1. Random Testing
Can KAYA
201171221
SQA&Testing – Cankaya University
Ankara-TURKEY
November 28,2012

2. Outline
 Who invented Random Testing ?
 What is Random Testing ?
 Why we use RT ?
 How we use RT?
 Main types of random testing techniques
 When we use RT ?
 Example
 Where we use RT ?
 Pros & Cons
 RT Tools

4. Spesification-Based
Techniques
 Equivalance partitioning
 Boundary value analysis
 Decision table
 Finite-state machine method
 Testing from formal spesification
 Random testing

5. Who invented Random
Testing ?
Random testing was mentioned
first time in the The Art Of
Software Testing
book of Glenford J. Myers in 1979

6. What is Random Testing ?
 All of the test inputs are generated randomly (often
using a tool).
 İt is a black box testing

7. Why we use RT ?
• Random testing gives us an advantage of easily
estimating software reliability from test outcomes.
Test inputs are randomly generated according to
an operational profile, and failure times are
recorded
• The data obtained from random testing can then be
used to estimate reliability. Other testing methods
cannot be used in this way to estimate software
reliability
• Use of random test inputs may save some of the
time and effort that more thoughtful test input
selection methods require.(domain is well-
structured)

8. How we use RT?
Random Testing can be summarized as a four-
step procedure
1. The input domain is identified
2. Test inputs are selected independently from the
domain
3. The system under test is executed on these inputs.
This inputs constitude a random test set.
4. The results are compared to the system
spesification. The test is a failure if any input leads
to incorrect results; otherwise it is a success.

9. Main types of random
testing techniques:
1. Random input data generation
2. Random sequence of data input (sometimes
called as stochastic testing)
3. Random data selection from existing database
It is possible to combine all the above testing techniques.

10. When we use RT ?
• If we have a lot time and we want to more reliability
product.
• If we dont have enought time to testing
product, but we must to test it.
• We must consider the time needed to write a
random test generator vs the time to write a set of
directed tests(or generators).
• We doing random testing ensure that our tests are
sufficiently random, and they cover specifications.

11. Example:
• For example, if the valid input domain for a module integers
between 1 and 100, the tester using this approach would
randomly, or unsystematically, select values from within that
domain; for example, the values 55,24,3 mighht be chosen.
Given this approach, some of the issues that remain open are
the following:
• Are the three values adequate to show that the module
meets its specification when the tests are run ? Should
additional or fewer values be used to make the most effective
use of resources ?
• Are there any input values, other than those selected, more
likely to reveal defects ? For example, should positive integers
at the beginning or end of the domain be specifically
selected as inputs ?
• Should any values outside the valid domain be used as test
inputs? For example, should test data include floating point
values, negative values, or integer values greater than 100 ?

12. Where we use RT ?
• Random Testing techniques are applicable for any
single project. They will change from project to
project.
• Usually required for the current project testing
techniques are described in the test plan.
• Different testing techniques can find different types
of defects.

13. What is benefit ?
• If the domain is well-structured, automatic
generation can be used, allowing many more test
cases to be run than if tests are manually
generated.
• We can give surprisingly good result by using
correct alghorithm of course if the domain is well-
structured

14. RT has the following
weakness
• They are not realistic
• Many of the tests are redundant and unrealistic
• You will spend more time analyzing results
• You cannot recreate the test if you do not record
what data was used for testing
• There is no measure of risk
• Random testing is, of course, the most used and
least useful method

15. RT Tools
• Jcheck
• Randoop
• Yeti-TEST
• A Lightweight Tool

16. References
• Software Testing and Quality Assurance: Theory and
Practice By Sagar Naik, Piyu Tripathy
• Software Testing By Koirala Koirala, Sheikh Sheikh
• Practical Software Testing: A Process-Oriented
Approach By Ilene Burnstein
• http://c2.com/cgi/wiki?RandomTesting
• http://extremesoftwaretesting.com/Techniques/Ran
domTesting.html

17. Any Question ?