Many a times computer science students are faced with problems whose sub-problem involves testing whether a chosen number is a prime or not.
Finding primes & proving primality
In the above link, you will find very good resources about primality testing and proving.
I have implemented an algorithm which lets you test whether a number (17 < N < 341,550,071,728,321) is a prime or not.
The link to the python code is here
The code is nicely written but not well documented. You can extend the valid limit for numbers by adding extra conditions in the code.
HOPE THIS HELPS SOMEONE.