Dead simple JavaScript Unit Testing in Rails

Formats: Video/Screencast (410 Mb, torrent) | Video only (vimeo)

Writing tests are great for helping you design and think out your code, and the bonus is you end up with a test suite to aide in fighting against regressions. Why? It’s embarrassing when your JavaScript doesn’t work in production.

But how do you get started with testing JavaScript? How do you make it easy? I mean, so easy that you’d feel stupid to not write tests?

And how do you know if your designer/HTML-chopper has broken your JavaScript? How do you find out if JavaScript is broken in CI builds? And what is the appropriate punishment for designers who break JavaScript?

Finally, it is now uber easy to get started: the blue-ridge plugin for Rails. (I previously discussed it near the bottom)

To spread the word, I travelled to London, England for the Rails Underground conference a few months ago. The presentation is now online (recorded and published by SkillsMatter).

I was also recording the screen during the presentation and we’ve composited the two together (a la confreaks) and it’s available via BitTorrent. If you can seed for the next few days, that would be greatly appreciated too.

The talk is 45 minutes and questions are 6 mins. (I sadly don’t repeat into the microphone some of the questions because the room acoustics were good and everyone could hear everyone else’s questions. Sorry.)

Go get it now.

Why Blue Ridge?

This recording was done in July 2009, a few months ago. Is Blue Ridge still the bees-knees? I think so. It has issues, edge cases and bugs, but I don’t think there is a similar nor better Rails extension that includes (out of the box) a headless test runner, a bundle of test libraries (Screw.Unit, Smoke, etc), Rails generators, and automated discovery of “the designer broke our JavaScript!” lynch-mobbing (see my branch below).

These are the things I want. If there’s a better testing environment (say on HTMLUnit instead of env.js), then I think the killer packaging is to bundle it all up, with the features above, so it is drop-in, dead simple to use.

My history with JavaScript testing

In the introduction I talk about my life with JavaScript and testing. Here is the extended summary if it’s interesting to you at all:

• 2005:
  • ASP.NET + Ajax == “crapola”
  • Rails promo: “easier to do Ajax than not to”
  • Inline JavaScript helpers
• 2006:
  • RJS to generate JavaScript
• 2007:
  • JavaScript only in its own files
  • Unobtrusive JavaScript
  • Got myself into terrible mess with MyConfPlan
  • How to test JavaScript?
• 2008:
  • Figured out how to test it
  • Write a PeepCode but never published it
  • Wrote newjs and jsunittest
• 2009:
  • Found BlueRidge plugin for Rails
  • Headless test runner
  • BDD tests via Screw.Unit
  • Generators

Miscellaneous

I mention a couple of miscellaneous things. Here’s a summary.

My fork of blue-ridge has the feature to render sample HTML from your templates. It wasn’t accepted into the primary blue-ridge library because it was rspec only. Perhaps someone can make it work for test/unit etc.

I alias the script/generate command:

alias gen="script/generate"

I’m extending TextMate with Ciarán Walsh’s ProjectPlus plug-in (source). It’s sweet.

Thanks

Thanks to Mark Coleman for organising Rails Underground, inviting me over, and having the sessions recorded. And to SkillsMatter for recording and publishing the raw footage.

Thanks to Bo Jeanes for helping to get Final Cut Pro to mash the screencast and the SkillsMatter video into one video.

Thanks to Jack Chen for hacking some code to push the video up to s3 (when Transmit and BaconDrop were failing me)

Related posts:

1. Using CoffeeScript in Rails and even on Heroku I’m pretty excited about CoffeeScript as a clean-syntax replacement for...
2. First look at rails 3.0.pre This article is out of date in some aspects....
3. Rails themes can remember things I was getting annoyed at having to remember all the...