public void GetPreviousSong()
        {
            SongToPlay song1 = new SongToPlay();
            SongToPlay song2 = new SongToPlay { IsPlaying = true };
            SongToPlay song3 = new SongToPlay();
            PlayList playList = new PlayList();
            playList.SongsToPlay.Add(song1);
            playList.SongsToPlay.Add(song2);
            playList.SongsToPlay.Add(song3);

            Assert.AreEqual(song1, playList.GetPreviousSong());
        }
        public void GetPreviousSong()
        {
            SongToPlay song1 = CreateViewModel.SongToPlay(null);
            SongToPlay song2 = CreateViewModel.SongToPlay(null, true);
            SongToPlay song3 = CreateViewModel.SongToPlay(null);
            PlayList playList = new PlayList();
            playList.SongsToPlay.Add(song1);
            playList.SongsToPlay.Add(song2);
            playList.SongsToPlay.Add(song3);

            Assert.AreEqual(song1, playList.GetPreviousSong());
        }