Since the SMART plugin is now implemented by using smartmontools it would be nice to include a timestamp of the last finished self test.
When I use smartctl -a /dev/sda to check status of my disk I can see a history of self-tests and it includes a LifeTime timestamp when the tests was finished. The LifeTime number corresponds to the disk power-on-hours value.
SMART Extended Self-test Log Version: 1 (1 sectors)
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 4539 -
# 2 Short offline Completed without error 00% 4372 -
# 3 Short offline Completed without error 00% 4132 -
...
It would be nice if this value was then available in the udisks dbus api.