public void TestUpdateFilm()
        {
            var updateToThis = new Models.Film {
                Description = "this movie change your life", Length = 109, ReleaseYear = 1999, Title = "Jumanji"
            };

            var data = new List <DatabaseClient.TableEntity.Film>
            {
                new Film {
                    description = "Wystraczy Cię na śmierć", film_id = 2, length = 97, release_year = 2001, title = "Jumanji"
                },
            }.AsQueryable();

            var mockSet = new Mock <DbSet <Film> >();

            mockSet.As <IQueryable <Film> >().Setup(m => m.Provider).Returns(data.Provider);
            mockSet.As <IQueryable <Film> >().Setup(m => m.Expression).Returns(data.Expression);
            mockSet.As <IQueryable <Film> >().Setup(m => m.ElementType).Returns(data.ElementType);
            mockSet.As <IQueryable <Film> >().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator());

            var mockContext = new Mock <DVDRentalContext>();

            mockContext.Setup(context => context.Films).Returns(mockSet.Object);
            repository = new FilmContext(mockContext.Object);

            var updated = data.FirstOrDefault();

            repository.UpdateFilm(updateToThis);



            Assert.AreEqual(updateToThis.Description, updated.description);
            Assert.AreEqual(updateToThis.ReleaseYear, updated.release_year);
            Assert.AreEqual(updateToThis.Length, updated.length);

            mockContext.Verify(m => m.SaveChanges(), Times.Once());
        }