[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!

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