Restored database is missing user

I have a SharePoint content database that has been restored into our test environment. I am getting errors in the SQL log indicating our SharePoint service account is not able to access the database. SVC.Sharepoint exists as a login at the server instance level and is the db_owner for the database. However, when I check sys.database_principals it doesn't appear in the list. When I look at all of the articles and blogs regarding this I'm told it is an orphaned users problem. But isn't an orphaned user when you have the user but no login? I appear to have the opposite problem where the login exists with no matching database user. How can I fix this?