Scenario simulation

Scenario simulation consists of running UCEd simulator using the scenario triggers, guard realizations and waiting delays to drive the simulation. System reactions are compared with the actual reactions produced by simulation; and assertions are used to check reached states.
Notice that a scenario need to be validated before its simulation.

The following shows a scenario simulation result.

Figure 7.3: Scenario simulation result.

Simulation output is displayed in the scenario model editor tool message area. A scenario simulation proceeds according to the follow.

• The simulation is initiated from the state chart initial state, and the scenario elements considered in sequence.

  The conditions corresponding to the current simulation state are displayed before each of the scenario actions.

• A trigger is simulated by checking if there is a transition on it from the current simulation state. If so, and if the transition guards are satisfied, all the reactions are checked with the system reactions that immediately follow in the scenario.
  • A scenario fails and an error message is displayed if a trigger can not be fired.
  • If a scenario doesn't specify system reactions, any actual system reactions following a trigger are just displayed in the simulation output.
  • If a scenario includes system reactions different to those obtained from the state model, a warning message is displayed but the simulation continues normally.
• When a state from which there are outgoing transitions with guards is reached, there must be a guard realization in the scenario at that point in the course of the simulation such that a single outcome is selected. An error message is displayed and the simulation fails when a selection is not possible.
• For a timeout to be simulated, there needs to be a waiting delay equal or greater that the timeout delay when the timeout transition is reached.