Refactoring and Adding Tests (#28)

* Introducing repository and refactoring services.
Changing entities to use int keys everywhere.

* Refactoring application services to live in web project and only reference repositories, not EF contexts.

* Cleaning up implementations

* Moving logic out of CatalogController
Moving entity knowledge out of viewmodels.

* Implementing specification includes better for catalogservice

* Cleaning up and adding specification unit tests

tests/UnitTests/ApplicationCore/Specifications/BasketWithItemsSpecification.cs

@@ -0,0 +1,48 @@
+using ApplicationCore.Specifications;
+using Microsoft.eShopWeb.ApplicationCore.Entities;
+using System.Collections.Generic;
+using System.Linq;
+using Xunit;
+
+namespace UnitTests
+{
+    public class BasketWithItems
+    {
+        private int _testBasketId = 123;
+
+        [Fact]
+        public void MatchesBasketWithGivenId()
+        {
+            var spec = new BasketWithItemsSpecification(_testBasketId);
+
+            var result = GetTestBasketCollection()
+                .AsQueryable()
+                .FirstOrDefault(spec.Criteria);
+
+            Assert.NotNull(result);
+            Assert.Equal(_testBasketId, result.Id);
+
+        }
+
+        [Fact]
+        public void MatchesNoBasketsIfIdNotPresent()
+        {
+            int badId = -1;
+            var spec = new BasketWithItemsSpecification(badId);
+
+            Assert.False(GetTestBasketCollection()
+                .AsQueryable()
+                .Any(spec.Criteria));
+        }
+
+        public List<Basket> GetTestBasketCollection()
+        {
+            return new List<Basket>()
+            {
+                new Basket() { Id = 1 },
+                new Basket() { Id = 2 },
+                new Basket() { Id = _testBasketId }
+            };
+        }
+    }
+}