diff --git a/tests/fakepatchtime.py b/tests/fakepatchtime.py
--- a/tests/fakepatchtime.py
+++ b/tests/fakepatchtime.py
@@ -13,24 +13,24 @@ from mercurial import (
 configtable = {}
 configitem = registrar.configitem(configtable)
 
-configitem('fakepatchtime', 'fakenow',
+configitem(b'fakepatchtime', b'fakenow',
     default=None,
 )
 
 def internalpatch(orig, ui, repo, patchobj, strip,
-                  prefix='', files=None,
-                  eolmode='strict', similarity=0):
+                  prefix=b'', files=None,
+                  eolmode=b'strict', similarity=0):
     if files is None:
         files = set()
     r = orig(ui, repo, patchobj, strip,
              prefix=prefix, files=files,
              eolmode=eolmode, similarity=similarity)
 
-    fakenow = ui.config('fakepatchtime', 'fakenow')
+    fakenow = ui.config(b'fakepatchtime', b'fakenow')
     if fakenow:
         # parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
         # 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
-        fakenow = util.parsedate(fakenow, ['%Y%m%d%H%M'])[0]
+        fakenow = util.parsedate(fakenow, [b'%Y%m%d%H%M'])[0]
         for f in files:
             repo.wvfs.utime(f, (fakenow, fakenow))