Testcase ID   test condition   Result
    1             1              true
    2             3               true
     3             4              false
     4            5               true

Precondition:let the prime no be n
case1:                 expected o/p         (prime no)result
divide the no n by 1    remainder=0                 pass
divide the no n by n    remainder=0                 pass

divide the no n by 2    remainder!=0                 pass
     .
     .
divide the no n by upto n-1 and if remanider not equal zero 
then it is a prime no.

for input = 1 , Ouput: should be "Not a Prime Number"

Prime Number(Definition): A number Greater Than 1 is called
a prime number, if it has exactly two factors, namely 1 and
the number itself.

so check with the boundary values. 
({INPUT},OUTPUT ) = ({0,1,4}, {NOT PRIME})
({INPUT},OUTPUT ) = ({2,3,5}, {is PRIME})
{Destructive INPUT}=(Type Special Characters),(Copy Past
Special Characters from a Note Pad document Using Mouse ))

0 (Zero is the only Whole Number which is not a natural number)
1