Component Patchtester for Testers
From Joomla! Documentation
The patch tester component is an extension for Joomla! that allows users to quickly apply changes from GitHub pull requests and test them.
Downloads of the component can be found at: https://github.com/joomla-extensions/patchtester/releases
You can see a video tutorial here: http://www.youtube.com/watch?v=4OWgusZgIfk&feature=youtube_gdata
The patch tester component was originally created by Ian MacLennan, and has been improved by Nikolai Plath, Michael Babker and Roland Dalmulder.
The source code and issue tracker for the extension can be found on GitHub at: https://github.com/joomla-extensions/patchtester