diff --git a/Lib/test/test_json/test_scanstring.py b/Lib/test/test_json/test_scanstring.py
index cca556a3b95bab..9a6cdfe12d266c 100644
--- a/Lib/test/test_json/test_scanstring.py
+++ b/Lib/test/test_json/test_scanstring.py
@@ -144,7 +144,7 @@ def test_bad_escapes(self):
 
     def test_overflow(self):
         with self.assertRaises(OverflowError):
-            self.json.decoder.scanstring(b"xxx", sys.maxsize+1)
+            self.json.decoder.scanstring("xxx", sys.maxsize+1)
 
 
 class TestPyScanstring(TestScanstring, PyTest): pass