How to increase unit test execution time?

Hello I am writing unit test for application having bootstrap modal popups.

The issue is modal popup has animation that took longer to open modal. When I trigger apply button click on modal that leads to exception. As modal popup not loaded.

Removing below line from bootstrap.js fix the issue but I can't change it or remove it as it in my application.

doAnimate ?
                    this.$backdrop.one($.support.transition.end, callback) :
                    callback()

To overcome this issue I have tried timeout, settimeout, delay functions but that leads to the error: Error: timeout of 2000ms exceeded

this.$fixture.find(".apply").trigger('click'); // opens modal popup

$('.apply-yes').delay(1900).trigger('click'); // clicks on apply button on modal

Please suggest an appropriate solution to problem without changing anything in bootstrap or application.