Feature-based Development of State Transition Diagrams with Property Preservation

In this paper, we consider incremental development of state transition diagrams by adding features, which add new states and transitions. The goal is to capture when properties of a state transition diagram are preserved when adding a feature. We classify several typical cases of such state transition diagram extensions and show when commonly used properties are preserved. In some cases, we add restrictions to the input events. In others, we need to transform properties to account for new failure cases. Properties are specified on the externally visible input and output events. To formalize the properties and to reason about internal state transition diagram extensions we use a computation tree logic with states and events.