Adding more spec tests (#29)

tests/UnitTests/ApplicationCore/Specifications/CatalogFilterSpecificationFilter.cs

@@ -0,0 +1,42 @@
+using ApplicationCore.Specifications;
+using Microsoft.eShopWeb.ApplicationCore.Entities;
+using System.Collections.Generic;
+using System.Linq;
+using Xunit;
+
+namespace UnitTests
+{
+    public class CatalogFilterSpecificationFilter
+    {
+        [Theory]
+        [InlineData(null, null, 5)]
+        [InlineData(1, null, 3)]
+        [InlineData(2, null, 2)]
+        [InlineData(null, 1, 2)]
+        [InlineData(null, 3, 1)]
+        [InlineData(1, 3, 1)]
+        [InlineData(2, 3, 0)]
+        public void MatchesExpectedNumberOfItems(int? brandId, int? typeId, int expectedCount)
+        {
+            var spec = new CatalogFilterSpecification(brandId, typeId);
+
+            var result = GetTestItemCollection()
+                .AsQueryable()
+                .Where(spec.Criteria);
+
+            Assert.Equal(expectedCount, result.Count());
+        }
+
+        public List<CatalogItem> GetTestItemCollection()
+        {
+            return new List<CatalogItem>()
+            {
+                new CatalogItem() { Id = 1, CatalogBrandId = 1, CatalogTypeId= 1 },
+                new CatalogItem() { Id = 2, CatalogBrandId = 1, CatalogTypeId= 2 },
+                new CatalogItem() { Id = 3, CatalogBrandId = 1, CatalogTypeId= 3 },
+                new CatalogItem() { Id = 4, CatalogBrandId = 2, CatalogTypeId= 1 },
+                new CatalogItem() { Id = 5, CatalogBrandId = 2, CatalogTypeId= 2 },
+            };
+        }
+    }
+}