[MohamedRF]

Description
Running .github/scripts/run-random-tests.sh --max-jobs 1 hangs before starting PHPUnit. When no child processes remain, cleanup_finished_pids() assigns ("${active[@]:-}"), creating an array with one empty element. The scheduler counts that element as an active job and waits indefinitely.

Keep the process list empty when there are no active PIDs. Add RunRandomTestsTest to tests/system/AutoReview/, following the existing script-test convention. Each case builds an isolated temporary project with two stub components and calls the runner through exec(), checking its exit code, success output, and two executions per component. The data provider covers job limits of one and two. A five-second timeout with a one-second kill grace prevents a regression from hanging PHPUnit; the temporary project is removed in teardown. The existing AutoReview workflow discovers the test without workflow changes.

Refs #9968. This fixes the runner rather than completing the component migration tracked by that issue.

Validation

• vendor/bin/phpunit tests/system/AutoReview/RunRandomTestsTest.php --no-coverage: 2 tests, 12 assertions pass.
• With the original runner restored temporarily, the one-job test fails on timeout; with the fix restored, both cases pass.
• File-scoped PHP CS Fixer, Rector dry run, and PHPStan checks pass.
• git diff --check passes.
• Tested locally with PHP 8.5.12, PHPUnit 11.5.57, Bash 3.2, and GNU coreutils on macOS. Full platform validation is left to CI.

Checklist:

• Securely signed commits
• Regression testing
• Conforms to style guide
• PHPDoc and user guide changes: not applicable; no framework API or application behavior changes.

[carson-codeigniter4]

Hi there, @MohamedRF! 👋

Thank you for sending this PR!

We expect the following in all Pull Requests (PRs).

• PRs must be sent to the appropriate branch
• All git commits must be GPG-signed
• Must follow our style guide
• Be commented in the PHP source file
• Be documented in the user guide
• Be unit tested
• Pass all checks in GitHub Actions

Important

We expect all code changes or bug-fixes to be accompanied by one or more tests added to our test suite to prove the code works.

If pull requests do not comply with the above, they will likely be closed. Since we are a team of volunteers, we don't have any more time to work
on the framework than you do. Please make it as painless for your contributions to be included as possible.

See https://github.com/codeigniter4/CodeIgniter4/blob/develop/contributing/pull_request.md

[paulbalandan]

this can use is_windows()

[paulbalandan]

why do you need to set GITHUB_ACTIONS env explicitly here?

[paulbalandan]

timeout is unavailable on my macos. can this unconditional timeout be tested for availability first, then for gtimeout, then skip if none available?