Is there a test to figure out if you have glaucoma?

Not just ONE test...: Diagnosis of glaucoma is optimally made before a patient notices any vision loss. Eye pressure, visual field (peripheral vision), optic nerve health, corneal thickness, fam history, patient history (medications, eg migraines etc) are evaluated to assess the risk in a given eye/patient. There is no one test that can say yes/no re glaucoma, unless the visual field has classic damage (late by then.

Yes: Visual field, optic nerve evaluation (photos, oct), pressure check. Typically need several checks to determine progression to confirm active glaucomatous loss.