feat: make sure max_video_quality setting is working

tests/test_download_quality_format.py

@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+from src.app.core.download.downloader import Downloader
+
+
+def test_build_format_defaults_to_best_mp4():
+    fmt = Downloader.build_format(None)
+    assert "height<=" not in fmt
+    assert "best[ext=mp4]" in fmt
+
+
+def test_build_format_applies_height_cap():
+    fmt = Downloader.build_format("720p")
+    assert "height<=720" in fmt
+