diff --git a/tests/test-blackbox.t b/tests/test-blackbox.t
--- a/tests/test-blackbox.t
+++ b/tests/test-blackbox.t
@@ -390,7 +390,7 @@
   > from mercurial import registrar, scmutil
   > cmdtable = {}
   > command = registrar.command(cmdtable)
-  > @command('noop')
+  > @command(b'noop')
   > def noop(ui, repo):
   >     pass
   > EOF