Foundations of Software Testing: Fundamental Algorithms and Techniques

Test Generation

Now suppose that the Withdraw module has been modified to im-

plement a change in withdrawal policy, for example “No more than

$300 can be withdrawn on any single day.” We now have the modified

SATM



to be tested for the new functionality as well as to check if

none of the existing functionality has broken. What tests should be

rerun ?

Assuming that no other module of SATM has been modified,

one might propose that tests t

1

and t

2

need not be rerun. This is a

risky proposition unless some formal technique is used to prove that

indeed the changes made to the Withdraw module cannot affect the

behavior of the remaining modules.

Let us assume that the testers are convinced that the changes in

SATM will not affect any module other than Withdraw.