Unit Test for a scope that retrieves an integer (osVersion)

I am trying to write a unit test for a $scope that retrieves the customer's osVersion in a file called module.js.

Here is the function:

angular.module('app.customer-view', [])

.controller('customer-view.mainController', [
    '$scope',
    '$window',
    '$document',
    'customerViewService',
    'app',
    'customerViewConstants',

    function ($scope, $window, $document, customerViewService, app, customerViewConstants) {
        'use strict';

        function getOSVersion() {
            if (window.nativeBridge) {
                return window.nativeBridge.deviceProfile.getOSVersion();
            }
        }
    }

    function init() {

        $scope.osVersion = getOSVersion();
    }

    init();
]};

How to write a unit test that checks to see that $scope.osVersion return a version number as it should? This is what I have so far:

describe('customer-view.mainController', function () {
    'use strict';

        /* Variables directly derived from module.js */

    var scope, 
        _window,
        spec_customerService,
        createController,
        app,       
        customerViewConstants,

        /* Extra dependencies required for unit test cases */ 

        rootScope,
        $controller,
        stub,
        deferredObj;

    beforeEach(function(){
        module('app.customer-view', 'senses');

        stub = {
            data: {
                'osVersion': 4.02
            }
        };

        inject(function($injector) {
            $controller = $injector.get('$controller');
            rootScope = $injector.get('$rootScope');    
            customerViewConstants = $injector.get('customerViewConstants');
            spec_customerService = $injector.get('customerViewService');
            deferredObj = $injector.get('$q');

            app = {
                setRadialHeaderData:function(){
            }
        };

        _window = {
            document: {
                createEvent: function(){
                    return {initUIEvent : function(){}};
                }
            },
            dispatchEvent: function(){}
        };

        createController = function() {
            scope = rootScope.$new();
            return $controller('customer-view.mainController', {
                '$scope': scope,
                '$window': _window,
                '$document': _window.document,
                'app': app
            });
        };
    });
});

    it('should get the OS version when native is present', function(){
        spyOn(scope, 'osVersion');
        createController();
        scope.$apply();
        expect(scope.osVersion).toEqual(stub.data.osVersion);
    });

});

This test above is now returning: Error: osVersion() method does not exist in C:/xampp/htdocs/myProject/customer-view/senses/node_modules/jasmine-core/lib/jasmine-core/jasmine.js