added test for returning a single constant as well as corresponding functionality

src/main/py/read_math_function.py

@@ -0,0 +1,3 @@
+def read_constant(type, value):
+    result = value
+    return result

src/test/py/test_read_math_function.py

@@ -0,0 +1,10 @@
+import unittest
+from src.main.py.read_math_function import *
+
+
+class read_function(unittest.TestCase):
+    def test_constant_without_calculation(self):
+        self.assertEqual(read_constant("c", 42), 42)
+
+if __name__ == '__main__':
+    unittest.main()