public void subscribeRegistryConfig(String serviceName) {
        ConfigSubscriber subscriber;
        final RegisterConfig registerConfig = PluginConfigManager.getPluginConfig(RegisterConfig.class);
        final RegisterServiceCommonConfig registerCommonConfig =
                PluginConfigManager.getPluginConfig(RegisterServiceCommonConfig.class);
        if (registerCommonConfig.getRegisterType() == RegisterType.SERVICE_COMB
                && registerConfig.isEnableSpringRegister()) {
            // CSE was used
            subscriber = new CseGroupConfigSubscriber(serviceName, new RegistryConfigListener(),
                    "SpringCloudRegistry");
        } else {
            // Other scenarios
            subscriber = new DefaultGroupConfigSubscriber(serviceName, new RegistryConfigListener(),
                    "SpringCloudRegistry");
        }
        subscriber.subscribe();
        fixGrace();
    }
@Test
    public void subscribeRegistryConfig() {
        final RegistryConfigSubscribeServiceImpl mock = Mockito.mock(RegistryConfigSubscribeServiceImpl.class);
        String serviceName = "test";
        mock.subscribeRegistryConfig(serviceName);
        Mockito.verify(mock, Mockito.times(1)).subscribeRegistryConfig(serviceName);
    }