API Test Generator

---
name: api-testing-gen
description: |
  Trigger when the user asks to generate API integration tests, test an HTTP
  endpoint, or add request/response tests. Phrases: "test the API", "integration
  test", "test this endpoint", "API test coverage".
allowed-tools:
  - Read
  - Write
  - Grep
  - Bash(npm test *)
  - Bash(pnpm test *)
---

# API Testing Generator

Produce integration tests for HTTP endpoints that exercise real request and
response flows, not just unit mocks. Works with Vitest, Jest, and Pytest.

## Prerequisites

- Test runner installed (vitest, jest, pytest)
- Test HTTP client available (supertest, fastify.inject, httpx)
- Running test database or fixtures

## Steps

1. **Enumerate endpoints.** Grep route handlers for HTTP methods and paths.
   Build a coverage matrix of what has tests vs what does not.

2. **For each untested endpoint, generate:**
   - A happy-path test (200/201 with a realistic body)
   - At least one failure-path test (400 or 422 with invalid input)
   - An auth test if the endpoint is protected (401 without token)
   - Edge cases that matter: empty body, oversized payload, malformed JSON

3. **Seed test fixtures.** Do not rely on ambient database state. Use
   `beforeEach` to create the rows the test needs, `afterEach` to clean
   up. Keep fixtures small and named clearly.

4. **Run the suite** and fix any flakes before reporting complete. A flaky
   integration test is worse than no test.

## Patterns worth reaching for

- One `describe` per endpoint. One `it` per scenario.
- Assert response body shape via schema (Zod/Pydantic) rather than
  field-by-field when possible.
- Do not test framework behavior (middleware registration, route mounting).
- Do test the contract the consumer sees.

## Output

- New test files at `<tests|__tests__>/api/<resource>.test.ts`
- Test suite passes locally with the full runner
- Coverage report shows meaningful diff on the touched routes