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This page shows how to configure a project that uses RequireJS. It is based on Jake's post.

Configure Testacular

Directory Setup

For clarity in the example configuration files and test below, the directory structure upon which these are based looks like this:

    jquery.js #etc
    chai/ #etc

Initialize Testacular

Testacular comes with a nice utility for generating a config file (default name: testacular.conf.js) that it needs in order to run.

In your terminal, type:

$ testacular init

This will give you a series of prompts for things such as paths to source and tests and which browsers to capture.

RequireJs Shim

Not immediately apparent is the fact that the ‘shim’ config from RequireJs 2.x does not work from within Testacular. I haven’t yet figured out why. For instance, I was constantly getting ‘Backbone’ is not defined messages even though it was specified in the ‘shim’ config and required in the test. I could have been doing something wrong. My solution thus far has been to list each of the non-RequireJs modules and their dependencies in the files attribute of testacular.conf.js.


The final point is that the RequireJs main module for your test runner should be the last file listed.

So, finally, here is the ‘file’ excerpt of testacular.conf.js:

files = [

  // libs required for test framework
  {pattern: 'node_modules/chai/chai.js', included: false},

  // put what used to be in your requirejs 'shim' config here,
  // these files will be included without requirejs

  // put all libs in requirejs 'paths' config here (included: false)
  {pattern: 'lib/**/*.js', included: false},

  // all src and test modules (included: false)
  {pattern: 'src/**/*', included: false},
  {pattern: 'test/**/*.test.js', included: false},

  // test main require module last

This config is awesome. It replaces an html test runner that you would otherwise have to build.

RequireJs Main Module

Just like any RequireJs project, you need a main module to bootstrap your tests. In the main module, you setup the require.config.

Testacular /base Directory

Testacular serves files under the /base directory. So, on the server, requests to files will be served up under http://localhost:9876/base/*. The RequireJs config for baseUrl gives a starting context for modules that load with relative paths. When setting this value for the Testacular server, it will need to start with /base. I want my baseUrl to be at the root of my /src directory so relative requires in the source won’t need to change. My baseUrl has the value of /base/src.

Require Each Test File

One of the things I hate is having to update a master list of all tests to run every time I add a test. There is no config option for this, but there's an easy way to get around it by filtering the tests from the window.__testacular__.files object. The code is included in the example below and the original suggestion came from https://github.com/testacular/testacular/pull/236.

Asynchronously Run Testacular

Because the RequireJs require statements are asynchronous, Testacular needs to wait until they’re done (the code is loaded and ready) before it starts the tests.

The main-test.js file ends up looking like this:

var tests = Object.keys(window.__testacular__.files).filter(function (file) {
  return /\.test\.js$/.test(file);

  // Testacular serves files from '/base'
  baseUrl: '/base/src',
  paths: {
    require: '../lib/require',
    text: '../lib/text'
  // ask requirejs to load these files (all our tests)
  deps: tests,
  // start test run, once requirejs is done
  callback: window.__testacular__.start

RequireJs Test in Testacular

All the setup thus far has been in preparation for the code to follow. The test can now be setup as a RequireJs module. It can require the source code under test. It can use Mocha (or whatever framework there is a Testacular adapter for).

I will also use Chai in order to get the ‘should’ BDD-style assertions. Note that by using RequireJs and running in the browser, we can’t just require('chai'). It has to be required using the asynchronous callback to avoid this error:

Uncaught Error: Module name “../node_modules/chai/chai” has not been loaded yet for context: _. Use require([])

And finally, should() must be invoked to be available in the test.

So, a simple test will look like:

define(['../node_modules/chai/chai', 'MyModule'], function(chai, MyModule) {

  var should = chai.should();

  describe('MyModule', function () {
    describe('#initialize()', function () {
      it('should be a stinkin object', function () {
        var yippee = new MyModule();

Run the Tests in Testacular

To start the Testacular server:

$ testacular start

If you didn't configure to watch all the files and run tests automatically on any change, you can trigger the tests manually. Just type:

$ testacular run