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Karl Matthias

Principal Systems Engineer at Nitro. Co-Author of "Docker: Up and Running" from O'Reilly Media. Dublin, Ireland.




CoffeeScript Testing on Travis CI

I have recently been working on Troll-opt, a powerful but simple command line parser for Node.js that was inspired by William Morgan’s Trollop gem for Ruby.  I wanted to get CI running and Travis CI is a free for open source service that makes continuous integration fairly painless.  It wasn’t obvious how to get it running with CoffeeScript, though, so here is what I learned.

I had already set up a Cakefile that builds and runs the tests on my project.  I’m testing with Pivotal’s Jasmine, which is a lot like RSpec and thus very familiar to me, and a darn nice tool.  In combination with jasmine-node, it works great from the command line, too.

The Cakefile looks like this:

{spawn} = require 'child_process'
{print} = require 'util'
fs      = require 'fs'

spawnAndRun = (command, args, callback) ->
  subproc = spawn(command, args)
  subproc.stderr.on 'data', (data) ->
  process.stderr.write data.toString()
  subproc.stdout.on 'data', (data) ->
  print data.toString()
  subproc.on 'exit', (code) ->
  callback?() if code is 0

test = (callback) ->
  spawnAndRun 'jasmine-node', ['--coffee', 'spec'], callback

build = (callback) ->
  fs.mkdir 'lib', 0o0755
  print "compiling..."
  spawnAndRun 'coffee', ['--compile', '--output', 'lib', 'src'], callback
  print "\n"

task 'test', 'Run all tests', ->

task 'build', 'Build the Javascript output', ->

There’s no rocket science there, then.  It just creates a build and a test task that make it easy to invoke from Travis CI.  You could alternatively do this with a custom script, or with commands directly inserted in the Travis CI configuration (see below).  So, on to the actual integration.

First, you need your package.json file to contain some things it might not otherwise.  You need all the things you should have normally, including devDependencies to make sure this module can be built and tested.  But then, I added a scripts section which tells npm and also Travis CI, what to to do test and install this:

"devDependencies": { 
    "jasmine-node": ">=1.0.26", 
    "coffee-script": "latest" },
"scripts": {
  "test": "./node_modules/.bin/cake test",
  "install": "./node_modules/.bin/cake build"

The devDependencies guarantee that CoffeeScript and Jasmine are installed. The install script ensures that our code has been compiled to Javascript and put into the lib directory.

Note the paths. These assume that you are installing your npm packages locally, hence the ./node_modules/.bin path which is where npm puts binaries from installed packages.  The “test” command will be invoked by npm when you run npm test. This ensures that Travis knows how to test your application.

Travis CI uses a YAML file to configure it, called .travis.yml.  We need to tell Travis that we are using Node.js so that it doesn’t try to build a Ruby project.  Then, we need to tell it which commands to run.  In this case, we are going to install the coffee-script package locally to make sure that cake is in the right path.  The before_script definition will call a script before any tests are run.  before_install, will likewise run before the normal npm install is called on the dependencies in the package.json.

language: node_js
  - 0.8
  - 0.6
  ./node_modules/.bin/cake build
  - npm install coffee-script

Be sure to login to Travis and set up your GitHub account and authorize the commit hook from GitHub to trigger it. This is a few simple steps. Now, when you push to GitHub, your CoffeeScript should get compiled, and your tests should get run. Status will be reported on Travis, or optionally via an image you link into your README.md on GitHub.

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