_) {
             _markCallbackComplete();
             if (result == null) {
  
positive.code:     _message = '';
  
      var f = (setUp == null) ? new Future.value() : new Future(setUp);
      return f.catchError(errorHandler('Setup'))
          .then((_) {
            // Skip the test if setup failed.
            if (result != null) return new Future.value();
  
negative.code: 
    bool get isComplete => !enabled || result != null;
  
    Function _errorHandler(String stage) => (e) {
      var stack = getAttachedStackTrace(e);
      if (result == null || result == PASS) {
        if (e is TestFailure) {
  