diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -5,6 +5,7 @@
 test-absorb-rename.t
 test-absorb-strip.t
 test-absorb.t
+test-acl.t
 test-add.t
 test-addremove-similar.t
 test-addremove.t
diff --git a/mercurial/posix.py b/mercurial/posix.py
--- a/mercurial/posix.py
+++ b/mercurial/posix.py
@@ -583,6 +583,7 @@
     """Return the list of members of the group with the given
     name, KeyError if the group does not exist.
     """
+    name = pycompat.sysstr(name)
     return list(grp.getgrnam(name).gr_mem)
 
 def spawndetached(args):