title	slug	createdAt	language	preview
Unit testing Angular.js app with node.js, mocha, angular-mocks and jsdom	unit-testing-angular-js-app-with-node	2015-07-05T18:04:33Z	en	Majority of search result about unit testing Angular.js apps is about how to do it by using test frameworks that run the tests in a real browser. Even though it's great to be able to test your code in multiple platforms, in my opinion it creates a lot of boilerplate code and makes it hard to run the tests in, for instance a CI-server.

Testing Angular.js app headlessly with node.js + mocha

Lean unit tests with minimal setup

Code examples

Keypoints

Fake DOM (Everything works without a real browser)
Uses ngMocks to inject and mock Angular.js dependencies
I'm assuming you are already using browserify (but everything works fine without it)

Some background

Majority of search result about unit testing Angular.js apps is about how to do it by using test frameworks that run the tests in a real browser. Even though it's great to be able to test your code in multiple platforms, in my opinion it creates a lot of boilerplate code and makes it hard to run the tests in, for instance a CI-server.

In most cases I just want to include a module from my code to my tests, call methods from the module and do assertions to assure that everything is working properly.

1. Set up a mock DOM

npm install jsdom@~3.x.x -D

Even though jsdom 4.0 is already available by the time I'm writing this we will still use the 3.x version because the most recent versions support only io.js.

tests/test-helper.js

var jsdom = require('jsdom').jsdom;

global.document = jsdom('<html><head><script></script></head><body></body></html>');
global.window = global.document.parentWindow;
global.navigator = window.navigator = {};
global.Node = window.Node;

2. Install and set-up ngMocks

If you have installed Angular with Bower:

bower install angular-mocks -D

If you have installed Angular with npm:

npm install angular-mocks -D

⚠️ Make sure your angular-mocks version matches your angular version

tests/test-helper.js

var jsdom = require('jsdom').jsdom;

global.document = jsdom('<html><head><script></script></head><body></body></html>');
global.window = global.document.parentWindow;
global.navigator = window.navigator = {};
global.Node = window.Node;

global.window.mocha = {};
global.window.beforeEach = beforeEach;
global.window.afterEach = afterEach;

/*
 * Only for Bower users
 */
require('../bower_components/angular');
require('../bower_components/angular-mocks');

/*
 * Only for NPM users
 */
require('angular/angular');
require('angular-mocks');

global.angular = window.angular;
global.inject = global.angular.mock.inject;
global.ngModule = global.angular.mock.module;

3. Install Mocha and write some tests

npm install mocha -D

I assume that your directory structure looks something similar to this

app/
  scripts/
    services/
      - userService.js
    controllers/
package.json

Lets create a new directory called _tests_ under our services/ directory and a new test file called userService.js there.

app/
  scripts/
    services/
      __tests__/
        - userService.js
      - userService.js
    controllers/
package.json

Here's a reference implementation of our userService.js

angular.module('myServices.user', []).service('UserService', function() {
  return {
    getUsers: function () {
      return [];
    }
});

app/scripts/services/_tests_/userService.js

var assert = require('assert');
require('../../../tests/test-helpers');

// Loads the module we want to test
require('../userService');

describe('User service', function() {
  beforeEach(ngModule('myServices.user'));
  
  it('should return a list of users', inject(function(UserService) {
    assert.equal(UserService.getUsers().length, 0);
  }));
});

Now by running ./node_modules/.bin/mocha app/scripts/**/__tests__/**/*.js we should see that our tests work.

Protip: You most likely want to add that to your package.json's scripts.test field.

"scripts": {
  "test": "mocha app/scripts/**/__tests__/**/*.js"
}

Notice how you don't have to use the ./node_modules... path anymore since npm resolves it for you. If you are using npm >=2.0 you can no also use npm test -- --watch to start Mocha in watch mode.

For Browserify users

If you want to also mock the modules your services (or what ever you are testing) are using I would recommend proxyquire.

Known issues

Broken `--watch` mode

If you've installed Angular.js with npm you'll notice that on Mocha's watch mode your fake DOM is recreated on every reload but the Angular.js code isn't re-evaluated which leads into thrown exceptions about angular being undefined. There's two causes for this: angular and angular-mocks are both singletons and Mocha doesn't re-evaluate anything in node_modules. This problem doesn't exist for Bower users since their angular and angular-mocks are in the bower_components directory.

Solution

Even though this is a bit dirty, I solved this by invalidating require cache for angular and related modules.

tests/test-helper.js

//...
delete require.cache[require.resolve('angular')];
delete require.cache[require.resolve('angular/angular')];
delete require.cache[require.resolve('angular-mocks')];

require('angular/angular');
require('angular-mocks');

global.angular = window.angular;
global.inject = global.angular.mock.inject;
global.ngModule = global.angular.mock.module;

@rikukissa thanks for sharing this!

I had problems with Mocha --watch ... The first run would work, but subsequent test runs would fail, most likely due to leaky dom. So I created my own watcher that runs Mocha in a child process so each run is clean:

// watch.js

if (process.argv.length < 3) {
    console.log('Usage: node watch.js [mocha arguments...]');
    return;
}

var spawn = require('child_process').spawn;
var chokidar = require('chokidar');
var args = process.argv.slice(2);

var onChange = function() {
    var mocha = spawn('./node_modules/mocha/bin/_mocha', args, {stdio: "inherit"});

    mocha.on('close', function(code) {
        console.log('watching...');
    });
};

var opts = {
    ignored: /(^|[\/\\])\../,
    persistent: true
};

// watch for changes
chokidar.watch('**/*.js', opts).on('change', onChange);

// don't wait for first change before running tests
onChange();

rikukissa/POST.md

Testing Angular.js app headlessly with node.js + mocha

Keypoints

Some background

1. Set up a mock DOM

2. Install and set-up ngMocks

3. Install Mocha and write some tests

For Browserify users

Known issues

Broken `--watch` mode

rikukissa commented Oct 19, 2016

PrestonII commented Dec 22, 2016

adamrbennett commented Mar 14, 2017

brandonros commented Jan 19, 2018

kindy commented Jan 22, 2018

lars-erik commented Jan 27, 2020

rikukissa/POST.md

Testing Angular.js app headlessly with node.js + mocha

Keypoints

Some background

1. Set up a mock DOM

2. Install and set-up ngMocks

3. Install Mocha and write some tests

For Browserify users

Known issues

Broken --watch mode

rikukissa commented Oct 19, 2016

PrestonII commented Dec 22, 2016

adamrbennett commented Mar 14, 2017

brandonros commented Jan 19, 2018

kindy commented Jan 22, 2018

lars-erik commented Jan 27, 2020

Broken `--watch` mode