Test-Driven Development (TDD)

Overview

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

Core principle: If you didn't watch the test fail, you don't know if it tests the right thing.

When to use: Only for complex logic where bugs are likely, or when user explicitly requests tests.

When to Use

Use TDD when:

1. User explicitly requests tests
2. Complex logic where bugs are likely:
   • Complex algorithms
   • Business logic with edge cases
   • Data transformations