docs(#1802): add direct unit testing requirement for helper functions

[fullsend-ai-coder]

What:

Add documentation requiring direct unit tests for new public helper functions in policy/lib/.

Changes:

• AGENTS.md: New "Testing New Helper Functions" section after the review checklist, specifying that new helpers must have direct tests covering each logical branch, edge cases, and the function contract independently of callers.
• .claude/rules/policy-rules.md: New bullet reinforcing that indirect coverage alone is not sufficient for helper functions.

Why:

During PR #1781, human reviewer st3penta identified that the lacks_effective_anchor helper had 4 logical branches tested only indirectly through anchoring_errors. While CI's 100% coverage gate was met, the indirect tests did not guarantee all edge-case combinations were exercised. This convention exists in practice (most helpers in policy/lib/ already have direct test suites) but was not documented, so automated reviewers had no basis to flag the gap.

Tickets:

#1802

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Closes #1802

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[fullsend-ai-review]

🤖 Finished Review · ✅ Success · Started 10:35 AM UTC · Completed 10:46 AM UTC

Commit: 87c4a29 · View workflow run →

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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unit-tests	100.00% <ø> (ø)

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[fullsend-ai-review]

Review

Findings

Medium

• [protected-path] .claude/rules/policy-rules.md, AGENTS.md — Both modified files are under protected paths (.claude/ and AGENTS.md). The PR links to issue Add direct unit testing requirement for new helper functions to AGENTS.md #1802 and provides clear rationale for documenting the direct unit testing requirement. Human approval is always required for protected-path changes, regardless of context.

Low

• [documentation formatting consistency] AGENTS.md:107 — The new "Testing New Helper Functions" section uses bare dash bullets (e.g., - Each logical branch of the function) whereas the checklist-style sections in AGENTS.md (Key Conventions, Common Change Patterns, Review Checklist for New Policy Rules) use the - **Bold label:** description pattern. The Rego Evaluation Model section also uses bare dashes, so this is not universally inconsistent, but the new section is closer in nature to the checklist sections.
  Remediation: Consider reformatting bullets to match the checklist pattern, e.g., - **Branch coverage:** Exercise each logical branch of the function.

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Labels: PR is a documentation-only change modifying AGENTS.md and .claude/rules/policy-rules.md

[fullsend-ai-review]

See the review comment for full details.

[fullsend-ai-review]

[low] documentation formatting consistency

The new 'Testing New Helper Functions' section uses bare dash bullets whereas the checklist-style sections in AGENTS.md (Key Conventions, Common Change Patterns, Review Checklist for New Policy Rules) use the '- Bold label: description' pattern. The Rego Evaluation Model section also uses bare dashes, so this is not universally inconsistent, but the new section is closer in nature to the checklist sections.

Suggested fix: Consider reformatting bullets to match the checklist pattern, e.g., '- Branch coverage: Exercise each logical branch of the function'.