YUI recommends YUI 3.

YUI 2 has been deprecated since 2011. This site acts as an archive for files and documentation.

Asynchronous Event Testing

This example shows how to create an asynchronous test with the YUI Test framework for testing browser-based JavaScript code. A TestCase object is created to test the Anim object. The test waits until the animation is complete before checking the settings of the animated element.