test(repo): prefer test.each over for/forEach loops in tests

[rafa-thayto]

Summary

• Adds a new convention to .claude/rules/testing.md: tests should use test.each (or it.each / describe.each) instead of for/forEach loops inside a single test, so each case becomes its own reported test with pinpointed failure attribution.
• Converts every existing hand-rolled parameterization loop in the test suite to test.each. Test count grows from 1450 → 1528 (each test.each row becomes a separately reported case); zero new failures.
• Documents the two carve-outs: loops are fine when the iteration is the behavior under test, or when the data is collected at runtime and can't be expressed as a static module-load table.
• Documents the Bun test.each readonly-array gotcha: spread as const/readonly arrays to a mutable copy (test.each([...MODES])) so Bun's literal-inferring overload preserves the union in the callback type.

Files refactored

File	Change
cli-program.test.ts	two outer for loops → cross-product test.each(AGENT_DIR_CASES) + test.each([...EXTRA_REL_PATHS])
bootstrap.test.ts	nested registry × package-manager loops → test.each(REGISTRY_PM_PAIRS)
skill/install.test.ts	two per-file version assertion loops → test.each(VERSION_FILE_CASES)
lib/listage.test.ts	two for (active = 0; <20; ...) property tests → cross-product test.each(SCROLL_CASES)
lib/users.test.ts	assertion-loop over invalid JSON inputs → test.each
integration/onboard.test.ts	nested for (mode) { test.each(frameworks) } → flattened test.each(ONBOARD_CASES) with explicit FrameworkCase interface
integration/switch-apps.test.ts	outer for (mode of MODES) → test.each([...MODES])

Loops left alone (per the documented exceptions)

• Cleanup/teardown loops (env restoration, mock restoration, temp-dir removal).
• Runtime-data assertions (e.g. http.requests collected during the test, files map captured from a callback).
• Mathematical iteration that is the property being asserted (pkce rejection-sampling distribution).
• Setup loops creating fixture files.

Test plan

• bun run typecheck — passes
• bun run lint — 0 warnings, 0 errors
• bun run format:check — clean
• bun run test on the 7 touched files — 217/217 pass
• Full bun run test — 1406 pass, 122 fail; the 122 failures are preexisting on main and unrelated to this diff (verified via git stash baseline)
• bun run test:e2e:op — not run locally; CI will exercise

[changeset-bot]

⚠️ No Changeset found

Latest commit: e89546e

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: b02c8983-30b6-4487-b71b-70a8247faa23

📥 Commits

Reviewing files that changed from the base of the PR and between 04baa3f and e89546e.

📒 Files selected for processing (8)

• .claude/rules/testing.md
• packages/cli-core/src/cli-program.test.ts
• packages/cli-core/src/commands/init/bootstrap.test.ts
• packages/cli-core/src/commands/skill/install.test.ts
• packages/cli-core/src/lib/listage.test.ts
• packages/cli-core/src/lib/users.test.ts
• packages/cli-core/src/test/integration/onboard.test.ts
• packages/cli-core/src/test/integration/switch-apps.test.ts

✅ Files skipped from review due to trivial changes (1)

• .claude/rules/testing.md

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📝 Walkthrough

Walkthrough

This PR replaces manual in-test loops with parameterized test.each across documentation, unit tests, and integration tests. It adds a testing convention doc explaining the rule, a typing workaround for readonly/as const arrays, and exceptions where loops are acceptable. The pattern is applied to several unit tests (cli-program, bootstrap, skill/install, listage, users) and two integration tests (onboard, switch-apps), preserving existing assertions and test behavior.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main objective: converting test loops to test.each across the test suite.
Description check	✅ Passed	The description comprehensively explains the changes, including the new convention, files refactored, exceptions documented, and test results.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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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