db: Give Artists a function for listing their Albums

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

db/artist.py

@@ -9,6 +9,7 @@
 # +------------------+
 # | name -> artistid |
 # +------------------+
+from . import album
 from . import execute
 from . import objects
 
@@ -17,6 +18,11 @@ class Artist(objects.Tag):
         return execute(f"SELECT {column} FROM artists "
                         "WHERE artistid=?", [ self.rowid ])
 
+    def albums(self):
+        cursor = execute(f"SELECT albumid FROM albums "
+                          "WHERE artistid=?", [ self.rowid ])
+        return [ album.Album(row["albumid"]) for row in cursor.fetchall() ]
+
 
 class ArtistTable(objects.Table):
     def __init__(self):

db/test_artist.py

@@ -49,3 +49,9 @@ class TestArtistTable(unittest.TestCase):
         artist = db.artist.Table.insert("Test Artist", "Test Sort")
         self.assertEqual(db.artist.Table.lookup("Test Artist"), artist)
         self.assertIsNone(db.artist.Table.lookup("none"))
+
+    def test_artist_albums(self):
+        artist = db.artist.Table.find("Test Artist", "Test Sort")
+        a = db.album.Table.find(artist, "A")
+        b = db.album.Table.find(artist, "B")
+        self.assertEqual(artist.albums(), [ a, b ])