Page 212 - DCAP405_SOFTWARE_ENGINEERING

Unit 12: Testing Tactics

Notes

Did u know? What are Tools used for Black-box Testing?
Tools used for Black-box testing largely depends on the type of black box testing your are
doing.
 For Functional/Regression Tests you can use – QTP

 For Non-Functional Tests you can use – Loadrunner
This technique is applied at a later stage unlikely to the white-box testing approach. Using this
technique, we can arrive at test cases that satisfy the following criteria:
1. test cases that reduce the total test cases by a large quantity to achieve reasonable testing
and
2. test cases that tell us something about the presence or absence of a variety of errors rather
than a particular kind of error.
The techniques are as below.

Boundary Value Analysis

The art of testing is to come up with a small set of test cases such that the chances of detecting an
error are maximized while minimizing the chances of creating redundant test cases that uncover
similar errors. It has been observed that the probability of finding errors increases if the test
cases are designed to check boundary values.
Consider a function F with x and y as two input variables. These inputs will have some boundaries:
a<=x<=b
p<=y<=q

Hence, inputs x and y are bounded by two intervals [a,b] and [p,q] respectively. For x, we can
design test cases with values a and b, just above a and b and just below a and b which will have
higher chances to detect errors. Similar is the case for y. This is represented in the Figure 12.5.
Figure 12.5: Input Domain of a Function
of Two Variables

y

q

p

a b x

Boundary value test cases are obtained by keeping one variable at its extreme and the other at its

nominal value. At times we might want to check the behavior when the value of one variable

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