Unit-testing slider directive with AngularJS + Jasmine

I am a newbie to both Angularjs and unit-testing with jasmine, so iI hope this makes sense and is correct enough to get an answer :) I am trying to test an angularJS directive that creates sliders taken from bootstrap-slider .

This is my directive (the slider calls a function on sliding based on slider-fn attribute) :

angular.module('testAngular').directive('sliderDir',function($parse){

    return {
        link :function(scope,element,attrs){
        element.slider({value: parseInt(attrs.value),
            min: parseInt(attrs.min),
            max: parseInt(attrs.max),
            step: parseInt(attrs.step)
        });
        element.on("slide",function(event, ui){
            scope.$apply(function() {
                var invoker = $parse(attrs.sliderfn);
                invoker(scope, {arg1: element.val() });
            });
        });
    }
    }
})

This is my unit test, where I am trying to recreate a slider and test his values. (Next, I should test if the correct function is being called) :

...

describe("testing sliderDir", function(){

    beforeEach(angular.mock.module("testAngular"));
    var element;
    var $scope;


    beforeEach(angular.mock.inject(function($compile,$rootScope){

        $scope = $rootScope;
        element = angular.element('<input id="ex1" slider-dir="" sliderFn="slideFunction(arg1)" type="text" min="2750" max="30000" step="250" value="13000"/>');
        $compile(element)($rootScope);


    }))

    it("has correct values", function(){
        $scope.$digest();

        expect(element.find('input').slider("getAtribute","value")).toEqual(13000);
        expect(element[0].slider("getAttribute","min")).toEqual(2750);

    })
})

Neither the first or the second expect works as expected : I have added three logs :

console.log(element.find('input').length);  //this one logs 0 instead of 1 as i would expect
console.log(element);   //this is an array of length 1 
console.log(element[0]); //this is my input element with added class="ng-scope"

How can I call a function like slider() while testing? Why does find() return 0 as length?

Thank you in advance!