public void Holds_Test(RealTimeInventory inventory, int toHold)
        {
            IInventoryServiceCompletedMessage response;

            using (var testHelper = CreateInventoryServiceServer(inventory))
                response = testHelper.PlaceHoldAsync(inventory, toHold).WaitAndGetOperationResult();

            InventoryServiceSpecificationHelper.AssertHolds(inventory, toHold, response);
        }