anchor.diff:        break;
       }
       final testCase = _tests[_currentTest];
  -    var f = guardAsync(testCase.run, null, _currentTest);
  +    var f = _guardAsync(testCase.run, null, _currentTest);
       if (f != null) {
         f.whenComplete(() {
           _nextTestCase(); // Schedule the next test.
  
positive.code:  *
   * The value returned by [tryBody] (if any) is returned by [guardAsync].
   */
  guardAsync(Function tryBody, [Function finallyBody, int testNum = -1]) {
    if (testNum < 0) testNum = _currentTest;
    try {
      return tryBody();
    } catch (e, trace) {
  
negative.code:   }
  
    invoke1(arg1) {
      return _guardAsync(
          () {
            if (shouldCallBack()) {
              return callback(arg1);
  