Issue #14442: Add missing errno import in test_smtplib.
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 05d97ef..18dde2f 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -9,6 +9,7 @@
 import sys
 import time
 import select
+import errno
 
 import unittest
 from test import support, mock_socket