run_gateway() calls refresh_systemd_unit_if_needed() on every invocation
so restart settings stay current after exit-code-75 respawns. The
user-scope unit path resolves under Path.home() (NOT sandboxed by
conftest, only HERMES_HOME is), and generate_systemd_unit() bakes the
current HERMES_HOME into the unit's Environment= line.
Result: any test that exercises run_gateway() end-to-end on a real
Linux dev box silently rewrites the developer's installed
~/.config/systemd/user/hermes-gateway.service with a polluted
HERMES_HOME pointing at /tmp/pytest-of-<user>/.../hermes_test. On the
next reboot, systemd loads that unit, the gateway starts looking at an
empty tmp dir, and Telegram/Discord/etc. all show as 'No messaging
platforms enabled' even though the user's real config is fine. Three
tests in tests/hermes_cli/test_gateway.py hit this path:
test_run_gateway_exits_cleanly_on_keyboard_interrupt,
test_run_gateway_exits_nonzero_when_start_gateway_reports_failure, and
test_run_gateway_root_guard_has_escape_hatch.
Two-layer fix:
1. _install_fake_gateway_run helper (covers all four run_gateway() call
sites in test_gateway.py and any future ones) now also stubs
supports_systemd_services and refresh_systemd_unit_if_needed.
2. refresh_systemd_unit_if_needed() itself sniffs the generated unit
body for /pytest-of- and /hermes_test markers and refuses to write
when present. Defense in depth so a future test that bypasses the
helper still can't corrupt the dev's gateway. Tests that legitimately
exercise the refresh flow (test_run_gateway_refreshes_outdated_unit_on_boot)
patch generate_systemd_unit to return synthetic content that doesn't
carry those markers, so they keep working.
Adds test_refresh_refuses_to_bake_pytest_tmpdir_into_real_user_unit as a
regression test for the source-side guard.
2ffef15675