In the practice of modern TDD two main schools of thoughts among TDD gurus have emerged. Let’s start by comparing the differing characteristics of each practice and present the key proponents of each approach. As a first oversimplification, we can broadly describe “classical TDD” as “bottom-up” and “london mockist” as top-down, as the name suggests mockist school relies on mock objects (actually doubles but who cares?) to test interactions on the unit level. read more