Digital Digressions by Stuart Sierra
From programming to everything else
I once saw a TV show about competing groups of archeologists trying to demonstrate how the ancient Egyptians raised stone obelisks weighing hundreds of tons. One group of archeologists built a complex apparatus involving a wooden frame and lots of rope. It looked impressive, but it didn’t work. The other team built a sand pit,…
I’ve been thinking a lot about testing frameworks over the past six months, and I’m not the only Stuart doing that. Stuart Halloway, who spent some time on his own Clojure testing framework, Circumspec, recently wrote about his experiences refactoring some of the language tests included with Clojure. One of Stu’s first points is that…
A couple of weeks ago I wrote about typed assertions for Lazytest. Like so many things, it seemed like a good idea at the time. Define typed objects for each kind of assertion (e.g., equality, instanceof). When a test fails, throw an exception with one such object as the payload. The type of the object…
One of my stated goals with Lazytest was to enforce a clean separation between test assertions and code that runs before/around the assertions. The Spock framework for Java/Groovy calls these the stimulus and response, identified by the keywords when and then, respectively. I find this approach attractive, but one look at Spock’s documentation shows it’s…
Following my last post I integrated typed assertions into the master branch of Lazytest. This makes some changes to the API. Test examples in the it macro can no longer simply return true or false. Instead, they must call the expect macro. The Context type is gone, replaced by the Fixture protocol. More documentation to…
One thing clojure.test did reasonably well was tell you why an assertion failed. Currently, Lazytest fails in this regard. The problem with requiring test functions to return true/false to indicate pass/fail is that they can’t attach any additional information to a failure to explain why it failed. I realized that function return values are insufficient…