More and more talk is being given to testing applications these days. For some, that just means going through the functionality and ensuring that things seem to be working okay. That's one way to find problems in an application, but not the best way. A better way it through unit testing, a system of writing up various tests for the functions making up your application to ensure they're 100% working. Not familiar with it? That's what this new tutorial from DevShed is for - another excerpt from the Sams Publishing book "Advanced PHP Programming".

All code is tested at some point—perhaps during its implementation, during a dedicated testing phase, or when it goes live. Any developer who has launched broken code live knows that it is easier to test and debug code during development than after it goes into production.

Unit testing helps with finding these problems before they get into the hands of live users. The tutorial gives you a basic overview of how to work with this handy tool, specifically with the PHPUnit package. They help you write a simple test, expand on this base with more elaborate tests, and how to package your tests right in with your libraries to make installation/packaging simpler.