The document discusses responsive web design layout testing using the Galen Framework with Selenium. It provides an overview of responsive web design, the Galen Framework which allows defining element relationships and expected layouts in a specification language to test responsiveness across viewports and platforms. It also discusses how idealo uses agile development practices and a testing stack including Selenium, JUnit, Maven and Jenkins to integrate layout testing into their build and deployment process using Galen. The document concludes with noting some lessons learned from using Galen at idealo.