check_subprocess_stdin.py already had a full-repo-scan pytest wrapper
(test_subprocess_stdin_guard.py), so a plain pytest run catches a
regression there without anyone remembering to run the script by
hand. check-windows-footguns.py had no equivalent (only a narrow
single-rule test existed), which is why the bare os.killpg/
signal.SIGKILL regression in the npx-agent-browser hardening commit
shipped past local testing and was only caught by CI running the
script directly. New test_windows_footguns_full_repo_scan.py mirrors
the stdin guard's exact pattern to close that asymmetry.
Also adds direct coverage for _kill_process_tree's getattr fallback
when os.killpg is missing, and asserts warm_agent_browser_npx_cache's
Popen call passes stdin=subprocess.DEVNULL as a literal argument.
94f095e8b7