public abstract FetchedAppReport getApplicationReport(ApplicationId appId)
      throws YarnException, IOException;
@Test
  void testFetchReportAHSDisabled() throws YarnException, IOException {
    try {
      testHelper(false);
    } catch (ApplicationNotFoundException e) {
      assertEquals(appNotFoundExceptionMsg, e.getMessage());
      /* RM will not know of the app and Application History Service is disabled
       * So we will not try to get the report from AHS and RM will throw
       * ApplicationNotFoundException
       */
    }
    Mockito.verify(appManager, Mockito.times(1))
        .getApplicationReport(Mockito.any(GetApplicationReportRequest.class));
    if (historyManager != null) {
      fail("HistoryManager should be null as AHS is disabled");
    }
  }