api-testing

API Integration Testing

Build robust test suites for your APIs with integration, contract, and E2E tests.

Testing Pyramid for APIs

Level	What It Tests	Speed	Isolation
Unit	Handlers, validators, utils	Fast	High
Integration	API + database, services	Medium	Medium
Contract	API shape vs OpenAPI spec	Fast	High
E2E	Full stack, real DB	Slow	Low

Key Principles

• Test API behavior through HTTP requests, not internal function calls
• Use real database for integration tests (SQLite or test containers)
• Validate response shapes against OpenAPI spec with contract tests
• Isolate external services with MSW or similar mock servers

Quick Start Checklist

1. Set up test framework (Vitest + Supertest recommended)
2. Configure test database (separate from dev)
3. Create test factories for data setup
4. Write integration tests for each endpoint (happy + error paths)
5. Add contract tests against OpenAPI spec
6. Configure CI pipeline for automated test runs

References

Reference	Description
test-frameworks.md	Vitest, Jest, Supertest setup and configuration
test-patterns.md	Request testing, authentication, error validation
test-data.md	Factories, fixtures, database seeding
contract-testing.md	OpenAPI validation, schema testing
ci-cd.md	CI pipeline configuration, environment setup