Grant read rights

Hello

I try to grant read rights to a user but with no luck.

I execute this query:

GRANT Select ON test-db.* TO 'testuser'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION

I think the error occurs because I have a - in my db name.
I cannot rename the db as it is used in production.
Root user has no problem reading and writing to the test-db database.

Please advise

/Michael