auth
auth/token_test.go
Let's test our verifyClient function. C'mon, it'll be fun! Add a function that tests the verifyClient function to our unit test suite. Basically, make sure that all the conceivable types of input have the right logic flow for what a "valid client" is. Also leave a note in client.go that makes it clear that public clients _should not be issued secrets in the first place_, because a public client that is issued a secret and specifies its client ID using the `client_id` POST body format will be told that it is not a valid client. While there are ways around this, the spec clearly states that non-confidential clients are not supposed to be issued secrets, so this seems like a nice way to conform to the spec or break trying.