sqrt_test.py

import unittest

from maths import sqrt


class SqrtTest(unittest.TestCase):
    def test_sqrt_0(self):
        self.assertEqual(0.0, sqrt(0.0))

    def test_sqrt_minus1(self):
        self.assertRaisesRegex(Exception, 
                               'Input to sqrt must be a positive number', 
                               lambda: sqrt(-1))

    def test_sqrt_1(self):
        self.assertEqual(1.0, sqrt(1))

    def test_sqrt_4(self):
        self.assertEqual(2.0, sqrt(4.0))

    def test_sqrt_6point25(self):
        self.assertEqual(2.5, sqrt(6.25))


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