diff --git a/Lib/test/multibytecodec_support.py b/Lib/test/multibytecodec_support.py
index 5f08f106060..26bac7be108 100644
--- a/Lib/test/multibytecodec_support.py
+++ b/Lib/test/multibytecodec_support.py
@@ -108,6 +108,13 @@ class TestBase:
         self.assertEqual(self.encode(sin,
                                     "test.xmlcharnamereplace")[0], sout)
 
+    def test_callback_returns_bytes(self):
+        def myreplace(exc):
+            return (b"1234", exc.end)
+        codecs.register_error("test.cjktest", myreplace)
+        enc = self.encode("abc" + self.unmappedunicode + "def", "test.cjktest")[0]
+        self.assertEqual(enc, b"abc1234def")
+
     def test_callback_wrong_objects(self):
         def myreplace(exc):
             return (ret, exc.end)
diff --git a/Lib/test/test_multibytecodec.py b/Lib/test/test_multibytecodec.py
index 7b47cb50e82..feb7bd595a2 100644
--- a/Lib/test/test_multibytecodec.py
+++ b/Lib/test/test_multibytecodec.py
@@ -45,10 +45,6 @@ class Test_MultibyteCodec(unittest.TestCase):
         self.assertRaises(IndexError, dec,
                           b'apple\x92ham\x93spam', 'test.cjktest')
 
-    def test_errorhandler_returns_bytes(self):
-        enc = "\u30fb\udc80".encode('gb18030', 'surrogateescape')
-        self.assertEqual(enc, b'\x819\xa79\x80')
-
     def test_codingspec(self):
         try:
             for enc in ALL_CJKENCODINGS: