将服务注入Angular单元测试时出现Unknown Provider错误

Question

I'm fairly new to Angular and have reviewed all the similarly related questions on Stack Overflow but none have helped me. I believe I have everything set up correctly but am still getting an 'Unknown Provider' error when attempting to inject a service into a unit test. I have laid out my code below - hopefully someone can spot an obvious error!

I define my modules in a seperate .js file like this:

angular.module('dashboard.services', []);
angular.module('dashboard.controllers', []);

Here is where I define a service called EventingService (with logic removed for brevity):

angular.module('dashboard.services').factory('EventingService', [function () {
    //Service logic here
}]);

Here is my controller that uses the EventingService (this all works fine at runtime):

angular.module('dashboard.controllers')
    .controller('Browse', ['$scope', 'EventingService', function ($scope, eventing) {
        //Controller logic here
}]);

Here is my unit test - its the line where I attempt to inject the EventingService that causes an error when I run the unit test:

describe('Browse Controller Tests.', function () {
    beforeEach(function () {
        module('dashboard.services');
        module('dashboard.controllers');
    });

    var controller, scope, eventingService;

    beforeEach(inject(function ($controller, $rootScope, EventingService) {
        scope = $rootScope.$new();
        eventingService = EventingService

        controller = $controller('Browse', {
            $scope: scope,
            eventing: eventingService
        });
    }));


    it('Expect True to be True', function () {
        expect(true).toBe(true);
    });
});

When I run the test I get this error:

Error: Unknown provider: EventingServiceProvider <- EventingService

I have ensured that my jasmine specrunner.html file has all the necessary source files (this is an Asp.Net MVC project):

<!-- Include source files here... -->
@Scripts.Render("~/bundles/jquery")
<script type="text/javascript" src="@Url.Content("~/Scripts/angular.js")"></script>  
<script type="text/javascript" src="@Url.Content("~/Scripts/angular-mocks.js")"></script>                 

<script type="text/javascript" src="@Url.Content("~/App/scripts/app.js")"></script>                       <!-- Angular modules defined in here -->
<script type="text/javascript" src="@Url.Content("~/App/scripts/services/eventing.js")"></script>         <!-- My Eventing service defined here -->


<script type="text/javascript" src="@Url.Content("~/App/scripts/controllers/browse.js")"></script>        <!-- My Browse controller defined here -->

<!-- Include spec files here... -->
<script type="text/javascript" src="@Url.Content("~/App/tests/browse.js")"></script>                      <!-- The actual unit test here -->

I just can not fathom why Angular is throwing this error complaining about my EventingService. My controller works fine at runtime - it's just when I try to test it that I am getting an error so I am curious as to whether I have screwed something up with the mocking/injection.

The Angular help on testing is rubbish so I am stumped at present - any help or suggestions anyone can give would be very appreciated. Thanks.

Answer 1

I just ran into this and solved it by switching to getting the service using the $injector explicitly:

var EventingService, $rootScope;
beforeEach(inject(function($injector) {
  EventingService = $injector.get('EventingService');
  $rootScope = $injector.get('$rootScope');
}));

I wish I could tell you why this works and why the simple

beforeEach(inject(function(EventingService) {   ....  }));

does not, but I don't have the time to investigate the internals. Always best to use one coding style and stick to it.

This style is better in that the name of the variable that you use in your tests is the correct name of the Service. But it is a bit verbose.

There is another angular magic feature that uses strange variable names like $rootScope but I don't like the hacky look of that.

Note that the most of the time people get this error because they didn't include the modules:

beforeEach(module('capsuling'));
beforeEach(module('capsuling.capsules.services'));

Answer 2

If your controllers (defined under dashboard.controllers module) depend on some services which are enclosed in different module ( dashboard.services ) than you need to reference the dependency modules in your module signature:

angular.module('dashboard.services', []);
angular.module('dashboard.controllers', ['dashboard.services']);

Answer 3

While this question is fairly old i lost significant time solving a problem similar to this one, ie:

Error: Unknown provider: SomeServiceProvider <- SomeService

Hence, i'm leaving here another possible cause to this issue. Hopefully, it would helpful to someone.

In my case, i had in my project two modules with the exactly same name but with different dependencies being created, ie, two different .js files with:

angular.module('moduleName', [dependencies]))

From angular documentation:

Passing one argument retrieves an existing angular.Module, whereas passing more than one argument creates a new angular.Module

Conclusion : It turns out that what was being injected in the test was the module with the wrong dependencies. Removing the second argument from the module that was erroneously being created solved the problem.

Answer 4

Have you tried defining an additional module that depends on your other aggregated modules like so:

angular.module( 'dashboard', [ 'dashboard.services', 'dashboard.controllers' ] )

So you can in the beforeEach specify the one module that has both submodules defined in it like so:

describe('Browse Controller Tests.', function () {
    beforeEach(function () {
        module('dashboard');
    });

    var controller, scope, eventingService;

    beforeEach(inject(function ($controller, $rootScope, EventingService) {
        scope = $rootScope.$new();
        eventingService = EventingService

        controller = $controller('Browse', {
            $scope: scope,
            eventing: eventingService
        });
    }));


    it('Expect True to be True', function () {
        expect(true).toBe(true);
    });
});