PHPUnit is such a tool. It supports the development of object-oriented PHP applications using the concepts and methods of Agile Programming, Extreme Programming, Test-Driven Development, and Design-by-Contract Development by providing an elegant and robust framework for the creation, execution, and analysis of unit tests.
The release of PHP 5 in July 2004 marked a significant leap in PHP's evolution--it enabled the development of large-scale applications to leverage the productivity, maintainability, and reusability of object-oriented design. While the language features introduced in PHP 5 are vital for this, the development of large-scale applications requires additional tools and techniques to be viable.
This article introduces you to the framework, shows you how to create a simple test with it (including some configuration), and working with the "fixture" of the test. If you're interested in getting into unit testing your scripts, this article is a good place to start...
