It is an error to attempt to delete INBOX or a
mailbox name that does not exist.
Test this and ensures this is the case (MPT tests for IMAP)
Ensure this to in JMAP.
Renaming INBOX is permitted, and has special behavior. It moves
all messages in INBOX to a new mailbox with the given name,
leaving INBOX empty. If the server implementation supports
inferior hierarchical names of INBOX, these are unaffected by a
rename of INBOX.
CF RFC-3501
Test this and ensures this is the case (MPT tests for IMAP)
Ensure this to in JMAP.
Also ensure this is tested. (MPT test)
Those behaviours shall also be true in JMAP.