mock-service-example.js

// Mocked Service
angular.module('mock.users', []).
    factory('UserService', function($q) {
        var userService = {};

        userService.get = function() {
            return {
                id: 8888,
                name: "test user"
            }
        };

        // other stubbed methods
        
        return userService;
    });

// Controller Unit Tests
describe('My Controller', function() {
    var ctrl, scope;

    beforeEach(module('module.containing.controller'));
    
    // include previous module containing mocked service which will override actual service, because it's declared later
    beforeEach(module('mock.users')); 

    beforeEach(inject(function($controller, $rootScope, _UserService_) { // inject mocked service
        scope = $rootScope.$new();

        ctrl = $controller('MyController', {
            $scope: scope,
            UserService: _UserService_
        });

    }));
    
    // unit tests go here
    
  });