Angular Project Blackjack: 3 – Unit Testing

(This post is part of my “from scratch” AngularJS project. If you are feeling lost, the first post is here.)

Now that we have our application running and our first controller done, the next thing we want to get setup is our testing framework. Having a testing framework ready to go is always beneficial, no matter what kind of development style you choose. I haven’t been able to get on board with TDD, but that is just my personal preference. I do like to have unit tests that cover my code, but I find it easier to write the tests after the code rather than before.

We are going to use the karma test runner suite to run our jasmine tests. Karma is a tool developed by the AngularJS team to run unit tests against a browser. It has the option to watch files for changes and re-run tests as soon as it detects them. It also reports passes/failures of the tests. Jasmine is the tool that we will write our tests in. We will test each part of the code, expecting certain things to happen, causing the tests to pass or fail.

Let’s get our environment setup to do some testing. Since this is first time we’ll be using npm to install something we want to save to the project, let’s first create a package.json file in the projects root directory:

{
  "name": "angular-blackjack",
 "version": "0.0.1"
}

Now we are able to install packages with npm and save them to our package.json file so that they can be installed on any other machine that we take the project to.

npm install karma --save-dev
npm install karma-phantomjs-launcher --save-dev
npm install jasmine-core --save-dev
npm install karma-jasmine --save-dev
bower install angular-mocks --save-dev
karma init karma.config.js

This will initialize our karma test runner file karma.config.js. When it asks for which browser you would like to test on, enter ‘PhantomJS’. This is our “headless” browser that runs nicely on the command line. The most important part right now is to make sure karma is loading all of our source files properly like so:

files: [
'./src/bower_components/angular/angular.min.js',
'./src/bower_components/angular-mocks/angular-mocks.js',
'./src/app/blackjack.module.js',
'./src/app/**/*.module.js',
'./src/app/**/*.js',
//Test Specs
'./src/app/**/*.spec.js'
] 

We are telling karma to load all of our javascript files in the src directory, but we want to specifically tell it to load the ‘.spec.js’ files. These will be our tests.

In order to execute tests, inject angular code and core services, we also install angular-mocks. From the documentation, angular-mocks (or ngMocks) “provides support to inject and mock Angular services into unit tests”. This means we do things like “inject”, “dump”, and “module”. Things that are necessary to test our code.

Following the style guide, we want to keep our tests along side of our source code and name the tests as close to the files they are testing as possible. Our first tests will be on our game.controller.js file, so we will put it in the same directory and call it game.controller.spec.js. Let’s go through our test:

describe('GameController Unit Tests', function () {
    var gameController;
    beforeEach(function () {
        module('blackjack.game');
        inject(function ($controller) {
            gameController = $controller('GameController');
        });
    });

    it('should be true', function () {
       expect(true).toBe(true);
    });

    it('should have a start and end function', function () {
        expect(gameController.start).toBeDefined();
        expect(typeof gameController.start).toBe('function');
        expect(gameController.end).toBeDefined();
        expect(typeof gameController.end).toBe('function');
    });
});

First, our describe() function, well, describes the tests that are run in the second parameter. Everything within beforeEach() function will be executed, I hate to say this, before each test is run. Notice a pattern here? The Jasmine framework makes very readable code. Next, we’ll load our blackjack.game module with the module() function. The inject() function is where things get a bit different. Since we will be creating a controller to test, we will use the $controller service. We’ll create our ‘GameController’ within the inject function, so we have access to the $controller service we just injected. If we were to need the $controller service outside of the inject function, there is another method we could use, but that is (yet another) blog post!

Now that our gameController variable has been defined, we can run some actual tests on it. The first test:

expect(true).toBe(true);

is a good way to reveal any setup issues you may have. If the tests fail, you know you’ve done something wrong. For the next test, we will actually verify that our controller has the ‘start’ and ‘end’ functions available:

it('should have a start and end function', function () {
    expect(gameController.start).toBeDefined();
    expect(typeof gameController.start).toBe('function');
    expect(gameController.end).toBeDefined();
    expect(typeof gameController.end).toBe('function');
});

These ‘toBeDefined’ functions verify that, yes, these functions are defined on the controller. But, if there was a property called ‘start’, this would validate as true also. That is why we have the ‘typeof’ validation as well.

These tests can be run on the command line with

karma start karma.conf.js

We now have our unit testing framework setup and running a test against our first controller that we wrote. Not a bad start, especially without using any sort of generator or starter template!

One final note. I switched over to WebStorm a few months ago and I couldn’t be happier with the IDE. Coming from a Visual Studio and an XCode background, this IDE makes me feel like home. Here is WebStorm’s visualization of the tests we just wrote, pretty great right!?!

Screenshot 2015-02-11 22.23.42

Here’s the results of our work!

Up next: Making A Directive

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