Actually its quite hard to tell what Galen Framework is. It all began with the need for testing website on different browsers. I had to check whether my website is acting weird in IE, Chrome, Firefox, Opera etc. Then the Responsive Design trend came in and now suddenly I get more work. I have to stretch my browser to check if the layout is broken or not for mobile and tablet versions. And even having WebDriver and Selenium Grid at that time did not really help to solve my problem with testing. One of the ideas I tried to implement was like this: tests were making screenshots of the same page in different browsers and then later these screenshots were added to one big report. Later one of the QA engineers had to quickly go through the report and look for something suspicious. This idea didn’t live for a long time. At some point we had to throw it away. Especially it became useless when Responsive Design kicked in. I needed a special tool that would allow me to express how I see my website on different devices so later I could use it as a document as well as executable test. Thats how I came up with Galen Framework. The idea was quite simple – just take a location and dimensions of element and verify it relatively to other elements on page.
In short – Galen Framework is a special language and a tool for testing website layout in a real browser. Or even more short – Galen Framework allows to test Responsive Design and Cross-Browser Html Layout.