If you do test, you'll usually get your dev. Testing is important, we all know that… but it is such a chore and is not viewed as a critical element as if it seems to work, why do you need to bother with testing, 'it's working isn't it?'. What happens though for those small projects – particularly web ones – where you don't have those teams of people? They have the necessary budget to spend to ensure it all works. Great secure and reliable code (hopefully) gets released into the big wide world once everyone has signed off. This team of testers will include people from the client side who understand the requirements and purpose of the software and will know the business processes and procedures inside out. In formal, and usually large, projects run by big companies, you will find dedicated Business Analysts, Software Engineers, Systems Analysts, Developers, Designers, UX Specialists and, of course, a team of Testers covering the whole code base. The actual tests and use of Robot and Selenium are platform independent. It focuses on the installation procedures for Linux, so if you use Windows or Mac then adjust accordingly.
