Phly, boy, phly
the weblog and site of Matthew Weier O'Phinney

As promised in my earlier entry from today, here's my quick-and-dirty tutorial on unit testing in PHP using phpt.

First off, phpt test files, from what I can see, were created as part of the PHP-QA effort. While I cannot find a link within the PHP-QA site, they have a page detailing phpt test files, and this page shows all the sections of a phpt test file, though they do not necessarily show examples of each.

Also, you might find this International PHP Magazine article informative; in it Aaron Wormus gives a brief tutorial on them, as well as some ways to use phpt tests with PHPUnit.

Finally, before I jump in, I want to note: I am not an expert on unit testing. However, the idea behind unit tests is straightforward: keep your code simple and modular, and test each little bit (or module) for all types of input and output. If the code you're testing is a function or class method, test all permutations of arguments that could be passed to it, and all possible return values.

Okay, let's jump in!

I've been tinkering with Unit Testing for around a year now, and have tried using PHP Unit as well as Simple Test. It was while following the Simple Test tutorial that I finally grokked the idea of unit testing, and so that has been my favored class for testing.

However, I find writing the tests tedious. In Simple Test, as in PHP Unit, you need to create a class that sets up the testing harness, and then you create a method for each test you wish to run, and so on... I found it incredibly time consuming. Additionally, I found the test harness often felt like a foreign way of testing my code; I was setting up a structure I would never use my code in, typically. All in all, I only test when I have extra time (which is rare) or when I'm really having trouble nailing down bugs (and the unit tests often don't help me find them).

Recently, I've been hearing some buzz over on the PEAR lists and the blogs of some of its developers about 'phpt' tests. From what I hear, phpt tests sound very similar to how one tests in perl (though I've never written perl tests, I've at least glanced through them). However, until recently, I haven't seen any documentation on them, and installing PEAR packages via pear doesn't install tests.

We got a copy of PHP5 Power Programming a few weeks ago, and in the section on preparing a PEAR package was a brief section on phpt tests. The section was small, and when I looked at it, my immediate thought was, "it can't be that simple, can it?"

So, I decided to try it out with Cgiapp. A few minutes later, I had some working tests for my static methods. "Hmmm," I thought, "That was easy. Let's try some more."

Turns out they're kind of addictive to geeks like me. In a matter of a few hours, I'd knocked out tests for over half the functionality, and disccovered, to my chagrine and joy, a number of bugs and bad coding practices... which I promptly corrected so I could get that magical 'PASS' from the test harness.

In the process of writing the tests, my understanding of the tool evolved quite a bit, and by the end, I had the knack for it down. I'll blog later about some of the ways I made them easier to use for myself -- and how I made them more useful for debugging purposes.