Model-Based Testing for Embedded Systems

28 Model-Based Testing for Embedded Systems

1

?x,y,z

x > y

Yes

No

x < 2z

Yes

No

2

!x

3

!y

4

!z

FIGURE 2.6

State machine with internal variables.

1

!x,y,z

FIGURE 2.7

Prefix of the state machine when inverted.

1

x = rnd(−10,10),...!x,y,z

FIGURE 2.8

Randomized input selection strategy.

This model cannot be inverted into a tester model directly in the same manner as we

inverted the finite-state machine in the previous section because the inverted model would

start with the prefix shown in Figure 2.7.

Notably, the variables x, y, and z would be unbound—the transition cannot be executed.

A simple way to bind the variables would be to use a random testing approach (Duran

and Ntafos ...