pwb.py wrapper is able to handle global args like -lang and -family settings. The doc says:
"""
python pwb.py <pwb options> <name_of_script> <options>
Currently <pwb options> are global options. This can be used for tests
to set the default site like (see T216825):
python pwb.py -lang:de bot_tests -v
"""But global option setting is ignored if running script_test.py because their own environment is executed with pwb_execute function