first program

 

fault:

 we can not reach the first element. the conditional statement should be i >= 0;

a test case that does not execute the fault:  x=null;

a test case that execute the fault, but does not result in an erroe state: x={3,4,5},y=5;

a test case that results in an error, but not a failure: x={3,4,5},y=1;

 

 

second program

 

fault:

it would found the first zero, the conditional statement should be(int i=x.length -1; i>=0; i-- )

a test case that does not execute the fault:  x=null;

a test case that execute the fault, but does not result in an erroe state: x={0}

a test case that results in an error, but not a failure: x={3,4,5}