added test for calculating string with pow as well as corresponding functionality

src/main/py/read_math_function.py

@@ -1,3 +1,5 @@
+import math
+
 def read_constant(type, value):
     if type != "c":
         return False
@@ -13,6 +15,7 @@ def is_allowed_string(type, value):
     return all(character.isdigit() or character in allowed for character in value)
 
 def calculate_string(string):
+    string = string.replace('^', '**')
     try:
         return eval(string)
     except Exception as e:

src/test/py/test_read_math_function.py

@@ -17,6 +17,8 @@ class read_function(unittest.TestCase):
         self.assertEqual(is_allowed_string("c", "42^(2)+1-3*4/3x"), False)
     def test_constant_calculate_without_pow(self):
         self.assertEqual(calculate_string("42+1-3*4/3"), 39)
+    def test_constant_calculate_with_pow(self):
+        self.assertEqual(calculate_string("42^(2)+1-3*4/3"), 1761)
 
 if __name__ == '__main__':
     unittest.main()