Unit Testing Sitecore ContentSearch (LINQ to Sitecore) using Moq

ProductRepository.cs

using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using Sitecore.Abstractions;
using Sitecore.ContentSearch;
using Sitecore.Data.Items;

namespace BasicCompany.Feature.Products.Services
{
	public class ProductRepository : IProductRepository
	{
		protected readonly BaseFactory Factory;
		protected readonly BaseItemManager ItemManager;

		public ProductRepository(BaseFactory factory, BaseItemManager itemManager)
		{
			Debug.Assert(factory != null);
			Debug.Assert(itemManager != null);
			Factory = factory;
			ItemManager = itemManager;
		}

		public IEnumerable<Item> GetProducts(Item parent)
		{
			using (var context = GetSearchContext(parent))
			{
				var results = context.GetQueryable<ProductSearchQuery>()
					.Where(product => product.Paths.Contains(parent.ID) && product.Templates.Contains(Templates.Product.Id))
					.Select(x => new {
						Uri = x.UniqueId,
						Database = Factory.GetDatabase(x.UniqueId.DatabaseName)
					}).ToList();
				return results.Select(x => ItemManager.GetItem(x.Uri.ItemID, x.Uri.Language, x.Uri.Version, x.Database));
			}
		}

		protected virtual IProviderSearchContext GetSearchContext(Item item)
		{
			return ContentSearchManager.GetIndex((SitecoreIndexableItem)item).CreateSearchContext();
		}
	}
}

ProductRepositoryTests.cs

using System.Linq;
using BasicCompany.Feature.Products.Services;
using Moq;
using Moq.Protected;
using Sitecore.Abstractions;
using Sitecore.ContentSearch;
using Sitecore.Data;
using Sitecore.Data.Items;
using Sitecore.Globalization;
using Xunit;
using Version = Sitecore.Data.Version;

namespace BasicCompany.Feature.Products.Tests
{
	public class ProductRepositoryTests
	{
		[Fact]
		public void FiltersOnPathAndTemplate()
		{
			// Mock the database
			var db = Mock.Of<Database>();

			// Mock the parent item
			var parentId = ID.NewID;
			var parentDef = new ItemDefinition(parentId, "parent", Templates.Product.Id, ID.Null);
			var parentData = new ItemData(parentDef, Language.Parse("en"), Version.Parse(1), new FieldList());
			var parent = new Mock<Item>(parentId, parentData, db);

			// Mock the Sitecore services
			var factoryMock = new Mock<BaseFactory>();
			factoryMock.Setup(x => x.GetDatabase(It.IsAny<string>())).Returns(db);
			var factory = factoryMock.Object;
			var itemManager = Mock.Of<BaseItemManager>();

			// Mock search context, so we are testing LINQ to Objects instead of LINQ to Sitecore
			var itemUri = new ItemUri("sitecore://master/{11111111-1111-1111-1111-111111111111}?lang=en&ver=1");
			var mockSearchContext = new Mock<IProviderSearchContext>();
			mockSearchContext.Setup(x => x.GetQueryable<ProductSearchQuery>())
				.Returns(new[]
				{
					// Matches Path and Template
					new ProductSearchQuery
					{
						UniqueId = itemUri,
						Templates = new[] {Templates.Product.Id },
						Paths = new[] { parentId }
					},
					// Matches Path and Template
					new ProductSearchQuery
					{
						UniqueId = itemUri,
						Templates = new[] { ID.NewID, Templates.Product.Id, ID.NewID },
						Paths = new[] { ID.NewID, parentId, ID.NewID }
					},
					// Matches Template Only
					new ProductSearchQuery
					{
						UniqueId = itemUri,
						Templates = new[] { Templates.Product.Id },
						Paths = new[] { ID.NewID }
					},
					// Matches Path Only
					new ProductSearchQuery
					{
						UniqueId = itemUri,
						Templates = new[] { ID.NewID },
						Paths = new[] { parentId }
					}
				}.AsQueryable());

			// Use Moq.Protected to ensure our test object uses the mock search context
			var mockRepo = new Mock<ProductRepository>(factory, itemManager);
			mockRepo.Protected()
				.Setup<IProviderSearchContext>("GetSearchContext", ItExpr.IsAny<Item>())
				.Returns(mockSearchContext.Object);

			// Act
			var result = mockRepo.Object.GetProducts(parent.Object).ToList();

			// If the tested class is filtering appropriately, we should get predictible results
			Assert.Equal(2, result.Count);
		}
	}
}

ProductSearchQuery.cs

using System.Collections.Generic;
using Sitecore.ContentSearch;
using Sitecore.Data;

namespace BasicCompany.Feature.Products.Services
{
	public class ProductSearchQuery
	{
		[IndexField("_uniqueid")]
		public virtual ItemUri UniqueId { get; set; }
		[IndexField("_path")]
		public virtual IEnumerable<ID> Paths { get; set; }
		[IndexField("_templates")]
		public virtual IEnumerable<ID> Templates { get; set; }
	}
}