Test Service Layer

Name: test:service-layer
Rating: 78
Author: edneyreis999

Testes para camada Application (DDD).

Regras

•INTEGRACAO prioritaria - unitario so se FakeBuilder + loop criar multiplos cenarios
•FakeBuilder OBRIGATORIO para inputs
•Mock apenas dependencias externas (DB, HTTP, eventos)
•Nomenclatura: *.integration.spec.ts (integracao) ou *.spec.ts (unitario)

Decisao Integracao vs Unitario

Cenario	Tipo
Fluxo completo com DB	Integracao
Multiplas variacoes de input	Unitario + loop
Validacao de orquestracao	Integracao

Padrao

typescript

describe('[UseCase]', () => {
  it('should [resultado] given [contexto]', async () => {
    const input = Entity.fake().anEntity().build();
    const result = await useCase.execute(input);
    expect(result).toMatchObject({...});
  });
});

Arvore de Decisao

code

Tem side-effect externo (DB, HTTP, evento)?
├─ SIM → INTEGRACAO
└─ NAO → Tem >3 variacoes de input?
         ├─ SIM → UNITARIO com loop + FakeBuilder
         └─ NAO → INTEGRACAO (mais valor)

Mocking Strategy

Dependencia	Mock?	Motivo
Repository	SIM (unit) / NAO (integ)	Testar persistencia real em integracao
External API	SEMPRE	Nao depender de servico externo
Domain Entity	NUNCA	Usar FakeBuilder
EventEmitter	SPY	Verificar emissao, nao mockar

Auto-Mocking (Preferido)

typescript

vi.mock('./repository');
vi.mocked(repository.save).mockResolvedValue(entity);

Evitar mock manual - usar vi.mock/jest.mock no nivel de modulo.

Estrutura de Arquivos

Testes DEVEM estar em __tests__/:

code

src/application/__tests__/list-entities.use-case.spec.ts

test.each para Search/Filter/Paginate

typescript

describe('search with filter and paginate', () => {
  const entities = [
    Entity.fake().anEntity().withName('test').build(),
    Entity.fake().anEntity().withName('TEST').build(),
    Entity.fake().anEntity().withName('TeSt').build(),
  ];

  const arrange = [
    { input: { page: 1, per_page: 2, filter: { name: 'TEST' } }, expected: { total: 3, current_page: 1 } },
    { input: { page: 2, per_page: 2, filter: { name: 'TEST' } }, expected: { total: 3, current_page: 2 } },
  ];

  beforeEach(() => repository.bulkInsert(entities));

  test.each(arrange)('when input is $input', async ({ input, expected }) => {
    const output = await useCase.execute(input);
    expect(output).toMatchObject(expected);
  });
});