private void routerFailureTest() throws Exception {
    // get the router to throw a RuntimeException
    Properties properties = new Properties();
    properties.setProperty(InMemoryRouter.OPERATION_THROW_EARLY_RUNTIME_EXCEPTION, "true");
    router.setVerifiableProperties(new VerifiableProperties(properties));
    verifyFailureWithMsg(InMemoryRouter.OPERATION_THROW_EARLY_RUNTIME_EXCEPTION);

    // get the router to return a RuntimeException
    properties = new Properties();
    properties.setProperty(InMemoryRouter.OPERATION_THROW_LATE_RUNTIME_EXCEPTION, "true");
    router.setVerifiableProperties(new VerifiableProperties(properties));
    verifyFailureWithMsg(InMemoryRouter.OPERATION_THROW_LATE_RUNTIME_EXCEPTION);

    router.setVerifiableProperties(new VerifiableProperties(new Properties()));
  }
Tests the case where the {@link com.github.ambry.router.Router} fails or returns an exception
@throws Exception
ambry-frontend/src/test/java/com/github/ambry/frontend/TtlUpdateHandlerTest.java