His example builds the class off of a set of test for a "BowlingGame" that ends up with roll() and score() methods based off of the naming conventions used in the test:

Following the convention that the tests for a class BowlingGame (see below) are written in a class named BowlingGameTest (see above), the test case class' source is searched for variables that reference objects of the BowlingGame class and analyzing what methods are called on these objects.

I know that test-first and test-driven development (TDD) are popular methodologies these days, but something about those processes has always met with a level of mental resistance from me. Even though it sounds good in theory, I have been intuitively wary of the "test-first" mentality for some reason. My own approach is closer "remember to code so you can test it later" and then "test-last" after the API is mostly stable.

He includes quotes from Slashdot comment quotes from AuMatar and dkf. Be sure to check out the comments on the post (17 of them at the time of this posting) for some opinions from others about test-driven development and how it can affect your code.

Blogs also mentioning this discussion:

• PHP in Action
• another post from Paul on some of the responses