Software Engineering and Testing

SOFTWARE TESTING 171

to M

a

. Similarly, driver D

3

for cluster 3 is removed prior to integration with

module M

b

. Both M

a

and M

b

will ultimately be integrated with component M

c

and so forth.

As integration moves upward, the need for separate test drivers lessens. In fact,

if the top two levels of program structure are integrated top-down, the number

of drivers can be reduced and integration of clusters is greatly simplified.

4. Regression Testing. Regression testing is the activity that helps to ensure that

changes (due to testing or for other reasons) do not introduce unintended

behavior or additional errors.

The regression test suite contains three different classes of test cases:

 Additional tests that focus on software functions. ...