added test to use sqrt_power with zero as exponent

src/test/py/test_calculations_with_roots.py

@@ -27,6 +27,8 @@ class calculationsWithRoots(unittest.TestCase):
     def test_sqrt_16_to_power_of_point5_should_be_2(self):
         self.assertEqual(sqrt_power(16, 0.5), 2)
 
+    def test_sqrt_16_to_power_of_0_should_be_1(self):
+        self.assertEqual(sqrt_power(16, 0), 1)
 
 if __name__ == '__main__':
     unittest.main()