Standing in for an abandoned compositor means binding a Unix socket, and the sandboxes this guard exists for are the ones that deny it: the fixture raised PermissionError and took the whole file down with set -e, adding a failure in the environment the guard was written to keep clean. Run the cases that need no socket first and skip the rest when one cannot be bound. Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>