stest/public/Plugin/cropper/cropper_files/test/methods/zoom.js

$(function () {

  'use strict';

  var $image = $(window.createCropperImage());

  $image.cropper({
    built: function () {
      var cropper = $image.data('cropper'),
          image = cropper.image;

      QUnit.test('methods.zoom', function (assert) {
        var width = image.width,
            height = image.height;

        $image.cropper('zoom', 0.1);

        assert.ok(image.width > width);
        assert.ok(image.height > height);
        assert.notEqual(image.width, width);
        assert.notEqual(image.height, height);
      });

    }
  });

});