Adding guards and more tests (#68)

* Adding single entity by spec method to repository

* Adding guards and more unit tests

src/ApplicationCore/ApplicationCore.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Ardalis.GuardClauses" Version="1.1.1" />
     <PackageReference Include="System.Security.Claims" Version="4.3.0" />
   </ItemGroup>
 

src/ApplicationCore/Exceptions/BasketNotFoundException.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace ApplicationCore.Exceptions
+{
+    public class BasketNotFoundException : Exception
+    {
+        public BasketNotFoundException(int basketId) : base($"No basket found with id {basketId}")
+        {
+        }
+
+        protected BasketNotFoundException(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) : base(info, context)
+        {
+        }
+
+        public BasketNotFoundException(string message) : base(message)
+        {
+        }
+
+        public BasketNotFoundException(string message, Exception innerException) : base(message, innerException)
+        {
+        }
+    }
+}

src/ApplicationCore/Exceptions/GuardExtensions.cs

@@ -0,0 +1,14 @@
+using ApplicationCore.Exceptions;
+using Microsoft.eShopWeb.ApplicationCore.Entities;
+
+namespace Ardalis.GuardClauses
+{
+    public static class FooGuard
+    {
+        public static void NullBasket(this IGuardClause guardClause, int basketId, Basket basket)
+        {
+            if (basket == null)
+                throw new BasketNotFoundException(basketId);
+        }
+    }
+}

src/ApplicationCore/Interfaces/IRepository.cs

@@ -1,12 +1,12 @@
 using Microsoft.eShopWeb.ApplicationCore.Entities;
 using System.Collections.Generic;
-using System.Threading.Tasks;
 
 namespace ApplicationCore.Interfaces
 {
     public interface IRepository<T> where T : BaseEntity
     {
         T GetById(int id);
+        T GetSingleBySpec(ISpecification<T> spec);
         IEnumerable<T> ListAll();
         IEnumerable<T> List(ISpecification<T> spec);
         T Add(T entity);

src/ApplicationCore/Services/BasketService.cs

@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using ApplicationCore.Specifications;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
 using System.Linq;
+using Ardalis.GuardClauses;
 
 namespace ApplicationCore.Services
 {
@@ -43,6 +44,7 @@ namespace ApplicationCore.Services
 
         public async Task<int> GetBasketItemCountAsync(string userName)
         {
+            Guard.Against.NullOrEmpty(userName, nameof(userName));
             var basketSpec = new BasketWithItemsSpecification(userName);
             var basket = (await _basketRepository.ListAsync(basketSpec)).FirstOrDefault();
             if (basket == null)
@@ -57,7 +59,9 @@ namespace ApplicationCore.Services
 
         public async Task SetQuantities(int basketId, Dictionary<string, int> quantities)
         {
+            Guard.Against.Null(quantities, nameof(quantities));
             var basket = await _basketRepository.GetByIdAsync(basketId);
+            Guard.Against.NullBasket(basketId, basket);
             foreach (var item in basket.Items)
             {
                 if (quantities.TryGetValue(item.Id.ToString(), out var quantity))
@@ -71,6 +75,8 @@ namespace ApplicationCore.Services
 
         public async Task TransferBasketAsync(string anonymousId, string userName)
         {
+            Guard.Against.NullOrEmpty(anonymousId, nameof(anonymousId));
+            Guard.Against.NullOrEmpty(userName, nameof(userName));
             var basketSpec = new BasketWithItemsSpecification(anonymousId);
             var basket = (await _basketRepository.ListAsync(basketSpec)).FirstOrDefault();
             if (basket == null) return;

src/ApplicationCore/Services/OrderService.cs

@@ -3,6 +3,7 @@ using ApplicationCore.Entities.OrderAggregate;
 using System.Threading.Tasks;
 using Microsoft.eShopWeb.ApplicationCore.Entities;
 using System.Collections.Generic;
+using Ardalis.GuardClauses;
 
 namespace ApplicationCore.Services
 {
@@ -24,6 +25,7 @@ namespace ApplicationCore.Services
         public async Task CreateOrderAsync(int basketId, Address shippingAddress)
         {
             var basket = await _basketRepository.GetByIdAsync(basketId);
+            Guard.Against.NullBasket(basketId, basket);
             var items = new List<OrderItem>();
             foreach (var item in basket.Items)
             {