anchor.diff:    bool run() {
       setup();
   
  -    print('\nRun isolate: ${runner1.description} vs. '
  -        '${runner2.description} in ${tmpDir.path}');
  -
  +    print('\n${isolate}: start');
       if (showStats) {
         showStatistics();
       }
  +
       for (int i = 0; i < repeat; i++) {
         numTests++;
         seed = rand.nextInt(1 << 32);
  
positive.code:       runTest();
        if (showStats) {
          showStatistics();
        }
      }
  
      print('\nDone isolate: ${runner1.description} vs. '
          '${runner2.description} in ${tmpDir.path}');
      showStatistics();
      print('');
  
  
negative.code:   String fileName;
    TestRunner runner1;
    TestRunner runner2;
    String isolate;
    int seed;
  
    // Stats.
  