The NetTuts.com site (well, TutsPlus) has posted a new tutorial that gets you more intimate with PhpSpec, a PHP-based testing tool that lets you define tests as specifications and using behavior-driven development principles. If you need an introduction to the tool, check out this other tutorial first.

If you compare PhpSpec to other testing frameworks, you will find that it is a very sophisticated and opinionated tool. One of the reasons for this, is that PhpSpec is not a testing framework like the ones you already know. Instead, it is a design tool that helps describing behavior of software. A side effect of describing the behavior of software with PhpSpec, is that you will end up with specs that will also serve as tests afterwards. In this article, we will take a look under the hood of PhpSpec and try to gain a deeper understanding of how it works and how to use it.

They provide a quick overview of some of the internals of the PhpSpec tool and a brief look at the difference between BDD (behavior-driven) and TDD (test-driven) development practices. There's also a look at how the tool differs from the popular PHP testing tool PHPUnit. Code examples are provided through out the post with simple tests, making the separation between the methods and tools easier to follow.