tests: isolate the VIDEO database too (never open the real video_library.db)

conftest already redirected the MUSIC DB to a tmp path after test writes once
corrupted a user's music library (WSL/NTFS + WAL). The VIDEO side had the SAME
hazard but no guard: VideoDatabase()/get_video_db() with no path resolve from
VIDEO_DATABASE_PATH, defaulting to the real database/video_library.db, and its
enrichment threads WRITE — a default-path open during tests corrupted the real
video library (one table's btree pages; recovered via row-by-row salvage).

Fix: set VIDEO_DATABASE_PATH to the same throwaway tmp dir at conftest import,
before anything loads. Adds guard tests proving VideoDatabase()/get_video_db()
never resolve to database/video_library.db (mirrors the music guards).

tests/conftest.py

@@ -16,6 +16,13 @@ endpoints and event handlers without importing the full web_server.py
 # that call get_database() with no path → the real DB. Running those writers
 # against the live DB over a WSL-mounted Windows drive corrupted a user's
 # library. This guarantees it can't recur — tests get their own disposable DB.
+#
+# The VIDEO side has the SAME hazard: VideoDatabase()/get_video_db() with no
+# path resolves from os.environ['VIDEO_DATABASE_PATH'] (see
+# database/video_database.py) → the real database/video_library.db, and its
+# enrichment threads WRITE. A blueprint/handler test that opened the default
+# VideoDatabase corrupted the real video library once — same WSL/NTFS + WAL
+# trap. So redirect VIDEO_DATABASE_PATH to /tmp here too, before any import.
 import os as _os
 import tempfile as _tempfile
 import atexit as _atexit
@@ -24,6 +31,7 @@ import shutil as _shutil
 if not _os.environ.get('SOULSYNC_TEST_DB_READY'):
     _TEST_DB_DIR = _tempfile.mkdtemp(prefix='soulsync-testdb-')
     _os.environ['DATABASE_PATH'] = _os.path.join(_TEST_DB_DIR, 'test_music_library.db')
+    _os.environ['VIDEO_DATABASE_PATH'] = _os.path.join(_TEST_DB_DIR, 'test_video_library.db')
     _os.environ['SOULSYNC_TEST_DB_READY'] = '1'
     _atexit.register(lambda: _shutil.rmtree(_TEST_DB_DIR, ignore_errors=True))
 

tests/test_db_isolation_guard.py

@@ -1,8 +1,9 @@
-"""Guard: the test suite must NEVER resolve the real database/music_library.db.
+"""Guard: the test suite must NEVER resolve the real music OR video library DB.
 
-Tests exercise modules that call get_database() with no path. If that resolves
+Tests exercise modules that call get_database()/get_video_db() with no path. If
-to the live DB, test writes can corrupt a real library (this happened, over a
+that resolves to a live DB, test writes can corrupt a real library (this
-WSL-mounted Windows drive). conftest.py sets DATABASE_PATH to a temp file before
+happened to BOTH the music and the video library, over a WSL-mounted Windows
+drive). conftest.py sets DATABASE_PATH + VIDEO_DATABASE_PATH to temp files before
 anything imports; these tests prove it sticks for every default-path access.
 """
 
@@ -30,3 +31,23 @@ def test_get_database_path_never_real():
     from database.music_database import get_database
     resolved = str(Path(get_database().database_path).resolve())
     assert 'soulsync-testdb-' in resolved, resolved
+
+
+# ── Video side — same hazard, same guarantee ──────────────────────────────
+
+def test_video_database_path_env_is_isolated():
+    p = os.environ.get('VIDEO_DATABASE_PATH', '')
+    assert 'soulsync-testdb-' in p, f"VIDEO_DATABASE_PATH not isolated: {p!r}"
+
+
+def test_videodatabase_default_path_never_real():
+    from database.video_database import VideoDatabase
+    resolved = str(Path(VideoDatabase().database_path).resolve())
+    assert 'soulsync-testdb-' in resolved, resolved
+    assert not resolved.replace('\\', '/').endswith('database/video_library.db'), resolved
+
+
+def test_get_video_db_path_never_real():
+    from api.video import get_video_db
+    resolved = str(Path(get_video_db().database_path).resolve())
+    assert 'soulsync-testdb-' in resolved, resolved