testing

name	testing
description	Meaningful testing strategy and coverage guardrails
user-invocable	true

Testing Skill

Testing guidance focused on durable behavior and maintainable feedback loops.

Core Principles

• Tests protect durable contracts, invariants, and failure modes.
• Prefer tests that still matter after refactors, removals, and package moves.
• Coverage informs risk; it is not a target to game.

Choose the Right Test Level

• Unit tests: deterministic domain logic, pure transformations, validation rules.
• Integration tests: seams between transport, domain, storage, and adapters.
• End-to-end tests: critical user/system paths only.
• During architecture-first refactors, favor seam/integration coverage around stable contracts before cutover.

Test-First Guidance (Not Ceremony)

• Prefer test-first when it clarifies behavior or de-risks implementation.
• For large refactors or testability seam setup, it is acceptable to reshape code first, then add or adjust tests before declaring the change done.
• Do not create ceremonial failing tests for behavior intentionally removed.
• When behavior is removed, delete stale tests and replace them only with tests for the new intended contract.

Durable Assertion Heuristics

• Start with a user-visible contract: what should render, enable, redirect, or block.
• Prefer positive assertions (contains, state transitions, status, links) over absence assertions.
• Use negative assertions only for explicit invariants (security/privacy/protocol/mutual exclusion).
• Every allowed negative assertion should include an adjacent rationale.