## Friday, July 26, 2013

### PPT On BLACK BOX TESTING TECHNIQUES

Presentation On BLACK BOX TESTING TECHNIQUES

BLACK BOX TESTING TECHNIQUES Presentation Transcript:
1.BLACK BOX TESTING TECHNIQUES

2.INTRODUCTION
The term black box refers to the software which is treated as a black box.
The system or source code is not checked at all. It is done from customer’s viewpoint.
The test engineer engaged in black box testing only knows the set of inputs and expected outputs and is unaware of how those inputs are transformed into outputs by the software.

3.Boundary Value Analysis (BVA)
It is a black box testing technique that believes and extends the concept that the density defect is more towards the boundaries. This is done to the following reasons:
Programmers usually are not bale to decide whether they have to use <= operator or < operator when trying to make comparisons.
Different terminating conditions of for-loops, while loops and repeat loops may cause defects to move around the boundary conditions.
The requirements themselves may not be clearly understood, especially around the boundaries thus causing even the correctly coded program to not perform the correct way.

4.What is BVA?
The basic idea of BVA is to use input variable values at their minimum, just above the minimum, a nominal value, just below their maximum and at their maximum.
BVA is based upon a critical assumption that is known as single fault assumption theory.
We derive the test cases on the basis of the fact that failures are not due to simultaneous occurrence of two faults. So, we derive test case by holding the values of all but one variable at their nominal values and letting that variable assume its extreme values.

5.Limitations of BVA
Boolean and logical variables present a problem for Boundary value analysis.
BVA assumes the variables to be truly independent which is not always possible.
BVA test cases have been found to be rudimentary because they are obtained with very little insight and imagination.

6.Before we generate the test case, firstly we need to give the problem domain:
Problem Domain: the triangle program accepts three integers, a, b and c as input. These are taken to be the sides of a triangle. The integers a, b and c must satisfy the following conditions:

7.How to generate BVA Test Cases?
We know that our range is [1,200] where 1  is the lower bound and 200 being the upper bound also, we find that this program has three inputs – a, b and c. So, for our case

BVA yields (4n+1) test cases, so we can say that the total number of test cases will be (4=3+1) = 12 + 1 = 13.

We draw the table now which shows those 13 test-cases.

8.BVA test cases for triangle problem

9.EQUIVALENCE CLASS TESTING
The use of equivalence classes as the basis for functional testing has two motivations:
We want exhaustive testing and
We want to avoid redundancy.
This is not handled by BVA technique as we can see massive redundancy in the tables of test cases.
The idea of equivalence class testing is to identify test cases by using one element from each equivalence class.

10.DECISION TABLE BASED TESTING
Of all the functional testing method, those based on decision tables are the most rigorous because decision tables enforce logical rigour.