public void GetArtist_WithValidId_ShouldReturnArtist()
        {
            // arrange
            var id = Guid.NewGuid();

            service.Setup(s => s.Get(id))
            .Returns(new Artist {
                Id = id
            });

            // act
            var response = controller.GetArtist(id);

            Artist actual;

            response.TryGetContentValue(out actual);

            // assert
            Assert.That(response.StatusCode == HttpStatusCode.OK);

            Assert.That(actual, Is.Not.Null);
            Assert.That(actual.Id == id);
        }