refactoring: corrected test description

src/test/py/test_primitive_calculations.py

@@ -9,7 +9,7 @@ class primitive_calculations(unittest.TestCase):
     def tearDown(self):
         pass
 
-    def test_add_5_plu_5_equals_10(self):
+    def test_add_5_plus_5_equals_10(self):
         self.assertEqual(add(5, 5), 10)