public async Task CallsAudioPlayerPlay() { var audioPlayerCallback = Substitute.For<IMediaPlayerCallback>(); using (Library library = new LibraryBuilder().WithPlaylist().WithAudioPlayer(audioPlayerCallback).Build()) { Guid token = library.LocalAccessControl.RegisterLocalAccessToken(); Song song = Helpers.SetupSongMock(); library.AddSongToPlaylist(song); await library.PlaySongAsync(0, token); await library.ContinueSongAsync(token); } audioPlayerCallback.Received(2).PlayAsync(); }