Escrever bons testes — que sejam confiáveis, manteníveis e valiosos — segue as melhores práticas estabelecidas. Testes ruins (frágeis, lentos, pouco claros) se tornam um fardo, enquanto bons testes fornecem valor duradouro. Compreender essas práticas é importante para testes eficazes.
Características de bons testes (FIRST)
FAST → run quickly (so they're run often)
INDEPENDENT/ISOLATED → don't depend on each other or order; each sets up its own state
REPEATABLE → same result every time, any environment (no flakiness)
SELF-VALIDATING → clear pass/fail (assertions, not manual inspection)
TIMELY → written with (or before) the code
Práticas-chave
✓ Test BEHAVIOR, not implementation → tests survive refactoring (don't test internals)
✓ ONE concept per test → focused tests; clear what failed when one breaks
✓ CLEAR NAMES — describe what's tested ("returns error when email is invalid")
✓ Arrange-Act-Assert structure → readable, organized
✓ Cover EDGE cases and error conditions (not just the happy path)
✓ Keep tests SIMPLE and readable (tests are documentation; avoid complex logic in tests)
✓ DETERMINISTIC — no reliance on time, randomness, external state, or order (avoid flaky)
✓ DRY but readable — share setup (fixtures), but keep each test clear on its own
