test-driven-development

name	test-driven-development
description	Use when implementing any feature or bugfix, before writing implementation code

Test-Driven Development

Write the test first. Watch it fail. Write minimal code to pass. Refactor.

The Cycle

1. RED — Write one failing test for the behavior you want
2. Verify RED — Run it, confirm it fails for the right reason
3. GREEN — Write the simplest code to make it pass
4. Verify GREEN — Run it, confirm all tests pass
5. REFACTOR — Clean up, keep tests green
6. Repeat for next behavior

Rules

• No production code without a failing test first
• Write code before test? Delete it. Start over.
• One behavior per test, clear name, real code (not mocks)
• Minimal implementation — don't over-engineer

When stuck

Problem	Solution
Don't know how to test	Write the API you wish existed
Test too complicated	Design too complicated — simplify
Must mock everything	Code too coupled — use dependency injection