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In this screencast, we'll build a relatively simple class, using TDD techniques. Along the way, we'll discuss various PHPUnit methods, how to create mock objects, and more! I encourage you to work along; it's the best way to learn!
As with anything, there are various ways to approach test-driven development. Like they say, it doesn't matter as much how you test, as long as you are testing. If you have a different approach, let us know in the comments. I'd love to learn more!