### Question:
ClusterProxyService { public void deregisterCluster(Stack stack) { stackUpdater.updateClusterProxyRegisteredFlag(stack, false); clusterProxyRegistrationClient.deregisterConfig(stack.getResourceCrn()); }  ConfigRegistrationResponse registerCluster(Stack stack); ConfigRegistrationResponse reRegisterCluster(Stack stack); void registerGatewayConfiguration(Long stackId); boolean useClusterProxyForCommunication(Tunnel tunnel, String cloudPlatform); boolean useClusterProxyForCommunication(Stack stack); boolean isCreateConfigForClusterProxy(Stack stack); void deregisterCluster(Stack stack); String getProxyPath(String crn); com.sequenceiq.cloudbreak.api.endpoint.v4.autoscales.response.ClusterProxyConfiguration getClusterProxyConfigurationForAutoscale(); static final String CB_INTERNAL; }### Answer:
@Test public void shouldDeregisterCluster() throws ClusterProxyException { service.deregisterCluster(testStack()); verify(clusterProxyRegistrationClient).deregisterConfig(STACK_CRN); }