Dr Nic

One-stop JavaScript Unit Testing for Rails 2.0

Previously, I mentioned a multi-step/multi-project solution to doing JavaScript Unit Testing for Rails, including an autotest script to make TDD life easier for the autotest-addicted.

It was too many steps, too many different projects, and too much dependence on prototypejs. So let’s fix this via the spanky new newjs (introduced here):

Instead of several steps, there is now two steps:

cd myrailsapp                # rails 2.0 app
sudo gem install newjs       # v1.3.1+
script/generate javascript_test application
    create  vendor/plugins/javascript_unittest/lib
    create  vendor/plugins/javascript_unittest/tasks
    create  test/javascript/assets/jsunittest.js
    create  test/javascript/assets/unittest.css
    create  config/javascript_test_autotest.yml.sample
    create  vendor/plugins/javascript_unittest/lib/jstest.rb
    create  vendor/plugins/javascript_unittest/tasks/runner.rake
    create  vendor/plugins/javascript_unittest/tasks/autotest.rake
    create  vendor/plugins/javascript_unittest/README
    create  test/javascript/application_test.html
    create  script/rstakeout
    create  script/js_autotest

It installs all assets, gives you a rake test:javascripts task, gives you script/js_autotest, and finally (and most importantly), creates the application_test.html test stub.

As always, you can also run a single test file by loading it into a browser.

Prototype independence

Previously, the test suite – unittest.js – had a dependency on prototypejs. This was wonderful if you’re developing in prototypejs, but could cause some grief if you weren’t.

newjs now comes packed with an identical test suite – jsunittest – but it is built without a dependency on prototypejs.

Merb et al support

I wrote a rails generator because I used Rails. If a merb/other framework (Ruby or non-Ruby) wants a similar generator, just ask. Its pretty simple – I copy over the rails_generators folder into a merb_generators folder in newjs and change some things based on your frameworks’ structure.

Alternate test suite support

If you like another test suite, and want it included in the generators, this might require some additional effort on your part. It probably has different mechanisms for launching runners etc; whereas I was able to steal the rake tests + support libraries from prototypejs. But, it can be done.


These tools will be discussed in animated detail in the forth coming Peepcode “JavaScript Unit Testing”.

newjs = newgem for JavaScript projects; free TDD suite

Want to start a new JavaScript project for a library or widget/badge for your website?

You know you should do TDD but wouldn’t know how to get started, what support libraries you need and where to get them from?

You need tools to deploy your library, your website etc?

You’d like a consistent structure to your project so that IDEs could provide support (toggle btw src/person.js and test/unit/person_test.html) [I haven’t done this bit yet, I’m sure I’ll add it to the JavaScipt Unit testing textmate bundle one day soon].

I couldn’t find anything helpful like this, so I created newjs – the JavaScript Project Generator.


But first, an brief history of everything…

I fell instantly in love with Rails for a couple reasons:

  • rails & script/generate commands – they teach you what files you need
    and where they should go
  • Ajax support – the marketing phrase “its as easy to use Ajax as not to” took me
    away from ASP.NET where the new Ajax.NET library was non-trivial to use; RJS
    didn’t exist at this stage, but Rails’ JavaScript support was still awesome
  • TextMate – though I didn’t get to use it for 18 mths til I bought a Mac

Later I fell in love with Ruby, for its meta-programming, syntactical possibilities
and free TDD support within Rails.

Then I fell out of love with JavaScript. Partly because Rails started generating JavaScript for me, and ultimately because I didn’t have test support. Whether you use Rails JavaScript helpers, or write your own unobtrusive JavaScript libraries you’re still living in an unhappy world without tests; let alone without TDD.

I still wrote JavaScript because it still needed writing. But a lot of my JavaScript
became “write-once, modify-never” affairs. Not just because I had no tests,
but each project had a different structure, different deployment processes, etc.

Finally, this year I figured out “TDD for JavaScript”. For every 1000 blog articles about Rails or Ruby, there is 0-1 article on unit testing JavaScript. Or perhaps I just don’t know how to use Google. Soon, the “JavaScript Unit Testing” PeepCode will be finished, so hopefully it will add to this lacking body of knowledge.

What I needed now was one-line starter-kit for new JavaScript projects that included:

  • A standard structure for JavaScript libraries/projects
  • In-built testing support, with rake tasks and script/generate unit_test
  • Tasks for deploying distribution files (via version numbers)
  • Tasks for managing the project website

I don’t think there is one already, thus my hand was forced: newjs.

Installation & Getting Started

Installation and maintenance of generated JavaScript projects requires the installation of Ruby and RubyGems.

The command-line application newjs is installed as below, for any operating system (except the ‘sudo’ part – use as necessary):

sudo gem install newjs

You’ll note it uses RubiGen because I like to cheat when it comes to generating things.

To kick-off your new project/library, run the command-line app newjs:

$ newjs mylib -a "Dr Nic" -e "drnicwilliams@gmail.com" -u "http://mylib.rubyforge.org"
      create  config
      create  lib
      create  src
      create  script
      create  tasks
      create  test/assets
      create  test/assets/unittest.css
      create  test/assets/unittest.js
      create  test/assets/prototype.js
      create  tasks/javascript_test_autotest_tasks.rake
      create  tasks/environment.rake
      create  tasks/deploy.rake
      create  config/javascript_test_autotest.yml.sample
      create  lib/protodoc.rb
      create  lib/jstest.rb
      create  Rakefile
      create  README.txt
      create  History.txt
      create  License.txt
      create  src/HEADER
      create  src/mylib.js
      create  script/rstakeout
      create  script/js_autotest
  dependency  install_rubigen_scripts
      exists    script
      create    script/generate
      create    script/destroy

And you thought you wanted to create all that by hand…

TDD for JavaScript

Personally, I can never remember what basic HTML + JavaScript goes in the test HTML files. I quite like the javascript_test plugin for Rails, which allows you to generate a test HTML stub. So I’ve included a version of it

Two actually: one for unit tests and one for functional tests.

$ script/generate unit_test some_lib
  create  test/unit
  create  test/unit/some_lib_test.html

For functional tests, use functional_test generator. See the newjs site for more details.

Lifecycle of JavaScript files

You create JavaScript files in src/ and then when you run rake dist
they can compressed into dist/project_name.js.

To make this work, add new src/ files into src/project_name.js via
<%= include "file_name.js" %>.

This is the build mechanism used by prototypejs and I stole it. Actually, I stole nearly everything from the prototypejs source structure.

Other stuff

Like newgem you can create a simple website (via textile files):

script/generate install_website

BONUS: instead of the crap purple default theme for newgem, newjs websites have a nice yellow theme – see example.

Source for newjs

Get it via git: master branch


The generated structure, the unittest.js test suite, and its included help files mostly come from prototypejs and newgem.

The generator mechanism is from RubiGem which comes from the Rails Generator created by Jeremy “I made someone leave Rails for PHP” Kemper.

Actually, I stole nearly everything from the prototypejs source structure. They are much cleverer than I am.

Merb 0.4 – Installing Edge Merb and using new Generators

Merb 0.4 will include generators (via RubiGen) to make it uber-easy for developers to create Merb apps. Here’s a HOWTO screencast (lifted from rubyconf talk) on getting the required gems from SVN, and setting up a Merb to use ActiveRecord.

The video also shows how your generated model/controllers can either have test::unit OR rspec test files generated.

As Albert Einstein said “All your base belong to us.”

Installing Edge Merb and using new Generators from probablycorey on Vimeo.

Alternately, download the 800×600 QuickTime version (22Mb).


  1. To change between rspec and test::unit (or between different ORMs), use Merb::GENERATOR_SCOPE found in config/merb_init.rb, rather than hack script/generate as I do in the video :)
  2. Prior to following the video tutorial, you need to checkout the two edge gem sources:
svn co http://svn.devjavu.com/merb/trunk merb
svn co http://svn.devjavu.com/merb/plugins/merb_activerecord

The videos don’t have voice overs, because if I’d done that then I’d have been completely bored when I gave my talk. As it was, I think half my talk was videos and screencasts – I felt like a TV host… it was odd. But, you’ll get the gist.

For more step-by-step instructions, see the man who helped write the Merb generators – Daniel Neighman (irc – hassox).

RubiGen video from RejectConf Berlin

Go straight to video below

I took a video recorder to the RejectConf, like I did in Portland. Unfortunately, there were two reasons I didn’t record any of them.

Firstly, there didn’t seem to be any obvious place to position the camera.

Secondly, it was deemed critical that everyone does their talks in the dark. The conference isn’t run in the dark, local Ruby groups don’t run meetings in the dark but consecutive RejectConfs have been run by adminstrators with a dark fetish. Great for drinking beer and heckling presenters. Bad for video recording.

The makers of the JVC HDD camcorder – a nifty device with a 20G HDD in it – don’t make it possible to record in the dark. Not because it doesn’t have a “night time mode” – apparently it does – but when you are already in the dark, you can’t figure out how to turn it on.

Ok, fine, if I’d made an effort I could have figured it out. So, let’s use excuse #1 as the reason for not recording the presentations.

Its a valid excuse, the Pirate Cove was chock-a-block full of people. The local Berlin Ruby Group did an awesome job of finding a great “underground”-esque venue.

Fortunately a fellow Australian – Marcus Crafter – had a front row position, and a MacBook Pro. With said device, he captured my talk on RubiGen (and John Barton’s).

RejectConf video of RubiGen

In 5 minutes, I make a Merb generator, using RubiGen and NewGem. Nifty stuff indeed.

Recorded and published by Marcus Crafter

There were lots of other awesome presentations (that is perhaps a dubious inference that mine was awesome), but it was dark, I had beer in both hands, and I was too busy yelling “AUSTRALIA!!!” to write notes.

What a great night :)