test-driven-development

# Test-Driven Development ## Overview TDD uses the **Red → Green → Refactor** micro-cycle. First, define expected behavior. Next, use a minimal implementation to pass the test. Finally, organize the code structure. ## When to Use - Adding or modifying core logic. - Fixing bugs and needing regression protection. - Requirements can be written as explicit input/output acceptance tests. ## Workflow 1. **Red**: Write a failing test describing the expected behavior. 2. **Green**: Write the minimal code to make the test pass. 3. **Refactor**: Clean up naming, structure, and duplication. 4. Repeat the cycle until acceptance criteria are met. ## Ironclad Rules - Do NOT write massive amounts of features before writing tests. - Focus on one small goal per cycle. - All tests MUST pass after refactoring.