@Test
  public void startWithoutResponseHandler() throws InstantiationException {
    FrontendRestRequestService frontendRestRequestService =
        new FrontendRestRequestService(frontendConfig, frontendMetrics, router, clusterMap, idConverterFactory,
            securityServiceFactory, urlSigningService, idSigningService, null, accountService,
            accountAndContainerInjector, datacenterName, hostname, clusterName, accountStatsStore, QUOTA_MANAGER);
    try {
      frontendRestRequestService.start();
      fail("Test should fail if ResponseHandler is not setup");
    } catch (InstantiationException e) {
    }
    frontendRestRequestService.setupResponseHandler(responseHandler);
    frontendRestRequestService.start();
    frontendRestRequestService.shutdown();
  }
Start {@link FrontendRestRequestService} without {@link RestResponseHandler} should fail.
@throws InstantiationException
ambry-frontend/src/test/java/com/github/ambry/frontend/FrontendRestRequestServiceTest.java