The output that the test expects is wrong. We get
./xkbcli: illegal option -- foobar
Usage: xkbcli [--help|-h] [--version|-V] <command> [<args>]
...
here. Thus, remove the wrong expectations to make the test pass.

--- libxkbcommon-xkbcommon-1.4.1/test/tool-option-parsing.py.orig	2022-05-21 21:55:22.000000000 +0000
+++ libxkbcommon-xkbcommon-1.4.1/test/tool-option-parsing.py	2022-11-13 11:02:58.556524894 +0000
@@ -111,8 +111,6 @@
     def run_command_unrecognized_option(self, args):
         rc, stdout, stderr = self.run_command(args)
         assert rc == 2, (rc, stdout, stderr)
-        assert stdout.startswith('Usage') or stdout == ''
-        assert 'unrecognized option' in stderr
 
     def run_command_missing_arg(self, args):
         rc, stdout, stderr = self.run_command(args)