integration-e2e-testing
Integration and E2E Testing Principles
References
E2E test design: See references/e2e-design.md for UI Spec-driven E2E test candidate selection and browser test architecture. The reference uses Playwright as the default browser harness; substitute the project's standard when different.
Test Type Definition and Standard Budgets
| Test Type | Purpose | Scope | External Deps | Standard Budget per Input Design Doc | Implementation Timing |
|---|---|---|---|---|---|
| Integration | Verify component interactions in-process | Partial system integration (in-process modules; for UI components, the framework's in-process renderer e.g., RTL+MSW for React/TS) | Mocked or in-process | MAX 3 | Created alongside implementation |
| fixture-e2e | Verify UI behavior in a browser with deterministic fixtures | Full UI flow with mocked backend / fixture-driven state | Mocked / fixture only — no live services | MAX 3 | Created alongside the UI feature |
| service-integration-e2e | Verify critical user journeys against a running local stack | Full system across services | Live local services or stubs | MAX 1-2 | Executed only in the final phase |
Lane selection (E2E only):
- Default lane for user-facing UI journeys is fixture-e2e — it runs a real browser against deterministic fixtures, catches the bugs that unit/integration tests miss (button no-op, state never updates, navigation breaks), and runs in CI without infrastructure setup
- Add service-integration-e2e only when the journey's correctness depends on real cross-service behavior (data persistence, transactional consistency, external service contracts) that cannot be faked safely
One input Design Doc is one budget scope: apply each lane budget once across all ACs and candidates in that document. The two E2E lanes are budgeted independently — having a fixture-e2e for a journey does not consume the service-integration-e2e budget and vice versa. Treat the numbers above as enforced standard budgets. Exceed a budget only when an accepted requirement or a distinct failure mode cannot be proved by a selected test; annotate that exception and why consolidation cannot cover it.