VCST-661: The effect off X cart subtotal, no more than Y does not tak…

…e an account the selected items in cart (#544)

fix: The effect off X cart subtotal, no more than Y does not take an account the selected items in cart.

src/XPurchase/VirtoCommerce.XPurchase/Extensions/RewardExtensions.cs

@@ -60,7 +60,7 @@ public static void ApplyRewards(this CartAggregate aggregate, ICollection<Promot
                 payment.ApplyRewards(shoppingCart.Currency, paymentRewards);
             }
 
-            var subTotalExcludeDiscount = shoppingCart.Items.Sum(li => (li.ListPrice - li.DiscountAmount) * li.Quantity);
+            var subTotalExcludeDiscount = shoppingCart.Items.Where(li => li.SelectedForCheckout).Sum(li => (li.ListPrice - li.DiscountAmount) * li.Quantity);
 
             var cartRewards = rewards.OfType<CartSubtotalReward>();
             foreach (var reward in cartRewards.Where(reward => reward.IsValid))