NestJS Testing Skill

Tech Stack

• Framework: NestJS with @nestjs/testing
• Testing Framework: Jest with ts-jest
• HTTP Testing: Supertest
• Mocking: @golevelup/ts-jest for deep mocking with createMock<T>()
• E2E Database: @testcontainers/postgresql for isolated database tests

Conventions

• Unit tests alongside source files: *.spec.ts
• E2E tests in test/ directory: *.e2e-spec.ts
• Use createMock<T>() from @golevelup/ts-jest for all mocking (type-safe deep mocks)
• Use beforeEach() for per-test setup, beforeAll()/afterAll() for e2e app lifecycle

Running Tests