SaaS - 5.2 - FIRST, TDD and getting started with RSpec

Introduction

Features of Unit tests

Fast: Run tests quickly
Independent: No tests depend on other. So can run any subset of the tests in any order.
Repeatable: Run N times and get the same result.
Self-checking: Test can automatically detect if passed. No human checking of output should be required.
Timely: Written about the same time as the code under test.