How to test tzdist in Cassandane?

[rsto at paranoia.at]

Hi,

I am currently implementing the JMAP calendar event handlers and have a
hard time testing them in Cassandane in combination with timezone
references. 

In my experimental JMAP-enabled httpd, I translate a newly created JMAP
calendar event to iCalendar and store it by use of caldav_store_resource
(http_caldav.c). This currently works, as long as I store the VTIMEZONE
components along with the VEVENT, but it wastes a lot of space.
caldav_store_resource only seems to remove these redundant VTIMEZONEs
from the enclosing VCALENDAR, if tzdist is enabled in the httpmodules.

I know how to use vzic to generate the zoneinfo dabatase, as well as how
to enable tzdist in Cassandane's http modules. However, I can't figure
out, how to make Cassandane use a custom zoneinfo.db and the auto
generated one is only about 336 bytes (as opposed to a full-blown
zoneinfo database generated from the latest Olsen database).

Is there any hook in Cassandane where I can populate the temporary
configdir, once it has been generated but before tests are run?

Thanks a lot,
Robert