Have you talked with your HS counselor and/or testing coordinator to see if they can register as a test site?
If they can’t/won’t, ask you counselor to help find a site. You would have to contact counselors/testing coordinators at other HSs and ask them to host you. I would start with private and parochial schools. Also, if you can tap into the homeschool community they may be able to share some schools that are open to hosting you. Good luck.