webapp-testing

name	webapp-testing
description	Use when: test a web app across unit, integration, and end-to-end layers with the right balance.

Goal: cover behavior at the cheapest layer that proves it.

Use for:

• adding tests to a web app or feature
• deciding what to unit test vs. integration vs. e2e
• replacing brittle tests that break on refactors

Workflow:

1. Identify the behavior and its user-visible contract.
2. Choose the lowest layer that can verify it honestly.
3. Unit test pure logic; integration test wiring; e2e the critical paths.
4. Set up real dependencies where feasible; mock only true boundaries.
5. Make tests deterministic: control time, network, and data.
6. Run, confirm meaningful failure, then keep green.

Layer guidance:

• unit: pure functions, reducers, validation
• integration: components with real children, API handlers with a real db
• e2e: signup, checkout, and other revenue-critical flows

Rules:

• test behavior, not implementation detail
• do not mock what you are trying to verify
• keep e2e few and high-value; they are slow and flaky-prone
• a test that never fails has no value