diff --git a/tests/fakedirstatewritetime.py b/tests/fakedirstatewritetime.py
--- a/tests/fakedirstatewritetime.py
+++ b/tests/fakedirstatewritetime.py
@@ -19,7 +19,7 @@
 configtable = {}
 configitem = registrar.configitem(configtable)
 
-configitem('fakedirstatewritetime', 'fakenow',
+configitem(b'fakedirstatewritetime', b'fakenow',
     default=None,
 )
 
@@ -39,7 +39,7 @@
 def fakewrite(ui, func):
     # fake "now" of 'pack_dirstate' only if it is invoked while 'func'
 
-    fakenow = ui.config('fakedirstatewritetime', 'fakenow')
+    fakenow = ui.config(b'fakedirstatewritetime', b'fakenow')
     if not fakenow:
         # Execute original one, if fakenow isn't configured. This is
         # useful to prevent subrepos from executing replaced one,
@@ -49,7 +49,7 @@
 
     # 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]
 
     orig_pack_dirstate = parsers.pack_dirstate
     orig_dirstate_getfsnow = dirstate._getfsnow