fib_test.py

import unittest


def fib(n: int):
    return n if n < 2 else fib(n - 1) + fib(n - 2)


class TestFibonacciFunction(unittest.TestCase):
    def test_big_fibonacci(self):
        self.assertEqual(fib(10), 55)

    def test_small_fibonacci(self):
        self.assertEqual(fib(1), 1)


if __name__ == "__main__":
    unittest.main()