Schaum's Outline Series

202
Since a regular expression can be mapped to a finite state machine, these two
approaches are equivalent. Although the finite state machine used to describe the
behavior of a software system may not be minimal, having additional states will
increase the effectiveness of the test set.
EXAMPLE 13.2
Identifythe function pair testing coverage for the linked list of rectangles program
of Example 13.1. Consider the calling structure of the functions.
class point
point()
getx()
gety()
class rectangle
rectangle()
point()point()point()point()
length()
getx()getx()gety()gety()
area()
length()length()
class linklistnode
linklistnode()
getNext()
getRectangle()
setnext()
class rectanglelist
rectanglelist()
addRectangle()
rectangle()linklistnode()setnext()
totalArea()
(getRectangle()area()getNext())*
CHAPTER 13 Object-Oriented Testing
Most of the regular expressions for the individual functions have a fixed list of
method calls. Onlythe totalArea function is zero-or-more repetition from the
while loop.
Putting all of these together into one regular expression and considering that the
rectanglelist has to be created first and then addRectangle or totalArea
could be done gives the following regular expression:
rectanglelist ((addRectangle rectangle point point point point
linklistnode setnext) | (totalArea (getRectangle area length getx getx
gety gety length getx getx gety gety getNext)*)
The function pair testing can be achieved bythe following test sets:
1. Creating one rectangle, and then calculating the area
2. Creating two or more rectangles, and then calculating the area
3. Not creating anyrectangles, and then calculating the area
4. Creating rectangles after calculating the area