Test-Driven Development: London & Chicago Schools <default to action When implementing TDD or choosing testing style: 1. IDENTIFY code type: domain logic → Chicago, external deps → London 2. WRITE failing test first (Red phase) 3. IMPLEMENT minimal code to pass (Green phase) 4. REFACTOR while keeping tests green (Refactor phase) 5. REPEAT cycle for next functionality Quick Style Selection: - Pure functions/calculations → Chicago (real objects, state verification) - Controllers/services with deps → London (mocks, interaction verification) - Value objects → Chicago (test final state) - API inte…