Michelangelo van Dam continues his "Quality Assurance in PHP projects" series in his latest post, the first of a few, about using PHPUnit to test your application.
Of all tools available for improving quality assurance, there's one tool that is the core tool you have to master: PHPUnit. PHPUnit is a complete testing framework crafted by Sebastian Bergmann (@s_bergmann), who ported existing xUnit frameworks to PHP. And with this testing framework you're able to test your functionality in an automated way before you push code into production.
Michelangelo walks you through the installation (via the PEAR installer), creating a phpunit.xml configuration file and making a basic bootstrapper to define some paths and environments. To make the tests a bit more relevant than just pseudo-test examples, he's created a set of tests based around a tic-tac-toe application in a test-driven design fashion (tests first, then code). In this first part he sets up some of his assertions in the tests, but you'll have to wait until part 2 for the code that will make them pass.