### Question:
ActiveRotationRegistry { public void refreshFileHandles() { registeredInstances.forEach(ActiveRotationRegistry::safelyCallPostRotate); }  static ActiveRotationRegistry getSingletonInstance(); static void setSingletonInstance(ActiveRotationRegistry newRegistry); T add(T instance); void remove(ActiveRotationSupport instance); boolean contains(ActiveRotationSupport instance); void refreshFileHandles();  }### Answer:
@Test public void refreshFileHandles_shouldNotRefreshFileHandlesOnAnInstanceThatHasNotBeenAdded() throws Exception { ActiveRotationSupport ars = mock(ActiveRotationSupport.class); registry.refreshFileHandles(); verifyZeroInteractions(ars); }