from unittest import main, TestCase
from fib_py.fib_calc.fib_number import recurring_fibonacci_number


class RecurringFibNumberTest(TestCase):
    def test_zero(self):
        self.assertEqual(0, recurring_fibonacci_number(number=0))

    def test_negative(self):
        self.assertEqual(
            None, recurring_fibonacci_number
            (number=-1)
        )

    def test_one(self):
        self.assertEqual(1, recurring_fibonacci_number(number=1))

    def test_two(self):
        self.assertEqual(1, recurring_fibonacci_number(number=2))

    def test_twenty(self):
        self.assertEqual(6765, recurring_fibonacci_number(number=20))


if __name__ == "__main__":
    main()