Theo Kouzelis has a recent tutorial posted showing you how to make your PHPUnit tests a bit cleaner with the help of data providers, a built-in tool for PHPUnit that allows for easier validation of larger datasets.

When writing tests I try to describe the test in the function name. I use the format testDoesSomethingWhenPassedSomething to first describe the assertion and then the context. [...] When I have many data sets running against the same test I will use the frameworks data providers to make the code less verbose.

He includes code examples to show both the difference between the single data tests and one using a set of email addresses to validate their correctness. He notes that the error message using data providers can be confusing (and maybe hide the real problem) so he offers a solution to make it more readable: associative arrays. The trick is that PHPUnit uses the key to display the error and by making this unique you can make the error output more informative.