Testing JavaScript Written for the Browser in Node JS

Question

I have some JavaScript that is going to run in the browser, but I have broken the logic based functions that have nothing to do with the DOM into their own js files.

If it's possible, I would prefer to test these files via command line, why have to open a browser just to test code logic? After digging through multiple testing libraries for Node.js. I suppose it's not a big deal, but that seems to require that I build a whole node project, which requires that I provide a main, which doesn't really exist in my project since it's just functions that get fired from a web page.

Is there a solution for testing JavaScript functions that can be as simple as just writing a .js file with tests in it and calling a utility to run those tests? Something more simple than having to set up a runner, or build a project and manage dependencies? Something that feels like writing and running JUnit Tests in Eclipse, and a little less like having to set up a Maven project just to run MVN test?

As a follow-up question, is this even the right way to go about it? Is it normal to be running tests for JavaScript that is meant to run in the browser in Node.js?

Answer 1

Use test runners like mocha or jasmine. Very easy to setup and start writing test code. In mocha for example, you can write simple test cases like

var assert = require('assert');
var helper = require('../src/scripts/modules/helper.js');
var model = require('../src/scripts/modules/model.js');

model.first.setMenuItem ({
  'title': 'Veggie Burger',
  'count': 257,
  'id': 1
});

describe('increment', function(){
  console.log ("Count : " + model.first.getMenuItem().count);

  it('should increment the menu item', function(){
    helper.increment();
    assert.equal(model.first.getMenuItem().count, 258);
  });

});

and run them like

$ ./node_modules/mocha/bin/mocha test/*.js

where test/*.js are the specifications file (unit test file like the one above)

the output will be something like:

Count : 257


  increment
    ✓ should increment the menu item


  1 passing (5ms)

You can even use headless browser like PhantomJS to test containing DOM manipulation code.