Behaviour-driven development is an “outside-in” methodology. It starts at the outside by identifying business outcomes, and then drills down into the feature set that will achieve those outcomes. Each feature is captured as a “story”, which defines the scope of the feature along with its acceptance criteria. This article introduces the BDD approach to defining and identifying stories and their acceptance criteria.
Scenario thinking is a tool for motivating people to challenge the status quo, or get better at doing so, by asking "What if?" Asking "What if?" in a disciplined way allows you to rehearse the possibilities of tomorrow.