Foundations of Software Testing: Fundamental Algorithms and Techniques

Test-Adequacy Assessment Using Control Flow

loop. The remaining subscripted nodes indicate edges along which

the values of y are propagated. An explanation follows.

Variable y is defined at node 6 when subpath < 1, 2, 3, 6

1

> is

traversed. This value of y is used in the decision at node 3 when <

6

1

, 2, 3

1

, 4

1

> is traversed. Note that edge (3, 4) is now covered as

there is a def–clear path < 2, 3 > from node 6 to edge (3, 4).

Next, path < 6

2

, 2, 3

2

, 6

2

, 7 > is traversed where y is defined once

again at node 6. This definition of y propagates to edge (3,6) via the

def–clear path < 2, 3

2

, 6

2

>. The control now moves to node 7 and

the program execution terminates ...