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.

Noah Freitas · Accepted Answer · 2013-05-15T14:53:58.633

94

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

Use $provide and an anonymous module to inject the mock.
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();
  }));
});

edited May 15 '13 at 14:53

answered May 15 '13 at 14:30

Noah Freitas

17,240
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Yeah I think choice 1 is the way to go. Thanks! – Roy Truelove May 17 '13 at 14:46
7

I'd like to inject the myFactory into all tests. Can it be done in a beforeEach? I tried but it didn't work... – Bennett McElwee Sep 20 '13 at 05:12
10

Thanks for this answer +1. It would be nice to add a code example also for option #2, for completeness. – klode Dec 10 '13 at 13:02
2

@BennettMcElwee Yes, you can. Like this: `var theFactory; beforeEach(inject(function(myFactory) { theFactory = myFactory; } )));` Then use `theFactory` in your test. – bentsai Sep 25 '14 at 14:44
@BennettMcElwee You can also go by the convention and use underscores to reduce the number of variables var theFactory; beforeEach(inject(function(_myFactory_) { myFactory = _myFactory_; } ))); – Stephane Apr 13 '15 at 16:57
Correct me if I'm wrong, I understand both options inject the actual service, with the option 1 stubbing one of its method ? Can't we inject a complete mocked service defined in another file ? – Stephane Apr 13 '15 at 17:02
what If i need a combination between mocking one service and injecting a real one? – Ricbermo Nov 12 '15 at 16:41
How would I spy on a method of this `oneOfMyOtherServicesStub`? – chovy Apr 12 '16 at 20:58
1

How can I test this factory method getItemList using Jasmine and karma. I am getting error: [$injector:unpr] http://errors.angularjs (function() { angular.module('riskCanvasApp').factory('itemsService', itemsService); itemsService.$inject = [ '$http', '$q','$compile', 'UrlService', 'accountDetailsMainService', 'sharedService', 'authenticationSvc' ]; function itemsService($http, $q, $compile, urlService, accountDetailsMainService, sharedService, authenticationSvc) { – AMRESH PANDEY Apr 17 '17 at 07:18

score 12 · Answer 2 · answered Nov 26 '14 at 07:53

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.

You have missed the part where you inject a stub dependency to MyFactory in testing. — skolsuper, Jan 28 '16 at 09:12

Unit testing AngularJS factories that have dependencies

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