Added test for addition functionality to test addition of decimal numbers

src/test/py/test_primitive_calculations.py

@@ -18,6 +18,9 @@ class primitive_calculations(unittest.TestCase):
     def test_add_5_plus_minus_5_equls_0(self):
         self.assertEqual(add(5, -5), 0)
 
+    def test_add_1_dot_5_plus_1_dot_5_equals_3(self):
+        self.assertEqual(add(1.5, 1.5), 3)
+
 
 if __name__ == "__main__":
     unittest.main()