diff --git a/test_time_to_first_response.py b/test_time_to_first_response.py
index 79bf353..0cd4843 100644
--- a/test_time_to_first_response.py
+++ b/test_time_to_first_response.py
@@ -86,6 +86,31 @@ def test_measure_time_to_first_response_ignore_users(self):
         # Check the results
         self.assertEqual(result, expected_result)
 
+    def test_measure_time_to_first_response_only_ignored_users(self):
+        """Test that measure_time_to_first_response returns empty for an issue with only ignored users."""
+        # Set up the mock GitHub issues
+        mock_issue1 = MagicMock()
+        mock_issue1.comments = 1
+        mock_issue1.created_at = "2023-01-01T00:00:00Z"
+
+        # Set up the mock GitHub comments (all ignored)
+        mock_comment1 = MagicMock()
+        mock_comment1.user.login = "ignored_user"
+        mock_comment1.created_at = datetime.fromisoformat("2023-01-02T00:00:00Z")
+
+        mock_comment2 = MagicMock()
+        mock_comment2.user.login = "ignored_user2"
+        mock_comment2.created_at = datetime.fromisoformat("2023-01-03T00:00:00Z")
+
+        mock_issue1.issue.comments.return_value = [mock_comment1, mock_comment2]
+
+        # Call the function
+        result = measure_time_to_first_response(mock_issue1, None, ["ignored_user", "ignored_user2"])
+        expected_result = None
+
+        # Check the results
+        self.assertEqual(result, expected_result)
+
 
 class TestGetAverageTimeToFirstResponse(unittest.TestCase):
     """Test the get_average_time_to_first_response function."""