Question

7. Which test case below can kill the mutant?

Mutant:

int x = read(); // x is the input

x = 2*x;

if (x > 5){

    printf(“%d”, x);

}else{

            print(“%d”, x/2); // Original: print(“%d”, x-2);

}

A. x = 4

B. x = 3

C. x = 2

D. x = 1

Answer 1

D) x = 1 is the answer.

A mutant is said to be killed, when the test suite is able to detect the changes.

Here we are performing Mutation testing by changing the operator '-' with '/'.

We have to calculate output for both the operators '-' and '/' with four inputs(1,2,3,4). If the outputs are same in both cases, Mutant is not killed.

Let's check this out

O/P using '/' operator O/P using '-' operator

x = 4 8 8 (No change)

x = 3 6 6 (No change)

x = 2 2 2 (No change)

x = 1 1 0 (Change)