Test how components work together — databases, APIs, and external services with realistic test environments.
Five passes over the same idea, each from a different angle. Do them in order, or jump to whichever you need.
Integration tests verify that multiple components work correctly together. They test real database queries, HTTP calls, and service interactions. Tools like Testcontainers, WebApplicationFactory (.NET), and supertest (Node.js) enable realistic test environments. Balance between unit test speed and end-to-end test realism.
