Here's a more useful test.
write a simple script that creates a 100 or so dbs. Run it against
each database, and while it's running, pull the power plug. Plug back
in, see if your database comes back up uncorrupted.
If pgsql is on proper db hardware (i.e. it obeys fsync, has battery
backed cache on a RAID controller, etc) it should come up no problems.
Since the system catalogs are stored in the same transactional engine
/ table type as everything else. On MySQL, maybe, maybe not, as the
system catalogs are always stored in MyISAM tables even if you dont'
use them for anything else.