fix: decrement plays after playback

tests/test_music_player.py

@@ -27,6 +27,17 @@ class MusicPlayerQueueTest(unittest.IsolatedAsyncioTestCase):
 
         self.assertIs(voice_client.playing, track)
         self.assertEqual(player.state(GUILD).index, 0)
+        self.assertEqual(track.plays_left, 5)
+
+    async def test_finish_current_decrements_plays_without_going_below_zero(self):
+        player, _ = build_player(default_plays=1)
+        track = FakeTrack("a")
+        await player.enqueue(GUILD, track)
+
+        player.finish_current(GUILD)
+        player.finish_current(GUILD)
+
+        self.assertEqual(track.plays_left, 0)
 
     async def test_last_play_remains_pointed_to_until_playback_finishes(self):
         player, _ = build_player(default_plays=1)
@@ -51,7 +62,7 @@ class MusicPlayerQueueTest(unittest.IsolatedAsyncioTestCase):
         await player.play_next(GUILD, advance=True)
         self.assertEqual([track.id for track in state.queue], ["a", "b", "c"])
         self.assertEqual(state.index, 0)
-        self.assertEqual(state.current.plays_left, 0)
+        self.assertEqual(state.current.plays_left, 1)
 
         await player.play_next(GUILD, advance=True)
 
@@ -162,7 +173,7 @@ class MusicPlayerQueueTest(unittest.IsolatedAsyncioTestCase):
         await player.enqueue(1, first)
         await player.enqueue(2, second)
 
-        self.assertEqual(first.plays_left, 1)
+        self.assertEqual(first.plays_left, 2)
         self.assertEqual(second.plays_left, 7)
 
     async def test_broken_tracks_stop_instead_of_looping_forever(self):