Get row and track from playlist.tracks with tests

app/models.py

@@ -9,7 +9,7 @@ from datetime import datetime
 from mutagen.flac import FLAC
 from mutagen.mp3 import MP3
 from sqlalchemy.ext.associationproxy import association_proxy
-from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.ext.declarative import declarative_base, DeclarativeMeta
 from sqlalchemy import (
     Boolean,
     Column,
@@ -21,8 +21,9 @@ from sqlalchemy import (
     func
 )
 from sqlalchemy.exc import IntegrityError
-from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
 from sqlalchemy.orm import backref, relationship, sessionmaker, scoped_session
+from sqlalchemy.orm.collections import attribute_mapped_collection
+from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
 
 from app.config import Config
 from app.helpers import (
@@ -237,6 +238,7 @@ class Playlists(Base):
                          back_populates="playlist")
 
     tracks = association_proxy('playlist_tracks', 'tracks')
+    row = association_proxy('playlist_tracks', 'row')
 
     def __init__(self, session, name):
         self.name = name
@@ -341,7 +343,13 @@ class PlaylistTracks(Base):
     track_id = Column(Integer, ForeignKey('tracks.id'), primary_key=True)
     row = Column(Integer, nullable=False)
     tracks = relationship("Tracks")
-    playlist = relationship(Playlists, backref=backref("playlist_tracks"))
+    playlist = relationship(
+        Playlists,
+        backref=backref(
+            "playlist_tracks",
+            collection_class=attribute_mapped_collection("row")
+        )
+    )
 
     def __init__(self, session, playlist_id, track_id, row):
         DEBUG(f"PlaylistTracks.__init__({playlist_id=}, {track_id=}, {row=})")

test_models.py

@@ -172,13 +172,36 @@ def test_playlist_add_track(session):
     track_path = "/a/b/c"
     track = Tracks(session, track_path)
 
-    playlist.add_track(session, track)
+    row = 17
+
+    playlist.add_track(session, track, row)
 
     assert len(playlist.tracks) == 1
-    playlist_track = playlist.tracks[0]
+    playlist_track = playlist.tracks[row]
     assert playlist_track.path == track_path
 
 
+def test_playlist_tracks(session):
+    # We need a playlist
+    playlist = Playlists(session, "my playlist")
+
+    # We need two tracks
+    track1_path = "/a/b/c"
+    track1_row = 17
+    track1 = Tracks(session, track1_path)
+
+    track2_path = "/x/y/z"
+    track2_row = 29
+    track2 = Tracks(session, track2_path)
+
+    playlist.add_track(session, track1, track1_row)
+    playlist.add_track(session, track2, track2_row)
+
+    tracks = playlist.tracks
+    assert tracks[track1_row] == track1
+    assert tracks[track2_row] == track2
+
+
 def test_playlist_open_and_close(session):
 
     # We need a playlist