2 Why We Need Model-Based Testing

234 Compositional Modeling
FSM(0, AcceptingStates(0),
Transitions(t(0,Cancel(2),0), t(0,ReqSetup(2),0), t(0,ResSetup(2),0)),
Vocabulary("ResWork", "ReqWork"))
Figure 14.8. A scnenario used to restrict the cancellation model program.
Map() Cancel(2)
ReqSetup(2,_) ResSetup(2, _, Status("Completed"))
Map(2 -> Mode("Sent"))
Cancel(2)
Map(2 -> Mode("CancelRequested"))
ResSetup(2, _, Status("Cancelled"))
ResSetup(2, _, Status("Completed"))
Cancel(2)
Figure 14.9. Composition of the cancellation model program in Figure 14.7 with the scenario in Figure 14.8.
The labels on the states show the value of mode.
FSM(0, AcceptingStates(0),
Transitions(t(0,Cancel(2),0), t(0,ReqSetup(2),0), t(0,ResSetup(2),0),
t(0,Cancel(3),0), t(0,ReqSetup(3),0), t(0,ResSetup(3),0)),
Vocabulary("ResWork", "ReqWork"))
Figure 14.10. Another scnenario used to restrict the cancellation model program.
the cancellation model program, then the complexity increases quadratically in the
number of states (is proportional to the square of the number of states) as is shown
in Figure 14.11, because the modes of distinct message IDs are independent.
14.2.4 Commands feature
The third protocol feature that we consider specifies that if a request and a response
message have the same message identifiers then the command fields must also be
the same (see Figure 14.12). The action vocabulary of this model program includes
all the action symbols besides Cancel.
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