A processor is configured to execute an event-driven program along a plurality of execution paths. Each of the plurality of execution paths is determined by randomly chosen outcomes at non-deterministic points along the plurality of execution paths. A memory is configured to store values of properties of the event-driven code in response to executing the event-driven program along the plurality of execution paths. The processor is also configured to infer normal ranges of the properties of the event-driven program based on the values stored in the memory.