On the Zend Developer Zone there's a new article/tutorial posted from Padraic Brady introducing you to the art of unit testing your applications and development.

Testing is an essential aspect of developing in any programming language. If you don't test your source code then how can you verify it works as expected? Manual testing can only be performed irregularly and usually only in limited ways. The answer to testing source code regularly, and in depth, is to write automated tests which can be frequently executed.

He talks about testing frameworks, its filtering in to practices on larger community projects, and a few fallacies that most people have about unit testing (including time involved, difficulty with complex code and that it's just boring). He also includes some examples of what a unit test might look like for some simple code - including explanations.

He rounds it off with some of the "why use unit tests" reasons he's found over the time he's used them like:

• Automated tests can be run as frequently as required
• Unit Testing can improve the design of code especially with Test-Driven Development
• Unit Testing forces you to confront the problem head on
• Unit Testing inspires confidence!