anchor.diff:  class _FailingTest {
     const _FailingTest();
   }
  +
  +/**
  + * A marker annotation used to annotate a test class to run it using
  + * [solo_group].
  + */
  +class _SoloTest {
  +  const _SoloTest();
  +}
  
positive.code:  * for the annotated classes.
   */
  const ReflectiveTest reflectiveTest = const ReflectiveTest();
  
  /**
   * Is `true` the application is running in the checked mode.
  
negative.code:     throw new Exception('Class $name must have annotation "@reflectiveTest" '
          'in order to be run by runReflectiveTests.');
    }
    void runMembers() {
      classMirror.instanceMembers
          .forEach((Symbol symbol, MethodMirror memberMirror) {
        // we need only methods
  