from playlist import Playlist

def test_addAndSelectOneSong():
    songAddedByUser = "/path/to/song"
    songSetByCallback = None

    def testCallback(song):
        nonlocal songSetByCallback
        songSetByCallback = song

    uut = Playlist(testCallback)
    uut.addSong(songAddedByUser)
    uut.setCurrentSong(0)

    assert songAddedByUser == songSetByCallback
    assert uut.getCurrentSong() == 0

def test_addTwoSongsAndSelectBoth():
    songAddedByUser = ["/path/to/song", "/path/to/second/song"]
    songSetByCallback = None

    def testCallback(song):
        nonlocal songSetByCallback
        songSetByCallback = song

    uut = Playlist(testCallback)
    uut.addSong(songAddedByUser[0])
    uut.addSong(songAddedByUser[1])

    uut.setCurrentSong(0)
    assert songAddedByUser[0] == songSetByCallback
    assert uut.getCurrentSong() == 0

    uut.setCurrentSong(1)
    assert songAddedByUser[1] == songSetByCallback
    assert uut.getCurrentSong() == 1

def test_firstAddedSongIsSelected():
    songAddedByUser = "/path/to/song"
    songSetByCallback = None

    def testCallback(song):
        nonlocal songSetByCallback
        songSetByCallback = song

    uut = Playlist(testCallback)
    uut.addSong(songAddedByUser)

    assert songAddedByUser == songSetByCallback
    assert uut.getCurrentSong() == 0

def test_invalidSongSelection():
    songAddedByUser = "/path/to/song"
    songSetByCallback = None

    def testCallback(song):
        nonlocal songSetByCallback
        songSetByCallback = song

    uut = Playlist(testCallback)
    assert songSetByCallback == None

    uut.setCurrentSong(10)
    assert songSetByCallback == None
    assert uut.getCurrentSong() == None

    uut.addSong(songAddedByUser)
    uut.setCurrentSong(10)
    assert songSetByCallback == songAddedByUser
    assert uut.getCurrentSong() == 0