public abstract SubClusterId getApplicationHomeSubCluster(ApplicationId appId) throws Exception;
@Test
  public void testGetHomeSubClusterForApp() throws YarnException {
    for (int i = 0; i < numApps; i++) {
      ApplicationId appId = ApplicationId.newInstance(clusterTs, i);
      SubClusterId expectedSC = stateStoreTestUtil.queryApplicationHomeSC(appId);
      SubClusterId cachedPC = facade.getApplicationHomeSubCluster(appId);
      assertEquals(expectedSC, cachedPC);
    }
  }