test: assert expired key directly now that time-machine controls clock

[27Bslash6]

Summary

• Remove workaround in test_ttl_enforced that avoided reading expired keys directly due to a file handle bug in FileBackend
• With time-machine controlling the clock (added in test: eliminate flaky time.sleep() tests with time-machine #94), backend.get("temporary") correctly returns None after advancing past TTL
• Subsumes the fix from stale PR fix: CodeRabbit auto-fixes for PR #94 #95 (CodeRabbit auto-fix targeting a deleted branch)

Test plan

• test_ttl_enforced passes locally (verified 5/5 runs)
• CI passes

Summary by CodeRabbit

Release Notes

No user-facing changes in this release. This update includes internal test improvements to verify existing functionality.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 22c3df82-67f8-4aa8-9a73-879e29ef84d1

📥 Commits

Reviewing files that changed from the base of the PR and between 4fb674b and 5c56397.

📒 Files selected for processing (1)

• tests/critical/test_file_backend_critical.py

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📝 Walkthrough

Walkthrough

The test test_ttl_enforced was simplified to directly assert that an expired key returns None after the clock advances past its TTL, replacing a prior workaround that avoided reading the expired key and instead validated behavior through a separate key write/read cycle.

Changes

TTL Expiry Test Simplification

Layer / File(s)	Summary
Test Improvement tests/critical/test_file_backend_critical.py	test_ttl_enforced now directly asserts backend.get("temporary") is None after advancing past the TTL, removing the workaround that skipped reading the expired key.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Possibly related PRs

• test: eliminate flaky time.sleep() tests with time-machine #94: Introduced time_machine-based time shifts and the workaround assertion pattern that this PR removes in favor of direct TTL expiry verification.

Poem

🐰 A rabbit hops through test code neat,
Where workarounds once dodged the heat.
Now TTL truth shines crystal clear—
Direct assertions, no tricks here!
Expired keys return None, sincere. ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description includes Summary and Test plan sections, but omits required template sections like Motivation, Type of Change, and various checklists.	Add missing required sections: Motivation (explain why the workaround removal is needed), Type of Change (select appropriate category), and complete relevant checklists per the template.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: removing a workaround and asserting expired keys directly now that time-machine controls the clock.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/ttl-test-workaround

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