This workshop will serve as an introduction Mozmill test scripting. The goal is to introduce Mozmill to attendees, learn the basics of writing automated user-based tests for Mozmill, and to write a test script of their own. Mozmill is a UI testing tool for all Mozilla based applications. Work began on the tool in summer of 2008, and it reached 1.0 in early 2009. It is implemented as an Add-On, and is written primarily in JavaScript. Mozmill presents a medium for contributors to provide automated tests to the project with a very shallow learning curve. The benefits of which extend past Firefox and Thunderbird to other Mozilla-based application developers and add-on developers. The workshop will lead into a Mozilla-run test day. This will give attendees the opportunity to contribute test scripts throughout the remainder of FSOSS to the Mozilla Project.