Typescript testing backend

Skill LazyIsEfficient/agentic-os/.claude/skills/typescript-testing-backend

Use when writing or reviewing TypeScript backend tests — Jest unit tests for services/controllers (mocked Prisma) or Supertest integration tests against a real isolated PostgreSQL test database. Triggers on edits to `*.service.test.ts`, `*.controller.test.ts`, `*.integration.test.ts`, service/controller/API test files (`.ts`, not `.tsx`) under `**/__tests__/`, or mentions of "backend test", "service test", "API test", "database test".From its SKILL.md

Install

npx -y skills add LazyIsEfficient/agentic-os --skill typescript-testing-backend

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

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SKILL.md

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TypeScript Testing — Backend

You are operating as a backend test engineer. Mock at the module edge for units, hit a real Postgres for integration, and never assert on internal call shapes.

Reference stack: Jest 29 with @swc/jest, Supertest for HTTP, a custom TestServer helper that simulates Next.js route handlers, and a TestDatabase helper that provisions isolated PostgreSQL instances per run with migrations + seed. Tests live co-located in __tests__/ folders.

Unit tests mock the Prisma client at the module boundary; integration tests use the real DB plus an auth-state helper for authenticated request flows.

Universal Rules

Use Jest — jest.mock() / jest.fn(), never vi.*.
Co-locate tests in __tests__/ next to the source.
Mock at the module boundary — not internal functions.
Literal expected values — expect(total).toBe(70), never expressions.
Every it() asserts observable behavior with at least one expect().
beforeEach cleanup, scoped to test-created records — never truncate seed data.
Clear auth/state helpers between tests so authenticated flows don't bleed across cases.
Never test.skip() — fix or delete.
Real DB for integration tests, mocked Prisma for unit tests.
Internal utils stay real — only mock external boundaries.

References

references/framework-and-structure.md — Jest config, test scripts, directory layout, file naming conventions, coverage
references/unit-testing.md — service unit tests with mocked Prisma, controller unit tests with injected service mocks
references/integration-testing.md — shared setup, full Supertest example, TestServer pattern, authTestHelpers API
references/database-testing.md — setupTestDatabase, isolated DBs, cleanup rules, accessing seeded data
references/mock-policy-and-quality.md — mock scope table, quality criteria, test failure triage

What ships with it: 5 files

9.4 KB alongside SKILL.md