The figures to the right show screenshots of the MASP Task Tree Simulator tool taken during testing of the task model of the cooking assistant application. For each state of the application the simulator displays the enabled task set (ETS) and layouts it conforming to the parental relationships of the task tree. For a better overview and space usage for each containment level, the simulator switches the orientation of the containers from vertical to horizontal and vice versa.

Each atomic task is depicted as a box and supports two operations: By pressing the “Mark as DONE” button a task can be marked as done, which signals the simulator to calculate the next enabled task set. By pressing the “Details” button, more detailed task information containing the textual description, the task type and attributes are visualized. Additionaly the simulator displays the domain objects that a task is able to manipulate. The simulator is also capable of generating an ETS graph visualizing possible state transitions in the application.

Beneath the possibility to check the consistency of the task flow against the original scenarios, the task simulator helps to identify deadlocks of the task flow and missing tasks. Deadlocks of the task flow can occur if there is no input interaction task left in a certain enabled task set, which results in an output interaction-only presentation that the user is unable to interact with. Such “output only” situations should only happen if the overall goal of the application has been successfully reached or an error has been occurred that can only be solved by restarting the complete application.