Headless knockout viewmodel testing with mocha

Question

I am trying to do headless testing of my knockout viewmodels. I purposely avoid dealing with any ui constructs in my viewmodel and leave the wireup to the html page.

Th

Answer 1

Maybe this is because Knockout has changed (as the accepted answer is old), but today, I don't believe this is necessary (anymore). You can easily test a Knockout viewmodel. All I needed to do was set the global ko variable in my test:

global.ko = require('../../Website/Scripts/knockout-3.4.0.js');

After that, you can run your test as usual: instantiate your viewmodel, perform any operations on it and assert.

I've written a little more about it, but in essence, this works for me:

global.ko = require('../../Website/Scripts/knockout-3.4.0.js');

var MyViewModel = require('../../Website/Scripts/myViewModel.js').MyViewModel;

describe('MyViewModel', function() {
    var viewModel;

    beforeEach(function(){
        viewModel = new MyViewModel();
    });

    describe('...', function() {
        /* And so on */
    });
});