diff --git a/test_calculator.py b/test_calculator.py
index 7cb79e9..8adeda1 100644
--- a/test_calculator.py
+++ b/test_calculator.py
@@ -9,6 +9,11 @@ def setUp(self):
     def test_add(self):
         self.assertEqual(self.calc.add(2, 3), 5)
 
+    def test_addition_zero(self):
+        """Test the add function with zero."""
+        result = self.calc.add(0, 0)
+        self.assertEqual(result, 0)
+
     def test_sub(self):
         self.assertEqual(self.calc.subtract(2, 3), -1)