@Override
  protected Release findLatestActiveRelease(String configAppId, String configClusterName, String configNamespace,
                                            ApolloNotificationMessages clientMessages) {
    return releaseService.findLatestActiveRelease(configAppId, configClusterName,
        configNamespace);
  }
@Test
  public void testLoadConfigWithReleaseNotFound() throws Exception {
    when(releaseService.findLatestActiveRelease(someConfigAppId, someClusterName, defaultNamespaceName))
        .thenReturn(null);

    Release release = configService
        .loadConfig(someClientAppId, someClientIp, someClientLabel, someConfigAppId, someClusterName, defaultNamespaceName, someDataCenter,
            someNotificationMessages);

    assertNull(release);
  }