public async Task GetTopTracks()
        {
            var testTracks = new List <Track>
            {
                new Track {
                    Id = 1, Score = 1
                },
                new Track {
                    Id = 2, Score = 2
                },
                new Track {
                    Id = 3, Score = 3
                }
            };

            _context.AddRange(testTracks);
            _context.SaveChanges();

            var spec   = new TopTracksSpecification(2);
            var tracks = await _trackRepository.ListAsync(spec);

            Assert.AreEqual(3, tracks.First().Id);
            Assert.AreEqual(2, tracks.Count());
        }