_Based on [Project Euler problem 35](https://projecteuler.net/problem=35)_

A circular prime is a prime in which every circular permutation of that number is also prime. Circular permutations are created by rotating the digits of the number, for example: `197, 971, 719`. One-digit primes are circular primes by definition.

Complete the function that dertermines if a number is a circular prime.

There are 100 random tests for numbers up to 10000.