diff --git a/Lib/test/test_imaplib.py b/Lib/test/test_imaplib.py
index fc594b9..78bb613 100644
--- a/Lib/test/test_imaplib.py
+++ b/Lib/test/test_imaplib.py
@@ -6,7 +6,7 @@
 # depends on the timezone the machine is in.
 
 timevalues = [2000000000, 2000000000.0, time.localtime(2000000000),
-              "18-May-2033 05:33:20 +0200"]
+              '"18-May-2033 05:33:20 +0200"']
 
 for t in timevalues:
     imaplib.Time2Internaldate(t)