fib.py

"""
This code is in the public domain.
"""

import unittest


def fib_loop(n):
    x, y = 1, 0
    for _ in range(n):
        y, x = x, x + y
    return x


def fib_recursion(n):
    def f(m, x, y):
        return f(m - 1, x + y, x) if m > 0 else x
    return f(n, x=1, y=0)


def fib_generator():
    x, y = 1, 0
    while True:
        yield x
        y, x = x, x + y


class FibTest(unittest.TestCase):

    expected = [1, 1, 2, 3, 5, 8, 13, 21]

    def testFib(self):

        for index, n in enumerate(self.expected):
            self.assertEqual(fib_loop(index), n)
            self.assertEqual(fib_recursion(index), n)

    def testGenerator(self):
        for actual, n in zip(fib_generator(), self.expected):
            self.assertEqual(actual, n)


if __name__ == '__main__':
    print(fib_loop(input('gibe number: ')))