TDD

The mentor assesses your TDD proficiency level, then guides you through Red-Green-Refactor cycles where you write a failing test, make it pass with minimal code, and refactor. You stay at the keyboard while the mentor narrates or coaches based on your level.

Red means writing the smallest failing test, Green means writing the simplest code that makes it pass, and Refactor means cleaning up the code while keeping tests green. The cycle repeats in small 5-10 minute loops until the feature is complete.

Use TDD when requirements are clear and you need proof each step works. Use BDD when the feature shape is unclear and needs scenario clarification first, and spike-then-refactor when exploring unfamiliar territory.

A test that passes immediately means the Red phase was skipped, indicating the test is wrong or the code already exists. The mentor protocol flags this as an anti-pattern and asks you to verify what the test actually checks.

Proficiency is recorded as Novice, Familiar, Competent, or Proficient in a progress file under method_proficiency.TDD. Progression signals include naming phases yourself, completing cycles independently, and refactoring confidently.