anchor.diff:        var stopwatch = new Stopwatch()..start();
   
         // Initialize query specific objects
  -      TestMapper mapper = new TestMapper(new CompletionMapper(), file.path);
  +      TestMapper mapper = new TestMapper(new SevereLogMapper(), file.path);
   
         // Extraction
         await mapper.init({}, (String key, value) {
  
positive.code:   if (io.FileSystemEntity.isDirectorySync(path)) {
      files = new io.Directory(path).listSync().where((file) {
        var name = basename(file.path);
        return name.startsWith('compressed-') && name.endsWith('.json');
      }).toList();
    } else {
      files = [new io.File(path)];
  
negative.code:           .openRead()
            .transform(UTF8.decoder)
            .transform(new LineSplitter())
            .transform(new LogItemTransformer(allowNonSequentialMsgs: true))
            .handleError((e, s) {
          ++mapper.readFailureCount;
          print("Error reading line\n${trim300(e.toString())}\n$s");
  