30DaysOfTDD_Day21_Part2

        private Dictionary<Guid, int> CheckInventoryLevels(ShoppingCart shoppingCart, Guid orderFulfillmentSessionId)
        {
            var orderForFulfillmentService = new Dictionary<Guid, int>();

            foreach (var shoppingCartItem in shoppingCart.Items)
            {
                var itemId = shoppingCartItem.ItemId;
                var itemQuantity = shoppingCartItem.Quantity;

                var itemIsInInventory = _orderFulfillmentService.IsInInventory(orderFulfillmentSessionId, itemId, itemQuantity);

                orderForFulfillmentService.Add(itemId, itemQuantity);
            }
            return orderForFulfillmentService;
        }