@Override
          public void testAndAssert(RouterErrorCode expectedError) throws Exception {
            CountDownLatch operationCompleteLatch = new CountDownLatch(1);
            future =
                router.deleteBlob(null, blobIdString, null, new ClientCallback(operationCompleteLatch), quotaChargeCallback);
            do {
              // increment mock time
              mockTime.sleep(1000);
            } while (!operationCompleteLatch.await(10, TimeUnit.MILLISECONDS));
            assertFailureAndCheckErrorCode(future, expectedError);
          }
Test the case when request gets expired before the corresponding store server sends
back a response. Set servers to not respond any requests, so {@link DeleteOperation}
can be "in flight" all the time. The order of received responses is the same as defined
in {@code serverErrorCodes}.
ambry-router/src/test/java/com/github/ambry/router/DeleteManagerTest.java