### Question:
CommonUtil { public static RegistryService getRegistryService() { return registryService; }  static synchronized void setRegistryService(RegistryService service); static RegistryService getRegistryService(); static void simulateRegistryOperation(Registry rootRegistry, SimulationRequest simulationRequest); static SimulationResponse getSimulationResponse(); static boolean updateHandler(Registry configSystemRegistry, String oldName, String payload); static boolean addHandler(Registry configSystemRegistry, String payload); static boolean handlerExists(Registry configSystemRegistry, String name); static boolean deleteHandler(Registry configSystemRegistry, String name); static String getHandlerConfiguration(Registry configSystemRegistry, String name); static String[] getHandlerList(Registry configSystemRegistry); static String getContextRoot(); static void setContextRoot(String contextRoot); static boolean generateHandler(Registry configSystemRegistry, String resourceFullPath); static boolean removeHandler(Registry configSystemRegistry, String handlerName); static boolean isHandlerNameInUse(String name); static boolean addDefaultHandlersIfNotAvailable(Registry configSystemRegistry); static SimulationService getSimulationService(); static void setSimulationService(SimulationService simulationService); static HandlerConfigurationBean deserializeHandlerConfiguration(OMElement configurationElement); static OMElement serializeHandlerConfiguration(HandlerConfigurationBean bean);  }### Answer:
@Test public void testGetRegistryService() throws Exception { RegistryService service = mock(RegistryService.class); CommonUtil.setRegistryService(service); assertEquals(service, CommonUtil.getRegistryService()); }