Mutation testing is done to find the coverage of testcases.
Some mutants will be inserted in the code, then the 
negative test cases will be failed.

Plz correct me if i'm wrong

Mutation testing means testing the test cases.
ie testing the effectiveness of the testcases in finding the
error.

A testing methodology in which two or more program 
mutations are executed using the same test cases to 
evaluate the ability of the test cases to detect 
differences in the mutations.
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Mutation Testing is a fault-based testing technique
Measure the effectiveness of test cases
Assumption: a program will be well tested if all simple 
faults are detected and removed

Simple faults are introduced into the program by creating a 
set of faulty version, called MUTANTS

A mutant P’ is a program that is similar to the program P 
being tested
It differs from P only by a mutation (mutant operators)
Mutant operators example: Istruction delete, Change of a 
constant value, Change of a variable 

Test cases are used to execute these mutants with the goal 
of causing each mutant P’ to produce incorrect output
If  P’ produce different results from P, running the same 
test case T  Mutant killed

Hi,
 In the Mutation testing we create a copy of the original
program that is called as mutant,and we do some changes in
the mutant program and run it with the test cases.After
going through the test cases if the change is being detect
by the test sace then it is called as a 'Killed Mutant' and
if the change did not detect by the test cases then it is
called as 'Equivalent Mutant'. This process is expensive.

Plz correct me if i m wrong....
Thnks n Regards..
Nitin Verma 
nitin9360@gmail.com

When a major changes occurred in the coding due to the 
change requirement by the customer is called mutation 
testing.

Testing the quality of the automation script by purposefully
introducing a defect into the application

Mutation testing (sometimes also called mutation analysis) 
is a method of software testing, which involves modifying 
program's source code in small ways

Monkey testing:-monkey testing is a testing that runs with 
no specific test in mind. The monkey in this case is the 
producer of any input data (whether that be file data, or 
input device data). 
Keep pressing some keys randomly and check whether the 
software fails or not.