import unittest
from asserts import assert_equal, assert_raises, fail


def fib(n):
    if n < 0:
        raise ValueError('This algorithm works only with positive integers')
    if n == 0:
        return 0
    if n == 1:
        return 1
    return fib(n-1) + fib(n-2)


class TestFibinacci(unittest.TestCase):

    def test_0(self):
        assert_equal(fib(0), 0)

    def test_1(self):
        assert_equal(fib(1), 1)

    def test_2(self):
        assert_equal(fib(2), 1)

    def test_3(self):
        assert_equal(fib(3), 2)

    def test_4(self):
        assert_equal(fib(4), 3)

    def test_5(self):
        assert_equal(fib(5), 5)

    def test_6(self):
        assert_equal(fib(6), 8)

    def test_negative(self):
        assert_raises(ValueError, fib, -1)
        assert_raises(ValueError, fib, -42)

    def test_fail(self):
        fail('This test fails')


class TestFibinacci2(unittest.TestCase):

    def test_0(self):
        self.assertEqual(fib(0), 0)

    def test_1(self):
        self.assertEqual(fib(1), 1)

    def test_2(self):
        self.assertEqual(fib(2), 1)

    def test_3(self):
        self.assertEqual(fib(3), 2)

    def test_4(self):
        self.assertEqual(fib(4), 3)

    def test_5(self):
        self.assertEqual(fib(5), 5)

    def test_6(self):
        self.assertEqual(fib(6), 8)

    def test_negative(self):
        self.assertRaises(ValueError, fib, -1)
        self.assertRaises(ValueError, fib, -42)

    def test_fail(self):
        self.fail('This test fails')


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