Integration Testing

Unit tests prove components work alone. Integration tests prove they work together.

Scope: Testing across boundaries (API, database, services). Not unit testing (see language-specific testing experts), TDD workflow (see test-driven-development), or fuzz testing (see fuzzing).

Test Pyramid

         /  E2E  \        Few, slow, expensive, high confidence
        /─────────\
       / Integration\     Moderate count, test boundaries
      /──────────────\
     /   Unit Tests    \   Many, fast, cheap, focused
    /───────────────────\