Test user account password reset

I have a couple of test accounts created more than year ago. Now these accounts have to be migrated to meta accounts, but to do that i have to login (with facebook), but don't know the passwords anymore. Have already tried a lot of passwords (giving up on that), working with app, ODH, etc. Password forgotten option also doesn't work because of of no access to (unknown) mailbox of the @tfbnw.net account.
Is there anyway to reset passwords of these accounts?
Or otherwise a simple migrate without logging in?