Why do I see “define not defined” when running a Mocha test with RequireJS?

Question

I am trying to understand how to develop stand-alone Javascript code. I want to write Javscript code with tests and modules, running from the command line. So I have insta

Answer 1

You are trying to run JS modules designed for browsers (AMD), but in the backend it might not work (as modules are loaded the commonjs way). Because of this, you will face two issues:

1. define is not defined
2. 0 tests run

In the browserdefine will be defined. It will be set when you require something with requirejs. But nodejs loads modules the commonjs way. define in this case is not defined. But it will be defined when we require with requirejs!

This means that now we are requiring code asynchronously, and it brings the second problem, a problem with async execution. https://github.com/mochajs/mocha/issues/362

Here is a full working example. Look that I had to configure requirejs (amd) to load the modules, we are not using require (node/commonjs) to load our modules.

> cat $PROJECT_HOME/test/test.js

var requirejs = require('requirejs');
var path = require('path')
var project_directory = path.resolve(__dirname, '..')

requirejs.config({
  nodeRequire: require, 
  paths: {
    'widget': project_directory + '/src/js/some/widget'
  }
});

describe("Mocha needs one test in order to wait on requirejs tests", function() {
  it('should wait for other tests', function(){
    require('assert').ok(true);
  });
});


requirejs(['widget/viewModel', 'assert'], function(model, assert){

  describe('MyViewModel', function() {
    it("should be 4 when 2", function () {
        assert.equal(model.square(2),4)
    })
  });

})

And for the module that you want to test:

> cat $PROJECT_HOME/src/js/some/widget/viewModel.js

define(["knockout"], function (ko) {

    function VideModel() {
        var self = this;

        self.square = function(n){
            return n*n;
        }

    }

    return new VideModel();
})