anchor.diff:    _ensureInitialized(true);
   }
   
  -void _requireNotRunning() {
  -  if(_currentTestCase != null) {
  -    throw new StateError("A forbidden operation occured "
  -        "while tests were running");
  -  }
  -}
  -
   void _ensureInitialized(bool configAutoStart) {
  -  _requireNotRunning();
     if (_initialized) {
       return;
     }
  
positive.code:             ? minExpected
              : maxExpected,
          this.isDone = isDone,
          this.testCase = currentTestCase,
          this.id = _makeCallbackId(id, callback) {
      if(testCase == null) {
        throw new StateError("No valid test, did you forget to run your test "
            "inside a call to test()?");
      }
  
      if (isDone != null || minExpected > 0) {
        testCase._callbackFunctionsOutstanding++;
        complete = false;
  
negative.code: /** Teardown function called after each test in a group */
  Function _testTeardown;
  
  int _currentTestCaseIndex = 0;
  
  /** [TestCase] currently being executed. */
  TestCase get currentTestCase =>
      (_currentTestCaseIndex >= 0 && _currentTestCaseIndex < testCases.length)
          ? testCases[_currentTestCaseIndex]
          : null;
  
  /** Whether the framework is in an initialized state. */
  bool _initialized = false;
  