added test for premultiplicator for simplify_exponential_function

src/test/py/test_read_math_function.py

@@ -73,6 +73,9 @@ class ReadFunction(unittest.TestCase):
     def test_simplify_exponential_function_exponent_not_1_not_0(self):
         self.assertEqual(simplify_exponential_function("e", "x^2"), ["2x"])
 
+    def test_simplify_exponential_function_premultiplicator(self):
+        self.assertEqual(simplify_exponential_function("e", "2x^2"), ["4x"])
+
 
 if __name__ == '__main__':
     unittest.main()