### Question:
SxpEpProviderProviderInstance implements SxpEpProviderProvider, ClusterSingletonService, AutoCloseable { public void initialize() { LOG.info("Clustering session initiated for {}", this.getClass().getSimpleName()); try { singletonServiceRegistration = clusterSingletonService.registerClusterSingletonService(this); } catch (Exception e) { LOG.warn("Exception thrown while registering cluster singleton service in {}", this.getClass(), e.getMessage()); } } SxpEpProviderProviderInstance(DataBroker dataBroker, BaseEndpointService endpointService,
                                         DomainSpecificRegistry registry,
                                         ClusterSingletonServiceProvider clusterSingletonService,
                                         SgtGeneratorConfig sgtGeneratorConfig); void initialize(); @Override void instantiateServiceInstance(); @Override ListenableFuture<Void> closeServiceInstance(); @Override void close(); @Override ServiceGroupIdentifier getIdentifier(); @Override EPToSgtMapper getEPToSgtMapper(); @Override EPPolicyTemplateProviderRegistry getEPPolicyTemplateProviderRegistry();  }### Answer:
@Test public void testInitialize() throws Exception { instance.initialize(); Mockito.verify(clusterSingletonService).registerClusterSingletonService(instance); }