db: Reload the New Tracks playlist at midnight

The New Tracks playlist shows tracks that have been added within the
past week. We should automatically reload it a few seconds after
midnight to keep it up to date as tracks drop off the list.

Implements: #58 ("Reload New Tracks playlist at midnight")
Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/db/playlists.py

@@ -1,7 +1,9 @@
 # Copyright 2022 (c) Anna Schumaker
 """A custom Gio.ListModel for working with playlists."""
+import datetime
 import sqlite3
 from gi.repository import GObject
+from .. import alarm
 from . import playlist
 from . import tracks
 
@@ -57,6 +59,11 @@ class Table(playlist.Table):
     def __init__(self, sql: GObject.TYPE_PYOBJECT, **kwargs):
         """Initialize the Playlists Table."""
         super().__init__(sql=sql, system_tracks=False, **kwargs)
+        alarm.set_alarm(datetime.time(hour=0, minute=0, second=5),
+                        self.__at_midnight)
+
+    def __at_midnight(self) -> None:
+        self.new_tracks.reload_tracks()
 
     def __move_user_trackid(self, playlist: Playlist, trackid: int,
                             *, offset: int) -> bool:

tests/db/test_playlists.py

@@ -1,5 +1,6 @@
 # Copyright 2022 (c) Anna Schumaker
 """Tests our playlist Gio.ListModel."""
+import datetime
 import pathlib
 import unittest.mock
 import emmental.db
@@ -326,6 +327,18 @@ class TestSystemPlaylists(tests.util.TestCase):
                                             pathlib.Path("/a/b/1.ogg"),
                                             self.medium, self.year)
 
+    def test_midnight_alarm(self):
+        """Test playlist maintenance run every night at midnight."""
+        with unittest.mock.patch.object(self.table.new_tracks,
+                                        "reload_tracks") as mock_reload:
+            self.table._Table__at_midnight()
+            mock_reload.assert_called()
+
+        with unittest.mock.patch("emmental.alarm.set_alarm") as mock_set:
+            table2 = emmental.db.playlists.Table(self.sql)
+            mock_set.assert_called_with(datetime.time(second=5),
+                                        table2._Table__at_midnight)
+
     def test_collection(self):
         """Test the Collection playlist."""
         self.assertIsInstance(self.table.collection,