Get factorial

Formula: N! = N * (N - 1)!

import sys

def factorial_recursion(N):
    ''' Get factorial for a given N [recursion] '''
    if N < 1:
        return 1
    else:
        return N * factorial_recursion(N - 1)

def factorial_regular(N):
    ''' Get factorial for a given N [regular] '''
    fact, x = 1, 2
    while x <= N:
        fact *= x
        x += 1
    return fact

# test

def test_fact(fact_algorithm, display = False):

    print("Testing: ", fact_algorithm.__doc__)
    N = 10

    print("testcase #1:")
    N = 10
    Fact_10 = 3628800
    Res = fact_algorithm(N)
    if display:
        # Display factorials from 1 to N
        for i in range(1, N + 1):
            print ('{}! = {}'.format(i, fact_algorithm(i)))

    print("Ok" if Res == Fact_10 else "Fail")
    # print("System stack depth = {}".format(sys.getrecursionlimit()))

if __name__ == "__main__":
    # Factorial
    test_fact(factorial_recursion)
    print("=" * 40)
    test_fact(factorial_regular, display=True)

Output:

testcase #1:
1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040
8! = 40320
9! = 362880
10! = 3628800