### Question:
ActiveRotationRegistry { public boolean contains(ActiveRotationSupport instance) { return registeredInstances.contains(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 contains_shouldReturnFalse_givenAnInstanceThatHasNotBeenAdded() throws Exception { ActiveRotationSupport ars = mock(ActiveRotationSupport.class); assertFalse(registry.contains(ars)); }