On the NetTuts.com site today there's a new tutorial introducing the Hamcrest validation matchers and how to use them in your PHPUnit testing to enhance both the readability and functionality of the assertions.

Hamcrest is a set of matchers for writing more expressive code. It just so happens that these matchers are especially useful when writing tests. In this article, we'll look at Hamcrest for PHP. [...] Hamcret's expressiveness originated with JMock, but it wasn't until the addition of the unique assertThat() method that it was refactored into a self-contained library and independently usable in testing frameworks.

He talks about the "generations" of unit testing tools, a division based on their assertion functionality - simple, exact or using matchers. Installation instructions via PEAR are included (though there's also a composer package for it too) as well as code for an example test. More samples are given for comparing things like numeric values, strings and setting up inclusions and exclusions with the anyOf/noneOf matchers.