anchor.diff:        tempDir = new Directory(tempDirPath);
         if (!tempDir.existsSync()) {
           tempDir.createSync();
  -      }      
  +      }
       }
       tempDirPath = new File(tempDirPath).fullPathSync();
   
  
positive.code:     if (new Platform().operatingSystem() == 'macos') {
        return 'client/tests/drt/DumpRenderTree.app/Contents/' +
            'MacOS/DumpRenderTree';
      } 
      return 'client/tests/drt/DumpRenderTree';
    }
  
  
negative.code:           RandomAccessFile dartLibrary = file.openSync(FileMode.WRITE);
            dartLibrary.writeStringSync(WrapDartTestInLibrary(testPath));
            dartLibrary.closeSync();
          }
  
          File file = new File(dartWrapperFilename);
          RandomAccessFile dartWrapper = file.openSync(FileMode.WRITE);
          dartWrapper.writeStringSync(DartTestWrapper(
  