### Question:
ClusterControllerImpl implements ClusterController { @Override public void stop() { this.controllerLeaderSelector.close(); } ClusterControllerImpl(ClusterMetadataStore clusterMetadataStore,
                                 RegistrationClient registrationClient,
                                 StorageContainerController scController,
                                 ClusterControllerLeaderSelector clusterControllerLeaderSelector,
                                 StorageConfiguration conf); @Override void start(); @Override void stop();  }### Answer:
@Test public void testStop() { service.start(); service.stop(); verify(leaderSelector, times(1)).close(); }