I think this is a good idea. There's always a tradeoff where there is some value in testing against the actual backend vs having a mock + a separate imap backend test. But I think especially we the currently relatively simple interface having a mock makes a lot of sense to make our tests faster and more robust.

I'm going to keep tests against a real backend in tests/Feature/Backends/, where all IMAP methods should have it's test. Also DataMigrator tests and Infrastructure tests will stay this way.

But anywhere else we can use mocking.

In D5202#66198, @machniak wrote:

I'm going to keep tests against a real backend in tests/Feature/Backends/, where all IMAP methods should have it's test. Also DataMigrator tests and Infrastructure tests will stay this way.

But anywhere else we can use mocking.

Sounds good. I was just making a general point, your plan sounds great.

This is now completed for LDAP and IMAP facades and ready for review. There were some more tricks needed, but I like the result. These changes already revealed two small bugs that I fixed.