I've been resisting testing frameworks for a long time. I tend to test by using (and apparently being adept at writing relatively bug-free code), but one place tests provide true value is when modifying code.

I'm reworking the internals of aspects of Breve and I realized that I needed to do more than run visually inspecting the output of the included examples (I also test by deploying trunk onto the breve site and this blog prior to releases, but since I don't necessarily exercise all aspects of Breve, this is only a feel-good test).

Anyway, part of the daunting task of testing a template engine is that you must test against literal chunks of HTML. I decide to see what Genshi does, since whether I like that engine or not, it is the 900lb gorilla of Python template engines, and I know Chris Lenz and his cohorts have put a lot of effort into having a solid development process.

I took a look at Genshi's test suite and it was enough to get me started, although I wasn't thrilled about the tests having the expected output embedded directly in the tests. It seemed a bit cluttered and I knew it would get more cluttered as I implemented tests for corner cases (nesting of directives, inheritance, and combining features to check for side-effects).

I hacked about for a bit and came up with a system that seems to be working pretty well.

If you've been avoiding Breve because you're loathe to use software that doesn't include a test suite, you are now encouraged to look again.