Add a missing import.
diff --git a/Lib/test/test_dl.py b/Lib/test/test_dl.py
index a3f04ea..6069a77 100755
--- a/Lib/test/test_dl.py
+++ b/Lib/test/test_dl.py
@@ -2,6 +2,7 @@
 """Test dlmodule.c
    Roger E. Masse  revised strategy by Barry Warsaw
 """
+import unittest
 from test.test_support import verbose, import_module
 dl = import_module('dl', deprecated=True)