added test for identify if function is constant and simplify it as well as corresponding functionality

src/main/py/read_math_function.py

@@ -49,5 +49,5 @@ def calculate_constant_string(string):
 def simplify_easy_math_function(type, function):
     if type != "v":
         return False
-    if is_string(function) == False:
-        return function
+    if is_string(function) == False or is_allowed_string("c", function) == True:
+        return simplify_constant("c", function)

src/test/py/test_read_math_function.py

@@ -36,6 +36,8 @@ class read_function(unittest.TestCase):
         self.assertEqual(simplify_easy_math_function("a", "42x"), False)
     def test_easy_function_number_as_function_return(self):
         self.assertEqual(simplify_easy_math_function("v", 42), 42)
+    def test_easy_function_string_is_constant(self):
+        self.assertEqual(simplify_easy_math_function("v", "42^(2)+1-3*4/3"), 1761)
 
 if __name__ == '__main__':
     unittest.main()