Deleting the calendar named
/tasks/ is disallowed.
At least one additional calendar must exist (otherwise deletion is forbidden).
Everything else is super flaky. Creating a calendar works, but it is sometimes not available for a while (I've tested sleeping 10 seconds, but that's not enough).
Renaming a collection doesn't seem to have any effect.
Creating events in calendars doesn't seem to work; just an opaque 404.