The shared test session kept whatever a failing handler flushed and never
committed, so a later read in the test saw a write production loses when
get_db closes the session — and a handler whose failure path must commit
(E16: the tracker's issue link) looked right without the commit.
Round 2 of the deep review, on round 1's own fixes:
- `ORDER BY position … FOR UPDATE` sorts before it locks, so the reorder that waited got the
fresh rows in its STALE order and dealt the pins it left out (a tab with Plex off) back to their
old slots. It locks in id order — one global order, so two reorders cannot deadlock — and sorts
the fresh rows itself. The race test now sends that partial list and fails unless tab B really
blocked.
- The request check saw only writes the handler flushed: a `db.delete` left staged, or a flush
followed by a released savepoint, passed. Staged changes count at the end of the request, and
only the ROOT transaction's end clears it (a savepoint test drives the dependency directly).
- The `ok` test exempted every call as a serializer, hiding four domain REPORTS (YouTube sync,
revert, push; Plex sync) without `ok`. They are spread into `{"ok": True, …}`; the exemption is a
named list of real serializers.
Helpers flush and handlers commit — but every test request shared the test's session, so a
follow-up GET or an assertion read the flushed write and the suite stayed green over a handler
whose commit was missing (production's get_db closes the session: the write is rolled back behind
a 200). The db fixture now hands out `db.info["request"]`: the same session, recording each request
that ends normally with a flushed, uncommitted write, and failing the test on it at teardown. All
28 get_db overrides use it (a convention test keeps it so); the full suite passes under it, and
dropping the commit from add_item turns a playlist test red.
22 test files set `app.dependency_overrides[...]` by hand and tore down with a blanket `.clear()`
in a `finally`, which wipes every override rather than the test's own and stops fixtures composing.
They now take the `override_dep` fixture (helpers get it passed in), whose teardown restores each
key's prior value; no clear() carried meaning between two phases of a test. A convention test fails
any test file that writes `dependency_overrides` directly.
peter