Do they drug test you before you get your tonsils removed?

No. The only reason for drug tests are for employers to find out if they need to hire you, or for police to see if you're doing something that you shouldn't. The only reason for a hospital to test for it is to check for drug interactions with either the stuff they use to knock you out or for the pain meds that you get put on afterwords. For tonsils, you probably won't get pain meds though.