Test promise chain angular

How do you mock the second call to then in this code in an angular service.

 myService.promise.then(function () {
            userConfig = userService.getUserConfiguration();
        }).then(function () {
         //do more stuff
        })

I know that I can mock the first call as follows:

beforeEach(inject(function ($q) {
    var deferred = $q.defer();
    spyOn(myService.promise, 'then').and.returnValue({$promise: deferred.promise});
    deferred.resolve();
}));