How do you mock a service in AngularJS when unit testing with jasmine?

Let's say I have a service shop that depends on two stateful services schedule and warehouse. How do I inject different versions of schedule and warehose into shop for unit testing?

Here's my service:

angular.module('myModule').service('shop', function(schedule, warehouse) {
    return {
        canSellSweets : function(numRequiredSweets){
             return schedule.isShopOpen()
                 && (warehouse.numAvailableSweets() > numRequiredSweets);
        }
    }
});

Here are my mocks:

var mockSchedule = {
    isShopOpen : function() {return true}
}
var mockWarehouse = {
    numAvailableSweets: function(){return 10};
}

Here are my tests:

expect(shop.canSellSweets(5)).toBe(true);
expect(shop.canSellSweets(20)).toBe(false);

beforeEach(function () {
  module(function ($provide) {
    $provide.value('schedule', mockSchedule);
  });
});

Module is a function provided by the angular-mocks module. If you pass in a string argument a module with the corresponding name is loaded and all providers, controllers, services, etc are available for the spec. Generally they are loaded using the inject function. If you pass in a callback function it will be invoked using Angular's $injector service. This service then looks at the arguments passed to the callback function and tries to infer what dependencies should be passed into the callback.

Improving upon Atilla's answer and in direct answer to KevSheedy's comment, in the context of module('myApplicationModule') you would do the following:

beforeEach(module('myApplicationModule', function ($provide) {
  $provide.value('schedule', mockSchedule);
}));

With CoffeeScript I run in some issues so I use null at the end:

beforeEach ->
  module ($provide) ->
    $provide.value 'someService',
      mockyStuff:
        value : 'AWESOME'
    null

You can look here for more info

https://docs.angularjs.org/guide/services#unit-testing

You want to utilize the $provide service. In your case

$provide.value('schedule', mockSchedule);

As you are using jasmine, there is an alternative way to mock the calls with jasmine's spies (https://jasmine.github.io/2.0/introduction.html#section-Spies).

Using these you can be targeted with your function calls, and allow call throughs to the original object if required. It avoids clogging up the top of your test file with $provide and mock implementations.

In the beforeEach of your test I would have something like:

var mySchedule, myWarehouse;

beforeEach(inject(function(schedule, warehouse) {

  mySchedule = schedule;
  myWarehouse = warehouse;

  spyOn(mySchedule, 'isShopOpen').and.callFake(function() {
    return true;
  });

  spyOn(myWarehouse, 'numAvailableSweets').and.callFake(function() {
    return 10;
  });

}));

and this should work in similar fashion to the $provide mechanism, noting you have to provide local instances of the injected variables to spy on.

I recently released ngImprovedTesting module that should make mock testing in AngularJS way easier.

In your example you would only have to replace in your Jasmine test the ...

beforeEach(module('myModule'));

... with ...

beforeEach(ModuleBuilder.forModule('myModule').serviceWithMocks('shop').build());

For more information about ngImprovedTesting check out its introductory blog post: http://blog.jdriven.com/2014/07/ng-improved-testing-mock-testing-for-angularjs-made-easy/

It is simpler to put the mock on the module like this:

    beforeEach(function () {
    module('myApp');
    module({
      schedule: mockSchedule,
      warehouse: mockWarehouse
     }
    });
  });

you can use injection to get reference to these mocks for pre test manipulations :

var mockSchedule;
var mockWarehouse;
        
beforeEach(inject(function (_schedule_, _warehouse_) {
     mockSchedule = _schedule_;
     mockWarehouse = _warehouse_;
}));

I hope my answer is not that useless, but you can mock services by $provide.service

beforeEach(() => {
    angular.mock.module(
      'yourModule',
      ($provide) => {
        $provide.service('yourService', function() {
          return something;
        });
      }
    );
  });