public async Task AddSamplePlaylistShouldAddSamplePlaylist()
        {
            var sample = new SamplePlaylist();

            _projectBLMock.Setup(x => x.AddSamplePlaylistAsync(It.IsAny <SamplePlaylist>())).Returns(Task.FromResult <SamplePlaylist>(sample));
            var sampleController = new SamplePlaylistController(_projectBLMock.Object);
            var result           = await sampleController.AddSamplePlaylistAsync(new SamplePlaylist());

            Assert.IsAssignableFrom <CreatedAtActionResult>(result);
            _projectBLMock.Verify(x => x.AddSamplePlaylistAsync((It.IsAny <SamplePlaylist>())));
        }
        public async Task AddSamplePlaylistAsync_ShouldReturnStatusCode400_WhenSamplePlaylistIsInvalid()
        {
            //arrange
            SamplePlaylist samplePlaylist = null;

            _projectBLMock.Setup(i => i.AddSamplePlaylistAsync(samplePlaylist)).Throws(new Exception());
            SamplePlaylistController samplePlaylistController = new SamplePlaylistController(_projectBLMock.Object);

            //act
            var result = await samplePlaylistController.AddSamplePlaylistAsync(samplePlaylist);

            //assert
            Assert.IsType <StatusCodeResult>(result);
            Assert.Equal(400, ((StatusCodeResult)result).StatusCode);
        }