The test spawns its fixture subprocess with `stderr: "ignore"` (line 48), silently discarding all subprocess error output. When CodeRabbit suggested removing the flaky `expect(stderr).not.toContain("error:")` assertion, the correct fix was to keep `stderr: "pipe"` and drop only that assertion — not to discard stderr entirely. If the fixture ever fails in CI (e.g., chmod did not take effect, shebang problem, binary not found), the only failure information will be a mismatched stdout or exit-code