maziggy 7490c93081 ci: balance the backend test shards by measured time, not test count ...

Backend Tests (shard 1/4) timed out after 10 minutes on e8b901f54
    ("Updated BACKERS"), a docs-only commit. The step was not hung: it
    reached 98%, every test passing, and was killed about 12 seconds short
    of finishing.

    pytest-split balances by duration only when it has a durations file,
    and there was none. Without one it splits by test COUNT -- 2926 / 2926
    / 2926 / 2925, exactly 25% each, which is what the comment here claimed
    was good enough. Count is not time. Measured over the full suite
    (11703 tests, 1045.6s):

        shard 1   2926 tests   658.2s
        shard 2   2926 tests   173.1s
        shard 3   2926 tests   113.3s
        shard 4   2925 tests   101.1s

    Shard 1 was carrying 63% of the suite's runtime -- a 6.5x spread -- and
    had been walking toward the cap for weeks: 475s, 404s, 445s, then 587s
    on 08-30, thirteen seconds under it, and 613s here. CI printed the
    reason in its own log on every run: "[pytest-split] No test durations
    found."

    Commit tests/.test_durations and pass --durations-path explicitly:

        shard 1   1273 tests   261.6s
        shard 2   1070 tests   261.5s
        shard 3   1522 tests   262.0s
        shard 4   7838 tests   260.6s

    A 1.01x spread. The lopsided test counts are the point: shard 4 takes
    thousands of fast unit tests, shard 1 keeps the slow integration ones.
    The four groups still partition the suite exactly -- union is 11703
    with nothing dropped or duplicated, and all four pass.

    --durations-path has to be explicit because pytest-split defaults it to
    $CWD/.test_durations, and the two matrices run from different
    directories: the native job from backend/, the Docker job from the
    image root. Left implicit, the Docker one finds nothing and silently
    falls back to the count split. Node IDs match across both because
    backend/tests/pytest.ini pins rootdir to backend/tests either way, so a
    single file serves them both; verified the file clears .dockerignore
    and lands at /app/backend/tests/.test_durations at full size.

    timeout-minutes 10 -> 15 for headroom, since the file goes stale as
    tests are added. Staleness degrades slowly rather than breaking --
    unknown tests are treated as average.

2026-09-20 13:22:17 +02:00

..

app

Bumped version

2026-09-20 13:19:02 +02:00

tests

ci: balance the backend test shards by measured time, not test count

2026-08-31 17:13:09 +02:00

__init__.py

…