Testing with sinon, QUnit and jquery. function loads on $(document).ready(function(){})(jQuery)

I have a function inside my javascript file as follow:

    `(function($){
    "use strict";
    $(document).ready(loadPics);

    function loadPics(){
        $.getJSON(formUrl(), function(data){
             if (data) {
                createDomElm(data);
            }
        });
    }
    })(jQuery);

the test from my spec.js look as follow:

QUnit.test("jQuery.getJSON should be called", function (assert) {
    var spy = this.spy(jQuery, 'getJSON');

    assert.ok(callCount('getJSON'));
    sinon.assert.callCount(spy, 1);
});`

the function loadPics() containing the getJSON inside of my jQuery gets called. but when i try to get the callcount(spy, 1) it returns false; The only thing i am trying to test is how many getJSON calls are inside my JS, without making the functions available to my window object.