# pytest-xdist test fixes

With two workers and a restart limit of three, the fourth worker crash
requests shutdown while another test can still be running. That test may
also crash. The original queued-work test requires exactly four failures,
even though five failures can occur without exceeding the replacement limit.

## Scope and behavior

`concurrent-worker-crashes.patch` changes the assertions in
`TestNodeFailure.test_max_worker_restart_tests_queued` in
`testing/acceptance_test.py`. It requires exactly three replacements, four or
five failed tests, the failed-tests exit status, the limit message, and no
internal error. It retains the two-worker workload and ten queued tests.

`worker-startup-timeout.patch` changes the remote-test helper's event timeout
from 10 to 60 seconds so loaded builders have time to start workers. The
helper returns immediately when an event arrives and still has a bounded wait.

The existing nixpkgs pytest-9 compatibility patches remain in place.
Production scheduling and worker-restart behavior are unchanged.

## Reproduction and focused checks

Use a disposable pytest-xdist 3.8.0 checkout with its test dependencies and
the nixpkgs pytest-9 compatibility patches where required. From this directory:

```sh
patch --fuzz=0 -d /path/to/pytest-xdist -p1 < concurrent-worker-crashes.patch
patch --fuzz=0 -d /path/to/pytest-xdist -p1 < worker-startup-timeout.patch
cd /path/to/pytest-xdist
python -m pytest testing/acceptance_test.py \
  -k test_max_worker_restart_tests_queued -q
python -m pytest testing/test_remote.py -q
```

Twenty unmodified runs passed during the review. To force the failing
schedule, modify the generated crashing test in a disposable checkout to
accept `worker_id`: make `gw3` wait for a marker created by `gw4`, and make
`gw4` pause 0.1 seconds after creating the marker. Then both have in-flight
tests when shutdown starts. Bound the marker wait so a reproduction failure
cannot hang the suite. The original assertion fails on five reported
failures; the patched test passes.

## Worker startup and outer concurrency

[`default.nix`](default.nix) runs the outer suite with one worker to limit
nested process pools. This is a Nix test-runner setting; the source timeout
change lives in [`worker-startup-timeout.patch`](worker-startup-timeout.patch).

A separate reproduction inserts an 11-second `pytest_sessionstart` delay
into the child created by `test_basic_collect_and_runtests` in
`testing/test_remote.py`. The original 10-second channel wait fails; the
60-second wait passes. This bounds waits for test worker events, including
startup, rather than changing a product deadline.

## Upstream status

These are standalone test patches for pytest-xdist 3.8.0. No upstream submission
was made during this work. Recheck the allowed in-flight failures, replacement
count, and remote-test wait when updating the scheduler or worker behavior.

## Local NixOS integration and build results

[`../default.nix`](../default.nix) loads `default.nix` through
`pythonPackagesExtensions`. From the repository root:

```sh
nix build --no-link -L .#nixosConfigurations.jeeves.pkgs.python314Packages.pytest-xdist
```

After consolidating the settings in this directory, the full x86-64-v3 package
build passed 185 tests, with 6 existing skips and 10 expected failures. Nix
evaluation confirmed the same outer-worker limit and preserved existing
patches, with the timeout now applied as a source patch.

The earlier forced concurrent-crash and delayed-startup reproductions passed
after their fixes; the focused crash test also passed after formatting its
assertion.