### Question:
ActiveRotationRegistry { public void remove(ActiveRotationSupport instance) { registeredInstances.remove(instance); }  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 remove_shouldNotComplain_givenAnUnregisteredInstance() throws Exception { ActiveRotationSupport ars = mock(ActiveRotationSupport.class); registry.remove(ars); }