wraith
Wraith is a responsive webpage screenshot comparison tool designed for visual regression testing. It uses headless browsers, Imagemagick and Ruby to enable fast feedback for front end changes that reduces manual testing and user facing bugs.
Licence
Apache
Source
Gems
Documentation
Wraith
Wraith uses either PhantomJS, CasperJS and SlimerJS to create screen-shots of webpages on different environments and then creates a diff of the two images, the affected areas are highlighted in blue.
Wraith is a Ruby gem with a simple command line interface for developers, testers or anyone interested in visual regression testing. Wraith can select entire pages, or a specific CSS selector on a page for targeted testing of components across multiple pages and environments.
Wraith has several modes of operation, direct comparison of 2 websites, a history mode for rapid developer feedback or a spider mode for crawling a website.