test: the rewritten write handlers commit, and three more owner filters hold

Each handler that now calls a service and commits is driven through HTTP once.
A second account's watch state, Watch later list and private download profile
are never read or changed. The autotag job's orphan prune is seen committed.

backend/tests/test_owner_scoping.py

@@ -10,7 +10,10 @@ from datetime import datetime, timedelta, timezone
 from sqlalchemy import func, select
 
 from app import debugsession, notifications, quota
+from app.catalog.models import Channel, Video
+from app.downloads.models import DownloadJob, DownloadProfile
 from app.models import DebugScreenshot, DebugSession, Notification, QuotaEvent
+from app.reader.models import Playlist, PlaylistItem, VideoState
 from app.routes import tokens as tokens_routes
 from app.routes.auth import RESET_TTL, _issue_token
 
@@ -133,3 +136,113 @@ def test_screenshot_storage_counts_only_mine(db, make_user):
         )
     db.commit()
     assert debugsession.stored_screenshot_bytes(db, me.id) == 10
+
+
+# --- the units' owner filters, through their routes --------------------------------------------
+# The same rule one layer up: a second account acting on the SAME video, list or profile id must
+# reach only its own row. Each test holds the first account's row unchanged afterwards.
+
+
+def _videos(db, *ids):
+    db.add(Channel(id="UCo", title="O"))
+    db.flush()
+    for vid in ids:
+        db.add(
+            Video(
+                id=vid,
+                channel_id="UCo",
+                published_at=datetime.now(timezone.utc),
+                duration_seconds=3600,
+            )
+        )
+    db.commit()
+
+
+def _video_state(db, user, vid="v1"):
+    db.expire_all()
+    row = db.execute(
+        select(VideoState).where(VideoState.user_id == user.id, VideoState.video_id == vid)
+    ).scalar_one_or_none()
+    return None if row is None else (row.status, row.position_seconds)
+
+
+def test_unmarking_a_video_leaves_another_users_state(db, make_user, as_user):
+    me, other = make_user(), make_user()
+    _videos(db, "v1")
+    db.add(VideoState(user_id=other.id, video_id="v1", status="watched"))
+    db.commit()
+    r = as_user(me).post("/api/videos/v1/state", json={"status": "new"})
+    assert r.status_code == 200, r.text
+    assert _video_state(db, other) == ("watched", 0)
+
+
+def test_clearing_a_video_leaves_another_users_state(db, make_user, as_user):
+    me, other = make_user(), make_user()
+    _videos(db, "v1")
+    db.add(VideoState(user_id=other.id, video_id="v1", status="hidden", position_seconds=90))
+    db.commit()
+    assert as_user(me).delete("/api/videos/v1/state").status_code == 200
+    assert _video_state(db, other) == ("hidden", 90)
+
+
+def test_a_resume_point_is_set_and_cleared_on_my_own_row_only(db, make_user, as_user):
+    me, other = make_user(), make_user()
+    _videos(db, "v1")
+    db.add(VideoState(user_id=other.id, video_id="v1", status="hidden", position_seconds=90))
+    db.commit()
+    client = as_user(me)
+    body = {"position_seconds": 600, "duration_seconds": 3600}
+    assert client.post("/api/videos/v1/progress", json=body).status_code == 200
+    assert (_video_state(db, me), _video_state(db, other)) == (("new", 600), ("hidden", 90))
+    body = {"position_seconds": 0, "duration_seconds": 3600}
+    assert client.post("/api/videos/v1/progress", json=body).status_code == 200
+    assert (_video_state(db, me), _video_state(db, other)) == (None, ("hidden", 90))
+
+
+def _watch_later_ids(db, user):
+    db.expire_all()
+    return sorted(
+        db.execute(
+            select(PlaylistItem.video_id)
+            .join(Playlist, Playlist.id == PlaylistItem.playlist_id)
+            .where(Playlist.user_id == user.id, Playlist.kind == "watch_later")
+        ).scalars()
+    )
+
+
+def test_watch_later_adds_and_removes_use_my_own_list(db, make_user, as_user):
+    me, other = make_user(), make_user()
+    _videos(db, "v1", "v2")
+    theirs = as_user(other).post("/api/playlists/watch-later", json={"video_id": "v1"}).json()
+    client = as_user(me)
+    mine = client.post("/api/playlists/watch-later", json={"video_id": "v2"}).json()
+    assert mine["playlist_id"] != theirs["playlist_id"]
+    # Their saved video is not on my list, so removing it from mine leaves theirs alone.
+    assert client.delete("/api/playlists/watch-later/v1").status_code == 200
+    assert (_watch_later_ids(db, me), _watch_later_ids(db, other)) == (["v2"], ["v1"])
+
+
+def test_another_users_private_profile_is_refused_like_a_missing_one(db, make_user, as_user):
+    me, other = make_user(), make_user()
+    theirs = DownloadProfile(user_id=other.id, name="Theirs", spec={"format": "best"})
+    builtin = DownloadProfile(user_id=None, name="Best", spec={"format": "best"}, is_builtin=True)
+    db.add_all([theirs, builtin])
+    db.commit()
+    client = as_user(me)
+
+    def enqueue(profile_id):
+        return client.post(
+            "/api/downloads", json={"source": "dQw4w9WgXcQ", "profile_id": profile_id}
+        )
+
+    missing = enqueue(theirs.id + builtin.id + 1)
+    refused = enqueue(theirs.id)
+    assert (refused.status_code, refused.json()) == (404, missing.json())
+    assert refused.json()["detail"] == {"code": "not_found", "reason": "profile"}
+    db.expire_all()
+    assert db.execute(select(DownloadJob)).first() is None
+    # A built-in is everyone's to use.
+    r = enqueue(builtin.id)
+    assert r.status_code == 200, r.text
+    db.expire_all()
+    assert db.execute(select(DownloadJob.profile_id)).scalars().all() == [builtin.id]