public void GetAllReturnsAllElements() { // Arrange var films = new List <Film> { new Film { Rating = 2 }, new Film { Rating = 3 } }.AsQueryable(); var mockSet = new Mock <DbSet <Film> >(); mockSet.As <IQueryable <Film> >().Setup(m => m.Provider).Returns(films.Provider); mockSet.As <IQueryable <Film> >().Setup(m => m.Expression).Returns(films.Expression); mockSet.As <IQueryable <Film> >().Setup(m => m.ElementType).Returns(films.ElementType); mockSet.As <IQueryable <Film> >().Setup(m => m.GetEnumerator()).Returns(films.GetEnumerator()); var mockContext = new Mock <CinemaDbContext>(); mockContext.Setup(c => c.Films).Returns(mockSet.Object); var filmBusiness = new FilmBusiness(mockContext.Object); // Act var allFilms = filmBusiness.GetAll().ToList(); // Assert Assert.AreEqual(2, allFilms.Count, "Doesn't return all elements of the film."); }