Black Box – Robust Testing in software testing

By: Prof. Dr. Fazal Rehman Shamil | Last updated: November 12, 2022

Black Box – Robust Testing in software testing

In robustness testing, the software is tested by giving invalid values as inputs. Robustness testing is usually done to test exception handling.

In robust boundary value testing,  we make combinations in such a way that some of the invalid values are also tested as input.

The type of testing done by causing the software or system to fail in order to test the robustness is called robustness testing.

Robust Boundary value testing on 3 variables:

How to test robustness of a software

Robust Testing Blac Box Testing analysis software testing

Suppose we have  3 variables X, Y and Z to test

The range of X: 0 to 100

The range of Y: 20 to 60

The range of Z: 80 to 100

       Xyz
Min-     -11979
Min02080
Min+12181
Nominal504090
Max-995999
Max10060100
Max+10161101

Figure: Testing points detected in Simple Robust Boundary Value Testing

Test Cases:

Total Test cases =

(Number of variables * Number of testing points without nominal )+ (1 for  Nominal)

These testing points are min-, min, min+, max- and max and max+

19=(3*6)+1

We can generate 19  test cases from both variables X, Y, and Z.

  • There are a total of 3 variables X, Y and Z
  • There are 6 possible values like min-, min, min+, max-, max and max+
  • 1 is for nominal

Logic:

When we make test cases, we will fix the nominal value of the two variables and change the values of the third variable.

For example

  • We will fix the nominal values of X and Y and make a combination of these values with each value of the Z variable.

Fix nominal values of X and Y are 50,40, and we will compare these two values with 79, 80,81,90,99,100 and 101.

  • We will fix the nominal values of X and Z and will make a combination of these values with each value of the Y variable.

Fix nominal values of X and Z are 50, 90, and we will make a combination of these two values with 19, 20,21,40,59,60 and 61.

  • We will fix the nominal values of Y and Z and will make a combination of these values with each value of the X variable.

Fix nominal values of Y and Z are 40, 90, and we will make a combination of these two values with -1, 0,1,50,99,100 and 101.

Test Case#XYZComment
1504079Fix Nominal of X and Y
2504080Fix Nominal of X and Y
35040
81Fix Nominal of X and Y
4504090Fix Nominal of X and Y
5504099Fix Nominal of X and Y
65040100Fix Nominal of X and Y
75040101Fix Nominal of X and Y
8501990Fix Nominal of X and Z
9502090Fix Nominal of X and Z
10502190Fix Nominal of X and Z
11505990Fix Nominal of X and Z
12506090Fix Nominal of X and Z
13506190Fix Nominal of X and Z
14-14090Fix Nominal of Y and Z
1504090Fix Nominal of Y and Z
1614090Fix Nominal of Y and Z
17994090Fix Nominal of Y and Z
181004090Fix Nominal of Y and Z
191014090Fix Nominal of Y and Z

Figure: Test cases generated in Robust simple Boundary Value Testing.

Video Lecture

Another Example of robust boundary value software testing

nominal
min-
min
min+
max-
max
max+
X
7
4
5
6
8
9
10
Y
66
43
44
45
87
88
89
Z
51
2
3
4
98
99
100

 

test casesXYZ
17662
27663
37664
476651
576698
676699
7766100
874351
974451
1074551
1178751
1278851
1378951
1446651
1556651
1666651
1786651
1896651
19106651

Download slides of Robustness Testing PPT

Download PDF of Robustness Testing pdf

Advantages of robustness testing

There are many benefits of robustness testing. Some of the benefits are mentioned below;
1. Better project analysis
Robustness testing means to increase the study of what has already been analyzed about your product. The robustness testing extends the area of testing of the previously tested software components. Robustness testing also test invalid values to satisfy the testing level.
3. Better design
The robustness testing result in more options and better software designs and it is completed before the finalization of the design of the product.
4. Achieve consistency
Robustness testing helps to increase the consistency, reliability, accuracy and efficiency of the software.

Frequently Asked Questions (FAQ)

What does robustness mean in hypothesis testing?
Robustness is the strength of a tests, and procedures according to the specific conditions of the statistical analysis a study hopes to achieve the goals.

Leave a Reply