next_prime.py

###    Assignment   ###
#
# Your assignment is to implement the
# following function: `find_next_prime`.
# As the name states, given the number `n` the
# function should return the next closest prime.
#
# Examples:
#  * `find_next_prime(6)` should return 7.
#  * `find_next_prime(10)` should return 11.
#  * `find_next_prime(11)` should return 13.
#
# You can use whatever you want (data structures,
# language features, etc).
#
# Unit tests would be a plus.
#
### End Assignment  ###
import unittest


def find_prime_in_range(min, max):
    for number in range(min, max):
        for i in range(2, number):
            if number % i == 0:
                break
        else:
            return number
    return None


def find_next_prime(n):
    return find_prime_in_range(n + 1, 2 * (n + 1))


class FindNextPrimeTestCase(unittest.TestCase):

    def test_number_6(self):
        self.assertEqual(find_next_prime(6), 7)

    def test_number_10(self):
        self.assertEqual(find_next_prime(10), 11)

    def test_number_11(self):
        self.assertEqual(find_next_prime(11), 13)


if __name__ == '__main__':
    print find_next_prime(6)
    unittest.main()