anchor.diff:  void _registerException(testNum, e, [trace]) {
     trace = trace == null ? '' : trace.toString();
     String message = (e is TestFailure) ? e.message : 'Caught $e';
  -  if (_testCases[testNum].result == null) {
  -    _testCases[testNum].fail(message, trace);
  +  if (testCases[testNum].result == null) {
  +    testCases[testNum].fail(message, trace);
     } else {
  -    _testCases[testNum].error(message, trace);
  +    testCases[testNum].error(message, trace);
     }
   }
   
  
positive.code: 
  /** Select a solo test by ID. */
  void setSoloTest(int id) {
    for (var i = 0; i < _testCases.length; i++) {
      if (_testCases[i].id == id) {
        _soloTest = _testCases[i];
        break;
      }
    }
  
negative.code:         this.id = _makeCallbackId(id, callback) {
      ensureInitialized();
      if (!(_currentTestCaseIndex >= 0 &&
             _currentTestCaseIndex < testCases.length &&
             testCases[_currentTestCaseIndex] != null)) {
        print("No valid test, did you forget to run your test inside a call "
            "to test()?");
      }
      assert(_currentTestCaseIndex >= 0 &&
             _currentTestCaseIndex < testCases.length &&
             testCases[_currentTestCaseIndex] != null);
      testCase = testCases[_currentTestCaseIndex];
      if (isDone != null || minExpected > 0) {
        testCase._callbackFunctionsOutstanding++;
        complete = false;
  