diff --git a/Lib/test/test_genericpath.py b/Lib/test/test_genericpath.py
index d7644e8ef45..b77d1d79a1e 100644
--- a/Lib/test/test_genericpath.py
+++ b/Lib/test/test_genericpath.py
@@ -282,7 +282,7 @@ def test_null_bytes(self):
             with self.subTest(attr=attr):
                 with self.assertRaises(ValueError) as cm:
                     getattr(self.pathmodule, attr)('/tmp\x00abcds')
-                self.assertEqual(str(cm.exception), 'embedded null byte')
+                self.assertIn('embedded null', str(cm.exception))
 
 # Following TestCase is not supposed to be run from test_genericpath.
 # It is inherited by other test modules (macpath, ntpath, posixpath).