How do I mock $window injected manually in provider private function?

Question

I have the following provider:

angular.module('MyApp').provider('MyDevice', function () {

    var ngInjector = angular.injector(['ng']),
        $window = ngInjector.get('$window');

    function isMobileDevice () {
        return (/iPhone|iPod|iPad|Silk|Android|BlackBerry|Opera Mini|IEMobile/)
            .test($window.navigator.userAgent || $window.navigator.vendor || $window.opera);
    }

    this.$get = function () {
        return {
            isDesktop: function () {
                return !isMobileDevice();
            },
            isMobile: function () {
                return isMobileDevice();  
            }
        };
    };

});

And the following test spec:

describe('MyDeviceProvider', function () {

    var myDevice;

    beforeEach(function () {
        inject(['MyDevice', function (_myDevice_) {
            myDevice = _myDevice_;
        }]);
    });

    it('Test #1', function () {
        // Mock '$window.navigator.userAgent' to "desktop"
        expect(myDevice.isDesktop()).toEqual(true);
        expect(myDevice.isMobile()).toEqual(false);
    });

    it('Test #2', function () {
        // Mock '$window.navigator.userAgent' to "mobile"
        expect(myDevice.isDesktop()).toEqual(false);
        expect(myDevice.isMobile()).toEqual(true);
    });

});

My question is, how do I mock $window in both Test #1 and Test #2 so they are successful? I have tried with $provide.value and spyOn for countless objects, but I can't seem to mock the value of $window.navigator.userAgent to run my tests.

How do I solve this?

P.S: The code above acts only as a demonstration of my issue and I cannot change the provider into a service because of special requirements of the application.

Answer 1

Very crudely, you could do the following:

describe('MyDeviceProvider', function () {

    var myDevice,
        $window,
        navigator;

    beforeEach(function () {
        inject(['MyDevice', '$window', function (_myDevice_, _$window_) {
            myDevice = _myDevice_;
            $window = _$window_;
        }]);

        // Save the original navigator object
        navigator = $window.navigator;
    });

    afterEach(function () {
        $window.navigator = navigator;
    });

    it('Test #1', function () {
        // Mock the entire navigator object to "desktop"
        $window.navigator = {
            userAgent: "desktop" // Use a real "desktop" user agent
        };

        // Mock '$window.navigator.userAgent' to "desktop"
        expect(myDevice.isDesktop()).toEqual(true);
        expect(myDevice.isMobile()).toEqual(false);
    });

    it('Test #2', function () {
        // Mock the entire navigator object to "desktop"
        $window.navigator = {
            userAgent: "mobile" // Use a real "mobile" user agent
        };
        // Mock '$window.navigator.userAgent' to "mobile"
        expect(myDevice.isDesktop()).toEqual(false);
        expect(myDevice.isMobile()).toEqual(true);
    });

});

You should test different mocks mimicking different browsers too.