public void getartist_should_thrown_exception_with_null_id()
        {
            var repository = new ArtistRepository(_catalogDataContextFactory.ContextInstance);

            var sut = new GetArtistHandler(repository);

            sut.Handle(null, CancellationToken.None).ShouldThrow <ArgumentNullException>();
        }
        public async Task getartist_should_return_right_artist(string id)
        {
            var repository = new ArtistRepository(_catalogDataContextFactory.ContextInstance);

            var sut = new GetArtistHandler(repository);

            var result = await sut.Handle(new GetArtistCommand { Id = new Guid(id) }, CancellationToken.None);

            result.ShouldNotBeNull();
        }