diff --git a/Lib/test/test_tokenize.py b/Lib/test/test_tokenize.py
index 538612c..21eee6d 100644
--- a/Lib/test/test_tokenize.py
+++ b/Lib/test/test_tokenize.py
@@ -3,6 +3,7 @@
                      STRING, ENDMARKER, ENCODING, tok_name, detect_encoding,
                      open as tokenize_open, Untokenizer)
 from io import BytesIO
+import unittest
 from unittest import TestCase, mock
 from test.test_grammar import (VALID_UNDERSCORE_LITERALS,
                                INVALID_UNDERSCORE_LITERALS)