Forging on with javascript testing frameworks

I’ve got what I consider to be a decent set of unit tests in Chai, though I’m certainly a good deal away from a complete set. (As an aside, the inherently non-deterministic nature of js-weighted-list presents something of a testing challenge in itself, totally apart from the particular framework in use; I’ll have more to say about this in future.)  My impressions of it aren’t radically different from how I felt about it last time – I’m still not crazy about the syntax, but it has offered me one or two pleasant surprises when it found scope bugs I had missed.

There’s another  aspect of the framework I’ve enjoyed as well. As some background, I’m mostly investigating BDD frameworks, but I have to confess that I don’t really see how BDD is all that different from unit-test based testing, apart from the terminology in use; frankly the difference between a test suite and a spec doesn’t seem all that large to me, and I’m dubious about the vague claims of readability to non-programmers that seem to haunt the rhetoric of some BDD sites I’ve seen. But anyways, according to the classic BDD (or TDD) approach, I’m going about things backwards: I’m writing a suite of tests to cover code which already exists instead of starting with the tests and then writing code to satisfy them.

Certainly I’m not the first programmer in the history of the world to approach testing this way, but I did enjoy adding in some undefined specifications for a few missing features for the library and seeing them show up as elements in the list:

    it('should increase the length of the list');
    it('should validate its weights');

Mocha testrunner with pending specs

Seeing the tasks come up with little blue dots in the test-runner output, and then change to red and then green as I implemented first the test code and then the implementing code in the library was a pretty satisfying process, and I can definitely see its appeal. This is a whole aspect of BDD I’ll probably miss out on in this comparison, since I’m not planning on reimplementing the library itself over and over again. In recognition of this, though, I’m hoping to think up some features and hold them in abeyance so I can try more specification-first type development.

At this point I have a decent feel for Chai, and I will move on to the next framework; I’m thinking I’ll try out BusterJS, since from a cursory examination of Jasmine it looks to be very similar to Chai. Another thing which is bubbling up towards the top of my priority list is trying out the coveraje library, which measures test coverage for javascript unit tests. However, as a node.js only project, this will require me to figure out how to get the same test suite and module system running on the command-line and the browser, and I’d just as soon keep my focus on the browser for the moment.

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1 Comment

  1. BusterJS vs Chai/Mocha « Tim Gilbert's Blog

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