sdcorejs-testing-e2e-nestjs

Write NestJS E2E tests by booting the full app with @nestjs/testing and executing requests via supertest against a real PostgreSQL database provisioned through testcontainers or pg-mem. This approach validates actual database semantics, transaction rollbacks, and endpoint behavior that unit tests miss.

Transaction rollback verification in NestJS E2E tests works by inducing a failure during a multi-table write operation and asserting that observable database state returns to its pre-request condition. It uses supertest to trigger the endpoint and checks the PostgreSQL database to confirm no partial writes persisted.

Yes, you can use testcontainers with supertest to test NestJS auth and permission flows by applying an auth fixture to validate AuthGuard and HasPermission decorators against a real PostgreSQL database. This setup accurately asserts 401 unauthorized and 403 forbidden outcomes per endpoint.

The best way to assert bilingual error messages in NestJS API responses is to validate the { vi, en } error payload shape returned by ZodValidationGuard-driven failures. Use supertest to trigger 422 unprocessable entity or 409 duplicate domain errors and assert both language fields are present.

NestJS E2E tests fail when running concurrently with testcontainers due to shared PostgreSQL database state conflicts. Ensure reliable E2e execution by using the Jest --runInBand reliability guardrail in your jest-e2e config to serialize test runs and prevent parallel database interference.