Behavior-Driven Development (BDD9 and Acceptance Testing are heavily intertwined and in many aspects are one and the same. Both focus on starting at the outer layers of your application by concentrating on what matter to users; behavior.
Learn how testing can be used both for specifying your application yet to be develop expected behavior and as accurate, running documentation that can be used to validate your stakeholder’s acceptance criteria. This video discusses the different types of testing and presents a few hands-on exercises to flesh out a Rails application with the RSpec and Capybara open source tools for software testing.
Video producer: http://www.railsconf.com/