testing-guide-nestjs-project

NestJS testing requires a structured strategy across unit, integration, and e2e levels that respects dependency injection and architectural rules. This guide provides artifact-specific patterns for services, controllers, modules, guards, and middleware to align teams on repeatable practices.

Testing NestJS services and controllers requires defined mock boundaries and correct dependency injection rules. This guide supplies ready-made patterns and references to implement and review tests consistently across project artifacts using real libraries and mock strategies.

NestJS integration testing can use a real PostgreSQL database to reproduce production-like conditions. This guide enables realistic test environments by documenting setup patterns, dependency injection rules, and cross-cutting concerns like authentication and email integration.

Testing NestJS cross-cutting artifacts like guards, pipes, interceptors, and filters requires artifact-specific guidance to avoid regressions. This guide covers established testing foundations and references common pitfalls and gotchas specific to these components.

NestJS test suites fail when dependency injection rules are not respected during test setup. This guide addresses common testing pitfalls and gotchas by providing documented setup patterns and mock boundaries to prevent architectural regressions.