@Override
  public List<ServiceDTO> getServiceInstances(String serviceId) {
    String configName = SERVICE_ID_TO_CONFIG_NAME.get(serviceId);
    if (configName == null) {
      return Collections.emptyList();
    }

    return assembleServiceDTO(serviceId, bizConfig.getValue(configName));
  }
@Test
  public void testGetServiceInstancesWithNullConfig() {
    when(bizConfig.getValue(configServiceConfigName)).thenReturn(null);

    assertTrue(
        kubernetesDiscoveryService.getServiceInstances(ServiceNameConsts.APOLLO_CONFIGSERVICE)
            .isEmpty());

    verify(bizConfig, times(1)).getValue(configServiceConfigName);
  }