diff --git a/pandas/tests/test_strings.py b/pandas/tests/test_strings.py
index d49338af698d1..d057dc5304277 100644
--- a/pandas/tests/test_strings.py
+++ b/pandas/tests/test_strings.py
@@ -350,8 +350,8 @@ def test_replace(self):
         tm.assert_series_equal(result, exp)
 
         #flags + unicode
-        values = Series(["abcd,\xc3\xa0".decode("utf-8")])
-        exp = Series(["abcd, \xc3\xa0".decode("utf-8")])
+        values = Series([b"abcd,\xc3\xa0".decode("utf-8")])
+        exp = Series([b"abcd, \xc3\xa0".decode("utf-8")])
         result = values.str.replace("(?<=\w),(?=\w)", ", ", flags=re.UNICODE)
         tm.assert_series_equal(result, exp)