Agent Skills: Integration & Contract Testing

Integration & Contract Testing

Focused patterns for testing API boundaries, cross-service contracts, component integration, database layers, property-based verification, and schema validation.

Quick Reference

For complex emulate setups (full config generation, webhook HMAC, CI per-worker port isolation), delegate to the emulate-engineer subagent. Pairs with the emulate-seed skill.

| Area | Rule / Reference | Impact | |------|-----------------|--------| | Stateful API testing (emulate) | rules/emulate-stateful-testing.md | HIGH | | API endpoint tests | rules/integration-api.md | HIGH | | React component integration | rules/integration-component.md | HIGH | | Database layer testing | rules/integration-database.md | HIGH | | Zod schema validation | rules/validation-zod-schema.md | HIGH | | Pact contract testing | rules/verification-contract.md | MEDIUM | | Stateful testing (Hypothesis) | rules/verification-stateful.md | MEDIUM | | Evidence & property-based | rules/verification-techniques.md | MEDIUM |

References

| Topic | File | |-------|------| | House rules not documented upstream | references/ork-delta.md | | Consumer-side Pact tests | references/consumer-tests.md | | Hypothesis strategies guide | references/strategies-guide.md |

Checklists

| Checklist | File | |-----------|------| | Contract testing readiness | checklists/contract-testing-checklist.md | | Property-based testing | checklists/property-testing-checklist.md |

Scripts & Templates

| Script | File | |--------|------| | Create integration test | scripts/create-integration-test.md |

Examples

| Example | File | |---------|------| | Full testing strategy | examples/orchestkit-test-strategy.md |

Upstream coverage (do not restate)

This skill wraps Pact, the Pact Broker, and FastAPI testing. It carries only the OrchestKit delta. Fetch the vendor docs for the topics below instead of restating them here.

| Topic | First-party source | |-------|--------------------| | Pact Broker publish CLI, pact versioning and tagging flags | https://docs.pact.io/pact_broker/publishing_and_retrieving_pacts | | can-i-deploy, record-deployment, record-release | https://docs.pact.io/pact_broker/can_i_deploy | | Deployment and release recording semantics | https://docs.pact.io/pact_broker/recording_deployments_and_releases | | Broker webhooks that trigger a provider build on contract change | https://docs.pact.io/pact_broker/webhooks | | Consumer version selector syntax (mainBranch, deployedOrReleased, matchingBranch) | https://docs.pact.io/pact_broker/advanced_topics/consumer_version_selectors | | Pending pact semantics | https://docs.pact.io/pact_broker/advanced_topics/pending_pacts | | Provider state setup hooks and state endpoint wiring | https://docs.pact.io/getting_started/provider_states | | FastAPI TestClient and dependency_overrides for a test database | https://fastapi.tiangolo.com/advanced/testing-dependencies/ | | GitHub Actions job ordering (needs:) and branch filters | https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions | | QA test-plan paperwork (schedule, roles, defect lifecycle, sign-off tables) | Tracker-owned; no single vendor page covers all four. Defect lifecycle: https://docs.github.com/en/issues/tracking-your-work-with-issues/about-issues . Schedule, roles and sign-off are org process, not a documented product feature. House quality budgets from the retired template survive in references/ork-delta.md |

The house subset of those topics stays in this skill and is not routed away: rules/verification-contract.md keeps the two broker commands ork gates on plus the selector defaults; checklists/contract-testing-checklist.md keeps the CI/CD, isolation and security checkboxes; references/consumer-tests.md keeps the business-language provider-state naming convention and the matcher table. The rules that have no upstream home at all live in references/ork-delta.md.

Stateful API Testing (emulate — FIRST CHOICE)

For GitHub, Vercel, and Google API integration tests, emulate is the first choice. It provides full state machines that model real API behavior — not static mocks.

| Tool | Best For | |------|----------| | emulate | Stateful API tests (GitHub/Vercel/Google) — FIRST CHOICE | | Pact | Cross-team contract verification | | MSW | Frontend HTTP mocking (simple request/response) | | Nock | Node.js unit-level HTTP interception |

See rules/emulate-stateful-testing.md for the full decision matrix, seed-start-test-assert pattern, and incorrect/correct examples.

Testcontainers (real dependencies in CI)

When contract tests and emulate aren't enough — e.g. testing against real Postgres, Redis, Kafka, or an S3-compatible store — Testcontainers spins up ephemeral Docker containers per test and tears them down afterward. path_patterns above already matches **/testcontainers/**; use these patterns there.

Target: testcontainers >= 11.0.0 (Node) — v11 (Q1 2026) added named-network auto-cleanup, reusable containers via .withReuse(), and first-class Podman support.

Node.js (testcontainers-node)

import { PostgreSqlContainer } from '@testcontainers/postgresql'
import { describe, beforeAll, afterAll, test, expect } from 'vitest'

describe('UserRepository integration', () => {
  let container: Awaited<ReturnType<PostgreSqlContainer['start']>>
  let repo: UserRepository

  beforeAll(async () => {
    container = await new PostgreSqlContainer('postgres:16-alpine')
      .withDatabase('test')
      .withUsername('test')
      .withPassword('test')
      .withReuse()  // v11+ — reuse across runs to speed CI
      .start()

    repo = new UserRepository(container.getConnectionUri())
    await repo.migrate()
  }, 30_000)

  afterAll(async () => {
    await container.stop()
  })

  test('persists and retrieves a user', async () => {
    const created = await repo.create({ email: 'a@b.c' })
    const found = await repo.findById(created.id)
    expect(found?.email).toBe('a@b.c')
  })
})

Python (testcontainers-python)

from testcontainers.postgres import PostgresContainer
import pytest

@pytest.fixture(scope="session")
def postgres():
    with PostgresContainer("postgres:16-alpine") as pg:
        yield pg.get_connection_url()

def test_user_repo(postgres):
    repo = UserRepository(postgres)
    repo.migrate()
    user = repo.create(email="a@b.c")
    assert repo.find_by_id(user.id).email == "a@b.c"

Decision matrix:

| Scenario | Pick | |----------|------| | Third-party API (GitHub, Vercel, Google) | emulate | | Cross-team API contract | Pact | | Real Postgres / Redis / Kafka integration | Testcontainers | | Just mocking HTTP in a frontend test | MSW |

Quick Start: API Integration Test

TypeScript (Supertest)

import request from 'supertest';
import { app } from '../app';

describe('POST /api/users', () => {
  test('creates user and returns 201', async () => {
    const response = await request(app)
      .post('/api/users')
      .send({ email: 'test@example.com', name: 'Test' });

    expect(response.status).toBe(201);
    expect(response.body.id).toBeDefined();
    expect(response.body.email).toBe('test@example.com');
  });

  test('returns 400 for invalid email', async () => {
    const response = await request(app)
      .post('/api/users')
      .send({ email: 'invalid', name: 'Test' });

    expect(response.status).toBe(400);
    expect(response.body.error).toContain('email');
  });
});

Python (FastAPI + httpx)

import pytest
from httpx import ASGITransport, AsyncClient
from app.main import app

@pytest.fixture
async def client():
    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as ac:
        yield ac

@pytest.mark.asyncio
async def test_create_user(client: AsyncClient):
    response = await client.post(
        "/api/users",
        json={"email": "test@example.com", "name": "Test"}
    )
    assert response.status_code == 201
    assert response.json()["email"] == "test@example.com"

Coverage Targets

| Area | Target | |------|--------| | API endpoints | 70%+ | | Service layer | 80%+ | | Component interactions | 70%+ | | Contract tests | All consumer-used endpoints | | Property tests | All encode/decode, idempotent functions |

Key Principles

1. Test at boundaries -- API inputs, database queries, service calls, external integrations
2. Fresh state per test -- In-memory databases, transaction rollback, no shared mutable state
3. Use matchers in contracts -- Like(), EachLike(), Term() instead of exact values
4. Property-based for invariants -- Roundtrip, idempotence, commutativity properties
5. Validate schemas at edges -- Zod .safeParse() at every API boundary
6. Evidence-backed completion -- Exit code 0, coverage reports, timestamps

When to Use This Skill

• Writing API endpoint tests (Supertest, httpx)
• Setting up React component integration tests with providers
• Creating database integration tests with isolation
• Implementing Pact consumer/provider contract tests
• Adding property-based tests with Hypothesis
• Validating Zod schemas at API boundaries
• Planning a testing strategy for a new feature or service

Related Skills

• ork:testing-unit — Unit testing patterns, fixtures, mocking
• ork:testing-e2e — End-to-end Playwright tests
• ork:emulate-seed — Seed configuration authoring for emulate providers
• ork:database-patterns — Database schema and migration patterns
• ork:api-design — API design patterns for endpoint testing