Unit testing AngularJS factories that have dependencies

Question

When unit testing an Angular factory (with Karma + Jasmine), how do I inject a stub dependency into the factory under test?

Here's my factory:

mod = angular.module('myFactoryMod', []);  mod.factory('myFactory', [   '$log', 'oneOfMyOtherServices', function($log, svc) {     return makeSomethingThatDoesSomethingWithTheseDependencies($log, svc);   } ]); 

oneOfMyOtherServices is needed when instantiating my factory.

Here's my test:

it('can get an instance of my factory', function() {   var oneOfMyOtherServicesStub;    angular.mock.module('myFactoryMod');    oneOfMyOtherServicesStub = {     someVariable: 1   };    //****How do I get my stub in my target? ****    angular.mock.inject(['myFactory', function(target) {        expect(target).toBeDefined();      }   ]); }) 

N.B. I know that $controller allows this for controllers, but I don't see an equivalent for factories.

Answer 1

There are two ways to accomplish something like this that I know of:

1. Use $provide and an anonymous module to inject the mock.
2. Inject the service you would like to mock and use jasmine's spying ability to provide mock values.

The second option only works if you know exactly which methods your code under test will be calling on the injected service and you can easily mock them out. As you seem to be accessing a data property on the service (rather than a method) pursuing the first option might be best.

Using $provide would roughly look like this:

describe('myFactory', function () {   // Load your module.   beforeEach(module('myFactoryMod'));    // Setup the mock service in an anonymous module.   beforeEach(module(function ($provide) {     $provide.value('oneOfMyOtherServicesStub', {         someVariable: 1     });   }));    it('can get an instance of my factory', inject(function(myFactory) {     expect(myFactory).toBeDefined();   })); }); 

Answer 2

The comment by @bentsai is actually very helpful for testing services; for completeness I am adding an example.

Here is a test for jasmine which does approximately what you're looking for. Note: this requires you to have angular-mocks included (this is what provides functions like module and inject).

describe('app: myApp', function() {   beforeEach(module('myApp'));   var $controller;   beforeEach(inject(function(_$controller_) {     $controller = _$controller_;   }));   // Factory of interest is called MyFactory   describe('factory: MyFactory', function() {     var factory = null;     beforeEach(inject(function(MyFactory) {       factory = MyFactory;     }))     it('Should define methods', function() {       expect(factory.beAwesome).toBeDefined()       expect(factory.beAwesome).toEqual(jasmine.any(Function))     });   }); }); 

This is a stub for what the module and associated factory definition could look like:

var app = angular.module('myApp', []); app.factory('MyFactory', function() {   var factory = {};   factory.beAwesome = function() {     return 'Awesome!';   }   return factory; }); 

In this case, it is clear the use of inject() allows you to pull in dependencies, just as you would expect in your normal angular application - and as such you can build up requirements to support testing things which rely on them.