anchor.diff:   * case it must return a [Future].
    */
   void setUp(Function setupTest) {
  +  _requireNotRunning();
     _testSetup = setupTest;
   }
   
  
positive.code:   final int minExpectedCalls;
    final int maxExpectedCalls;
    final Function isDone;
    final int testNum;
    final String id;
    int actualCalls = 0;
    TestCase testCase;
    bool complete;
    static const sentinel = const _Sentinel();
  
  
negative.code: /** Teardown function called after each test in a group */
  Function _testTeardown;
  
  TestCase _currentTestCase = null;
  
  /** [TestCase] currently being executed. */
  TestCase get currentTestCase => _currentTestCase;
  
  /** Whether the framework is in an initialized state. */
  bool _initialized = false;
  