What to Test (Practical Checklist)

Use this as a lightweight checklist when adding or changing a feature.

For a new feature / workflow

Unit-level:
- formatters/parsers/normalizers (edge cases + failures)
- query key builders and “enabled” gating rules
Hook-level:
- hook outputs and state transitions
- error mapping / fallback values
Component-level (RTL):
- rendering contracts using role/name queries
- controlled input wiring (value + onChange)
- disabled and loading states
Contract/integration boundary:
- dialog orchestration: open/close + mutation wiring
- route behavior and redirect rules (if routing changes)
Error cases:
- API failure → user-friendly message and safe UI fallback
- empty results, null/undefined inputs, missing optional fields

Anti-patterns

Avoid: - flaky tests that depend on real time or async race conditions - over-mocking (mocking the unit under test instead of its boundaries) - testing implementation details (internal state shape, private helpers) - snapshot tests for dynamic UI (unless very stable and intentional)

Tips

Prefer asserting observable behavior:
- what is rendered
- which callbacks are called with which arguments
- what navigation is triggered
Keep i18n deterministic in tests by mocking react-i18next and using fallback strings.