public async Task Index_ExpectedNotNull_ReturnsViewResult()
        {
            var controller = new PlaylistControllerBuilder()
                             .Build();

            var result = await controller.Index(CancellationToken.None) as ViewResult;

            result.Should().NotBeNull();
        }
        public void Index_ExpectedException_ReturnsOutOfRangeException()
        {
            var controller = new PlaylistControllerBuilder()
                             .Build();

            Func <Task> result = async()
                                 => await controller.Index(CancellationToken.None, 0);

            result.Should().Throw <ArgumentOutOfRangeException>();
        }