added test for dividing the roots of two negative numbers and functionality to filter out corresponding math errors

src/main/py/calculations_with_roots.py

@@ -6,6 +6,8 @@ def multiplyRoots(first_number, second_number):
     return sqrt(first_number * second_number)
 
 def divideRoots(first_number, second_number):
+    if first_number < 0 or second_number < 0:
+        return -1
     return sqrt(first_number / second_number)
 
 def sqrt_power(base, exponent):

src/test/py/test_calculations_with_roots.py

@@ -21,6 +21,9 @@ class calculationsWithRoots(unittest.TestCase):
     def test_divide_sqrt_16_by_sqrt_4_should_be_2(self):
         self.assertEqual(divideRoots(16,4), 2)
 
+    def test_divide_sqrt_negative_16_by_sqrt_negative_4_should_be_negative_1_for_error(self):
+        self.assertEqual(divideRoots(-16,-4), -1)
+
     def test_sqrt_4_to_power_of_3_should_be_8(self):
         self.assertEqual(sqrt_power(4, 3), 8)