Done via CalDAV. Running backend tests (no syncing):

CLIENT_TEST_SIMPLE_UID=1 \
CLIENT_TEST_UNIQUE_UID=1 \
CLIENT_TEST_SERVER=google \
"CLIENT_TEST_WEBDAV=google caldav testcases=testcases/google_event.ics" \
./client-test Client::Source

"simple UID" needed because special characters like % confuse the server.
"unique ID" works around issues with unintentionally restoring older
revisions of the test cases (?).

google_event.ics is derived from eds_event.ics and was modified to
avoid test breakage because of the following changes seen in
testImport (all caused by the server):

* EST/DST timezone mapped to America/New_York, despite not having quite
  the same transition rules
* all recurring events must have a time zone, UTC is not supported
  (but correctly converted into time zone of calendar)
* BYMONTHDAY=6 is added in a sitatution were it is redundant
  (can be inferred from day of recurring event)
* UNTIL clause turned into UTC
* "DESCRIPTION:This is an event reminder" added to VALARM
* CN property is replaced with lower case email
* email address all lower case
* ATTENDEE RSVP not supported
* X-NUM-GUESTS added to ATTENDEE

Changes dealt with in synccompare:
* calendar owner is added as ATTENDEE to meetings, regardless whether it
  was meant to attend
