Recently, I’ve been coming across a few Perl projects (both at work, and in the wild) that are reasonably large and complex, have test suites, but don’t use Test::Class. And I really struggle to understand why. Most of them have decent test suites, at least in terms of coverage. But, personally, I have a hard time looking at the test files and understanding exactly what’s going on.

Most other widely used languages have at least one class-based testing framework that is the de-facto standard, usually based around xUnit. I find there are several benefits to using a framework like Test::Class:

As I mentioned, it makes your tests more readable by breaking them up into methods (I blogged a while ago about breaking them up even further for maximum readability). This ensures you’re clear about what you’re testing in every test, and you don’t get a really complex setup, used by a whole lot of different tests. Not only is that difficult to read, but it quickly becomes complex to maintain, and the tests become fragile, throwing you false negatives. Makes code-reuse easier, with inheritance (ok, so we all use roles now, but inheritance is still better than nothing). Makes it easy to setup fixtures by storing them in $self, using setup, teardown, etc. methods, all of which encourages more code-reuse Helps with test driven development, by allowing you two map one application class to one test class, or set of classes where necessary. You can do it with a bunch of .t scripts as well, I guess, but I usually find it easier with classes. And many more…!

We like to have a lot of options in Perl, and I’m fine with that, but you usually should have a good reason for deviating from the norm. So is Test::Class the norm (or did I just get a bad sample)? If it’s not the standard, why isn’t it? It seems to have a pretty thin set of dependencies, is stable and mature code, and fits right in with Test::Builder and friends.

In my opinion, you should use Test::Class unless you have a damn good reason not to!