Integration Testing

Integration tests verify that multiple components work together correctly.

Differences from Unit Tests

• Integration tests exercise interactions across modules or services.
• They are slower and require controlled environments.

Designing Integration Tests

• Use fixtures to start/stop services (databases, web servers).
• Seed test data and clean up after tests.

Example (conceptual)

A test might start a test database, run a function that writes data, then query the database to assert the end-to-end behavior.

Gotchas

• Avoid running slow integration tests repeatedly; separate them in CI.
• Networked services add flakiness — use local test doubles or containers.