diff --git a/python/re2_test.py b/python/re2_test.py
index 86aa9ae51..18b657db0 100644
--- a/python/re2_test.py
+++ b/python/re2_test.py
@@ -6,6 +6,7 @@
 import collections
 import pickle
 import re
+import os
 
 from absl.testing import absltest
 from absl.testing import parameterized