state-transition-testing

Model a system as states connected by event-triggered transitions, and find the (state, event) combinations nobody has defined — missing transitions, unreachable states, trap states, and undefined invalid-transition handling. Use eagerly whenever the user describes an entity with a status field that changes based on events (order lifecycle, payment states, approval workflows, auth flows, wizard/multi-step forms, protocol states) and wants to find gaps in the transition logic, or asks "what transitions are we missing", "can this get stuck", "map out this state machine", or "what happens if this event fires in the wrong state". If the problem is really about combinations of independent input parameters rather than a stateful entity, the scenario-design skill can route elsewhere.