diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -316,6 +316,7 @@ test-log-exthook.t
 test-log-linerange.t
 test-log.t
 test-logexchange.t
+test-logtoprocess.t
 test-lrucachedict.py
 test-mactext.t
 test-mailmap.t
diff --git a/tests/test-logtoprocess.t b/tests/test-logtoprocess.t
--- a/tests/test-logtoprocess.t
+++ b/tests/test-logtoprocess.t
@@ -14,12 +14,12 @@ Test if logtoprocess correctly captures 
   > command = registrar.command(cmdtable)
   > configtable = {}
   > configitem = registrar.configitem(configtable)
-  > configitem('logtoprocess', 'foo',
+  > configitem(b'logtoprocess', b'foo',
   >     default=None,
   > )
   > @command(b'foobar', [])
   > def foo(ui, repo):
-  >     ui.log('foo', 'a message: %s\n', 'spam')
+  >     ui.log(b'foo', b'a message: %s\n', b'spam')
   > EOF
   $ cp $HGRCPATH $HGRCPATH.bak
   $ cat >> $HGRCPATH << EOF