Test Driven Development with PHPUnit
TDD is the future of web development. As web programming languages gain more functionality and become more advanced we as web developers must change the way we program/think.
Test driven development ( PHPUnit ) is one of those things that come around and you wonder how you ever programmed without it.
Check it out!
"Even good programmers make mistakes. The difference between a good programmer and a bad programmer is that the good programmer uses tests to detect his mistakes as soon as possible. The sooner you test for a mistake the greater your chance of finding it and the less it will cost to find and fix."
[PHPUnit Manual Excerpt]