anchor.diff:      } else if (res.errors.isNotEmpty) {
         print(testFile);
         print(res.errors);
  -
       }
     })..onError((error) => res.errors.add(error));
   
  
positive.code:     if (seenTests == fileCount) {
        resultStream.close();
      }
  
    }).onDone(endRun);
  
    return testCompleter.future;
  }
  
  
  String summary(Result res) =>
      'processing speed: ${(res.byteCount~/res.runtime.inMilliseconds)/1000}MiB/s\n'
          'total packets:${res.packetCount}\n'
          'total running time (msec):${res.runtime.inMilliseconds}\n'
          'bytes processed:${res.byteCount}\n' 'number of errors:${res.errors.length}\n'
          'errors:\n'
          '${res.errors.fold('', (buf, error) => buf + error.toString() + '\n')}';
  
  
  void testFile(IO.File testFile, StreamController<Result> resultStream,
      {bool shouldFail: false}) {
  
negative.code: 
    String toString() =>
        '${file}\tpackets:${packetCount}' '\tmsec:${runtime.inMilliseconds}'
        '\tbytes:${byteCount}' '\terrors:${errors.length}';
  }
  
  List l = [];
  var ost = l.join('2');
  
  Future<bool> packet_transformer() {
    String testDataPath = './test_data/';
  