I don't know where you get your information, buzzcutbuddha,
but I was writing tests before functions and unit testing
my pieces long, long before I'd heard of "Extreme" anything.
XP may advocate these practices, but it is not their origin.
I had not heard of Unit Testing prior to reading about Extreme Programming, and so many XP advocates tout that as one of their strengths that I made an assumption, which as we all now, is a Bad Thing. I should have known better.