Add the data layer with the build-db, fetch-lyrics, and fetch-artists subcommands

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tools/tests/test_models.py

@@ -0,0 +1,95 @@
+# Tools for A Feminist Audit of Pop Music.
+# Copyright 2026 imacat.  All rights reserved.
+# Authors:
+#   imacat@mail.imacat.idv.tw (imacat), 2026/7/31
+# AI assistance: Claude Code (Anthropic)
+"""Unit tests for the data models."""
+import unittest
+
+import sqlalchemy as sa
+from sqlalchemy.orm import Session
+
+from pop_fem_audit_tools import config
+from pop_fem_audit_tools.database import Base, DataSource
+from pop_fem_audit_tools.models import (
+    Artist,
+    ChartEntry,
+    Song,
+    SongArtist,
+)
+
+
+class TestModels(unittest.TestCase):
+    """Test cases for the data models."""
+
+    def setUp(self) -> None:
+        """Create the schema on an in-memory SQLite database."""
+        config.set_settings(config.Settings(
+            SQLALCHEMY_DATABASE_URL="sqlite://",
+            ANTHROPIC_API_KEY="test-key"))
+        self.__ds: DataSource = DataSource()
+        Base.metadata.create_all(self.__ds.engine)
+        self.__session: Session = self.__ds.get_db()
+        self.addCleanup(self.__session.close)
+
+    def __add_song(self) -> None:
+        """Add a song with chart entries, artists, and lyrics.
+
+        :return: None.
+        """
+        song: Song = Song(title="One Dance",
+                          artist_credit="Drake featuring Wizkid")
+        song.chart_entries = [ChartEntry(year=2016, rank=4)]
+        song.song_artists = [
+            SongArtist(artist=Artist(name="Drake"),
+                       role="primary", position=0),
+            SongArtist(artist=Artist(name="Wizkid"),
+                       role="featured", position=1)]
+        song.lyrics = "Baby, I like your style"
+        self.__session.add(song)
+        self.__session.commit()
+
+    def test_song_graph(self) -> None:
+        """Test reading a song graph back through relationships."""
+        self.__add_song()
+        self.__session.expunge_all()
+        song: Song | None = self.__session.scalar(
+            sa.select(Song).where(Song.title == "One Dance"))
+        assert song is not None
+        self.assertEqual(song.artist_credit,
+                         "Drake featuring Wizkid")
+        self.assertEqual([(x.year, x.rank)
+                          for x in song.chart_entries],
+                         [(2016, 4)])
+        self.assertEqual([(x.artist.name, x.role, x.position)
+                          for x in song.song_artists],
+                         [("Drake", "primary", 0),
+                          ("Wizkid", "featured", 1)])
+        self.assertEqual(song.lyrics,
+                         "Baby, I like your style")
+        artist: Artist | None = self.__session.scalar(
+            sa.select(Artist).where(Artist.name == "Wizkid"))
+        assert artist is not None
+        self.assertEqual([x.song.title for x in artist.song_artists],
+                         ["One Dance"])
+
+    def test_duplicated_song_rejected(self) -> None:
+        """Test that a duplicated title and artist credit fails."""
+        self.__add_song()
+        self.__session.add(
+            Song(title="One Dance",
+                 artist_credit="Drake featuring Wizkid"))
+        with self.assertRaises(sa.exc.IntegrityError):
+            self.__session.commit()
+
+    def test_invalid_role_rejected(self) -> None:
+        """Test that an invalid song-artist role fails."""
+        self.__add_song()
+        song: Song | None = self.__session.scalar(
+            sa.select(Song).where(Song.title == "One Dance"))
+        assert song is not None
+        self.__session.add(
+            SongArtist(song=song, artist=Artist(name="Kyla"),
+                       role="cover", position=2))
+        with self.assertRaises(sa.exc.IntegrityError):
+            self.__session.commit()