Software Engineering for Students A Programming Approach

Exercises 279
In black box (or functional) testing, sample data based on the specification is used.
This is termed equivalence partitioning.
In white box (or structural) testing, the internal structure of the software is used
to select test data. This means that every path through the program is tested.
Unit testing tests each component in isolation. Drivers and stubs are used to substitute
for missing components. Integration testing tests components as they are
brought together.
19.1 Consider a program that has 16 if-then statements in it. Then there are 216 •
Exercises
possible
paths through it. If each test takes 50 microseconds and each action takes 50
microseconds (a gross underestimate), how much computer time is needed to test all
program paths?
19.2 Devise black box and white box test data to test the following program. The program
specification is:
The program inputs a series of integers from the keyboard using a text field. The
program finds the largest of the numbers. The numbers are terminated when a button
labeled Start Again is pressed.
Try not to look at the text of the program, given below, until you have completed the
design of the black box data.
The program involves the following class:
class Biggest {
private int largest;
}
public Biggest() {
largest = 0;
}
public void nextNumber(int n) {
if (n > largest)
largest = n;
}
public void display(TextField textField) {
textField.setText("largest so far is" + largest);
}
public void startAgain() {
largest = 0;
}