Sitecore Content Search Unit Test

ContentSearchTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using Moq;
using NUnit.Framework;
using Sitecore.ContentSearch;
using Sitecore.ContentSearch.Linq;
using Sitecore.ContentSearch.SearchTypes;

namespace Website
{
    [TestFixture]
    public class ContentSearchTest
    {
        [Test]
        public void GetProductsTest()
        {
            // arrange
            var repository = new TestableSearchRepository();

            // act
            var products = repository.GetProducts(null);

            // assert
            Assert.AreEqual(2, products.Count());
        }
    }

    public class ProductSearchResultItem : SearchResultItem
    {
        [IndexField("free")]
        public virtual bool Free { get; set; }
    }


    public class SearchRepository
    {
        public virtual IEnumerable<ProductSearchResultItem> GetProducts(SitecoreIndexableItem item)
        {
            using (var context = this.GetSearchContext(item))
            {
                var query = context.GetQueryable<ProductSearchResultItem>();

                var allProducts = query.GetResults();

                var products = query.Filter(searchResultItem => searchResultItem.Free);

                return products.ToList();
            }
        }

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

    public class TestableSearchRepository : SearchRepository
    {
        protected override IProviderSearchContext GetSearchContext(SitecoreIndexableItem item)
        {
            // create the magic product index
            var index = new List<ProductSearchResultItem>();

            index.Add(new ProductSearchResultItem { Free = true });
            index.Add(new ProductSearchResultItem { Free = false });
            index.Add(new ProductSearchResultItem { Free = true });

            // create the mock context
            var context = new Mock<IProviderSearchContext>();
            context.Setup(c => c.GetQueryable<ProductSearchResultItem>()).Returns(index.AsQueryable());
            return context.Object;
        }
    }

    public static class ExtensionMocks
    {
        public static SearchResults<TSource> GetResults<TSource>(this IQueryable<TSource> source)
        {
            return new SearchResults<TSource>(source.Select(s => new SearchHit<TSource>(0, s)), 0);
        }

        public static IQueryable<TSource> Filter<TSource>(this IQueryable<TSource> source, Expression<Func<TSource, bool>> predicate)
        {
            return source.Where(predicate);
        }
    }
}

This is really useful, but in case anyone ends up in the same situation as me, this doesn't work for queries involving facets.