public void GetNextSongPathTest() { PlayListModel playListModel = new PlayListModel { SongPath = path }; PlayListViewModel.ListBoxItems.Add(playListModel); Assert.AreEqual(path, playListViewModel.GetNextSongPath(-1)); Assert.AreEqual(path, playListViewModel.GetNextSongPath(5)); PlayListViewModel.ListBoxItems.Clear(); Assert.IsNull(playListViewModel.GetNextSongPath(0)); }