add option for following nightly yt-dlp releases (closes #999)

app/tests/test_config.py

@@ -107,6 +107,22 @@ class ConfigTests(unittest.TestCase):
             c = Config()
         self.assertTrue(c.ALLOW_YTDL_OPTIONS_OVERRIDES)
 
+    def test_ytdl_nightly_update_time_empty_default(self):
+        with patch.dict(os.environ, _base_env(YTDL_NIGHTLY_UPDATE_TIME=""), clear=False):
+            c = Config()
+        self.assertEqual(c.YTDL_NIGHTLY_UPDATE_TIME, "")
+
+    def test_ytdl_nightly_update_time_valid(self):
+        with patch.dict(os.environ, _base_env(YTDL_NIGHTLY_UPDATE_TIME="04:00"), clear=False):
+            c = Config()
+        self.assertEqual(c.YTDL_NIGHTLY_UPDATE_TIME, "04:00")
+
+    def test_ytdl_nightly_update_time_invalid_exits(self):
+        for bad in ("25:00", "4am", "12:60"):
+            with patch.dict(os.environ, _base_env(YTDL_NIGHTLY_UPDATE_TIME=bad), clear=False):
+                with self.assertRaises(SystemExit):
+                    Config()
+
     def test_runtime_override_roundtrip(self):
         with patch.dict(os.environ, _base_env(), clear=False):
             c = Config()

app/tests/test_nightly_update.py

@@ -0,0 +1,29 @@
+"""Tests for nightly yt-dlp update scheduling helpers."""
+
+from __future__ import annotations
+
+import unittest
+from datetime import datetime
+
+from main import seconds_until_next_daily_time
+
+
+class NightlyUpdateTests(unittest.TestCase):
+    def test_seconds_until_later_today(self):
+        now = datetime(2026, 6, 4, 10, 0, 0)
+        delay = seconds_until_next_daily_time("15:30", now)
+        self.assertEqual(delay, 5 * 3600 + 30 * 60)
+
+    def test_seconds_until_wraps_to_next_day(self):
+        now = datetime(2026, 6, 4, 18, 0, 0)
+        delay = seconds_until_next_daily_time("04:00", now)
+        self.assertEqual(delay, 10 * 3600)
+
+    def test_seconds_until_same_minute_is_next_day(self):
+        now = datetime(2026, 6, 4, 4, 0, 30)
+        delay = seconds_until_next_daily_time("04:00", now)
+        self.assertAlmostEqual(delay, 24 * 3600 - 30, delta=1)
+
+
+if __name__ == "__main__":
+    unittest.main()