test(guard): stabilize spawn-race fixtures

[eggrollofchaos]

Summary

• model mocked guard processes as live in claim-focused contention tests
• keep fresh dead-PID protection covered by a deterministic unit test

Verification

• uv run --frozen --with pytest pytest tests/test_guard_race_2026_05_18.py::TestR1_DaemonProcessRace::test_two_processes_one_winner tests/test_spawn_lock.py::TestThreeProcessContention::test_three_process_contention tests/test_spawn_lock.py::TestV4TenProcessContention::test_ten_process_contention_30x tests/test_spawn_lock.py::TestFreshClaimProtection::test_fresh_dead_pid_is_not_reclaimed -q

[eggrollofchaos]

Findings

High

1. tests/test_spawn_lock.py:455-463 — The new "fresh dead PID" regression test is not deterministic under the supported COZEMPIC_PIDFILE_FRESH_SECONDS configuration. The implementation accepts any finite value in (0, 300], but the test advances its mocked clock by a fixed 1.0 second. With the valid setting COZEMPIC_PIDFILE_FRESH_SECONDS=0.1, the file is correctly classified as stale, the claim is reclaimed, and this new test fails. Reproducer: COZEMPIC_PIDFILE_FRESH_SECONDS=0.1 env -u COZEMPIC_NO_AUTO_INIT uv run --frozen --with pytest pytest tests/test_spawn_lock.py::TestFreshClaimProtection::test_fresh_dead_pid_is_not_reclaimed -q. Fix by patching _FRESH_PIDFILE_SECONDS to a known value for this unit or deriving a mocked age strictly inside the active imported window.

Low

2. tests/test_spawn_lock.py:457-463 — The new exception assertion leaves two calls in the expected-exception region and triggers the sole Sonar annotation on this PR. Construct the claim outside the assertion, then put only claim.__enter__() (or an equivalent single helper call) inside assertRaises; assertRaises already fails if no exception is raised, so the explicit self.fail(...) is unnecessary.

Verification

• Packet command: 4 passed in 20.81s.
• Valid short-window probe above: 1 failed, reproducing the High finding.
• Valid long-window probe (COZEMPIC_PIDFILE_FRESH_SECONDS=300): 1 passed.
• git diff --check fd41e95b85f283286eaca9419c19825abb6d053b..605aa1341c06859f186d198dd89c061de04f26d5: passed.
• PR context checked at head 605aa1341c06859f186d198dd89c061de04f26d5: 1 top-level bot comment, 0 inline comments, 0 review threads (0 active), 0 prior reviews. The Sonar quality gate passed with the one Low annotation described above.

Counts: 0 Critical, 1 High, 0 Medium, 1 Low, 0 Nit.

Verdict: Critical/High findings remain.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[eggrollofchaos]

Self-review verdict: LGTM — approve.

The v2 continuation closes both prior findings:

• The fresh-dead-PID test now derives its mocked age from the active _FRESH_PIDFILE_SECONDS value, so it remains strictly inside every supported positive window. Independent probes passed at 0.1, 1e-9, and 300 seconds.
• The expected-exception block now contains only claim.__enter__(), removing the multi-call assertion ambiguity and the prior static-analysis concern.

I also re-read both changed test files in full and traced the fixtures through start_guard_daemon, DaemonSpawnClaim, _is_process_alive, and the shared freshness gate. Treating the synthetic positive PIDs as alive correctly models the peer hand-off and makes the two-, three-, and ten-process contention fixtures independent of host PID state without weakening the production assertion.

Findings: none.

Verification:

• Exact-head targeted suite: 4 passed in 16.84s.
• Fresh-window probes: 0.1, 1e-9, and 300 each passed.
• Exact head: b6fea7251c191f2c422a794d639f79cbec12a3ce over base fd41e95b85f283286eaca9419c19825abb6d053b.
• PR context checked immediately before verdict: SonarCloud passed with 0 new issues; 1 top-level bot comment; 0 inline comments; 0 review threads; no unresolved current-head feedback; merge state CLEAN.

Counts: 0 Critical, 0 High, 0 Medium, 0 Low, 0 Nit.

Merge blocker: none from this review. This is a neutral confirmation only; no approval or merge action was performed.