Instructor Notes

Note: Final code is in the solution branch, refer to the individual commits for the order of things

Intro

Go over the history and motivations behind TDD
- Tests as documentation
- Preventing over-engineering
- Easier refactoring, preventing regressions
Red, Green, Refactor
Mention feature testing, but this lab won't go into it

Explain rspec init, point out random order in config file
Do Rectangle initialization and perimeter as a code-along
Do Rectangle area as a lab, then demo solution and introduce before
Do Circle as a lab, pointing to RSpec docs to find matchers
Demo solution for Circle and explain before vs. let
Do Triangle as a lab, giving the option to proceed to the bonuses
Demo solution for Triangle
Demo bonus for Triangle, introducing error matchers and refactoring with private method