Essentially, Test-Driven Development (TDD) transforms your current process, while Approval Testing helps make up for it.
TDD is an efficient and effective process for delivering high quality code quickly, but it doesn't work when you're dealing with legacy code. Fortunately, Approval Testing is an excellent tool when you've got a program in production that doesn't have any automated tests.
In this session you'll get a quick introduction to TDD and Approval testing, when to use them, how they benefit you and others, and how they cover each other's weaknesses.