diff --git a/Lib/test/test_asyncore.py b/Lib/test/test_asyncore.py
index d5e6fa3a016..7d1a3cb33ff 100644
--- a/Lib/test/test_asyncore.py
+++ b/Lib/test/test_asyncore.py
@@ -330,7 +330,7 @@ class DispatcherTests(unittest.TestCase):
         if hasattr(os, 'strerror'):
             self.assertEqual(err, os.strerror(errno.EPERM))
         err = asyncore._strerror(-1)
-        self.assertIn("unknown error", err.lower())
+        self.assertTrue(err != "")
 
 
 class dispatcherwithsend_noread(asyncore.dispatcher_with_send):