Wie verspotte ich die AsNoTracking-Methode?
Im folgenden Beispiel wurde DbContext in die Serviceklasse eingefügt. Es funktioniert einwandfrei, wenn ich die AsNoTracking-Erweiterungsmethode aus der GetOrderedProducts-Methode entferne, der AsNoTracking-Test jedoch fehlschlägt, da er null zurückgibt. Ich habe auch versucht, AsNoTracking zu verspotten, um den richtigen Wert zurückzugeben, aber es hat nicht funktioniert.

public interface IUnitOfWork
{
    IDbSet<TEntity> Set<TEntity>() where TEntity : class;
    int SaveAllChanges();
}

public class Entites : DbContext, IUnitOfWork
{
    public virtual DbSet<Product> Products { get; set; }  // This is virtual because Moq needs to override the behaviour

    public new virtual IDbSet<TEntity> Set<TEntity>() where TEntity : class   // This is virtual because Moq needs to override the behaviour 
    {
        return base.Set<TEntity>();
    }

    public int SaveAllChanges()
    {
        return base.SaveChanges();
    }
}

    public class ProductService
{
    private readonly IDbSet<Product> _products;
    private readonly IUnitOfWork _uow;

    public ProductService(IUnitOfWork uow)
    {
        _uow = uow;
        _products = _uow.Set<Product>();
    }
    public IEnumerable<Product> GetOrderedProducts()
    {
        return _products.AsNoTracking().OrderBy(x => x.Name).ToList();
    }
}

    [TestFixture]
public class ProductServiceTest
{
    private readonly ProductService _productService;

    public ProductServiceTest()
    {
        IQueryable<Product> data = GetRoadNetworks().AsQueryable();
        var mockSet = new Mock<DbSet<Product>>();
        mockSet.As<IQueryable<Product>>().Setup(m => m.Provider).Returns(data.Provider);
        mockSet.As<IQueryable<Product>>().Setup(m => m.Expression).Returns(data.Expression);
        mockSet.As<IQueryable<Product>>().Setup(m => m.ElementType).Returns(data.ElementType);
        mockSet.As<IQueryable<Product>>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator());
        var context = new Mock<Entites>();
        context.Setup(c => c.Products).Returns(mockSet.Object);
        context.Setup(m => m.Set<Product>()).Returns(mockSet.Object);
        context.Setup(c => c.Products.AsNoTracking()).Returns(mockSet.Object);
        _productService = new ProductService(context.Object);
    }

    private IEnumerable<Product> GetRoadNetworks()
    {
        return new List<Product>
        {
            new Product
            {
                Id = 1,
                Name = "A"
            },
            new Product
            {
                Id = 2,
                Name = "B"
            },
            new Product
            {
                Id = 1,
                Name = "C"
            }
        };
    }

    [Test]
    public void GetOrderedProductTest()
    {
        IEnumerable<Product> products = _productService.GetOrderedProducts();
        List<string> names = products.Select(x => x.Name).ToList();
        var expected = new List<string> {"A", "B", "C"};
        CollectionAssert.AreEqual(names, expected);
    }
}

Das Problem ist, dass AsNoTracking im Komponententest null zurückgibt.