Adding Tests and Refactoring

Functional Tests for RazorPages added

src/ApplicationCore/Entities/BuyerAggregate/Buyer.cs

@@ -1,8 +1,7 @@
 using ApplicationCore.Interfaces;
+using Ardalis.GuardClauses;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
-using System;
 using System.Collections.Generic;
-using System.Text;
 
 namespace ApplicationCore.Entities.BuyerAggregate
 {
@@ -14,13 +13,15 @@ namespace ApplicationCore.Entities.BuyerAggregate
 
         public IEnumerable<PaymentMethod> PaymentMethods => _paymentMethods.AsReadOnly();
 
-        protected Buyer()
+        private Buyer()
         {
+            // required by EF
         }
 
         public Buyer(string identity) : this()
         {
-            IdentityGuid = !string.IsNullOrWhiteSpace(identity) ? identity : throw new ArgumentNullException(nameof(identity));
+            Guard.Against.NullOrEmpty(identity, nameof(identity));
+            IdentityGuid = identity;
         }
     }
 }

src/ApplicationCore/Entities/OrderAggregate/Address.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 
 namespace ApplicationCore.Entities.OrderAggregate
 {

src/ApplicationCore/Entities/OrderAggregate/CatalogItemOrdered.cs

@@ -1,21 +1,29 @@
-namespace ApplicationCore.Entities.OrderAggregate
+using Ardalis.GuardClauses;
+
+namespace ApplicationCore.Entities.OrderAggregate
 {
     /// <summary>
-    /// Represents the item that was ordered. If catalog item details change, details of
+    /// Represents a snapshot of the item that was ordered. If catalog item details change, details of
     /// the item that was part of a completed order should not change.
     /// </summary>
     public class CatalogItemOrdered // ValueObject
     {
         public CatalogItemOrdered(int catalogItemId, string productName, string pictureUri)
         {
+            Guard.Against.OutOfRange(catalogItemId, nameof(catalogItemId), 1, int.MaxValue);
+            Guard.Against.NullOrEmpty(productName, nameof(productName));
+            Guard.Against.NullOrEmpty(pictureUri, nameof(pictureUri));
+
             CatalogItemId = catalogItemId;
             ProductName = productName;
             PictureUri = pictureUri;
         }
+
         private CatalogItemOrdered()
         {
             // required by EF
         }
+
         public int CatalogItemId { get; private set; }
         public string ProductName { get; private set; }
         public string PictureUri { get; private set; }

src/ApplicationCore/Entities/OrderAggregate/Order.cs

@@ -1,4 +1,5 @@
 using ApplicationCore.Interfaces;
+using Ardalis.GuardClauses;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
 using System;
 using System.Collections.Generic;
@@ -9,13 +10,18 @@ namespace ApplicationCore.Entities.OrderAggregate
     {
         private Order()
         {
+            // required by EF
         }
 
         public Order(string buyerId, Address shipToAddress, List<OrderItem> items)
         {
+            Guard.Against.NullOrEmpty(buyerId, nameof(buyerId));
+            Guard.Against.Null(shipToAddress, nameof(shipToAddress));
+            Guard.Against.Null(items, nameof(items));
+
+            BuyerId = buyerId;
             ShipToAddress = shipToAddress;
             _orderItems = items;
-            BuyerId = buyerId;
         }
         public string BuyerId { get; private set; }
 
@@ -43,6 +49,5 @@ namespace ApplicationCore.Entities.OrderAggregate
             }
             return total;
         }
-
     }
 }

src/ApplicationCore/Entities/OrderAggregate/OrderItem.cs

@@ -9,9 +9,11 @@ namespace ApplicationCore.Entities.OrderAggregate
         public decimal UnitPrice { get; private set; }
         public int Units { get; private set; }
 
-        protected OrderItem()
+        private OrderItem()
         {
+            // required by EF
         }
+
         public OrderItem(CatalogItemOrdered itemOrdered, decimal unitPrice, int units)
         {
             ItemOrdered = itemOrdered;