Yes, that is the entire purpose of the load terminals of the GFCI. You can imagine that the protection element of the GFCI extends both to its receptacles, and then just imagine the load pair as another "receptacle".
As to the second part, yes, if you just connect the terminals together "before" the GFCI protection is in place, the GFCI will have no effect - remember, it can only sense problems on its own receptacles and its load terminals.
Grounded circuit (green/bare ground wire wired properly):
- Push "Test" on the GFCI protective device, and it trips -> PASS
- Push "Test" on the GFCI protective device, and it does not trip -> FAIL
- Push "Test" on a plug-in GFCI tester, and it trips -> PASS
- Push "Test" on a plug-in GFCI tester, and it does not trip -> FAIL
A fail here indicates the GFCI unit is probably defective.
Ungrounded circuit (green/bare absent or defective):
- Push "Test" on the GFCI protective device, and it trips -> PASS
- Push "Test" on the GFCI protective device, and it does not trip -> FAIL
- Push "Test" on a plug-in GFCI tester, and it trips -> FAIL FAIL FAIL
- Push "Test" on a plug-in GFCI tester at the GFCI receptacle, and it does not trip -> PASS
- Push "Test" on a plug-in GFCI tester at a downstream protected outlet, and it does not trip -> MEANINGLESS
Fail at the GFCI device probably indicates it is defective.
Fail on the plug-in GFCI tester (i.e. it trips!) indicates they have bootlegged ground at the GFCI receptacle- attached the neutral wire to both neutral and ground. It will seem to work at the GFCI, but is still dangerous.
Bootlegging ground at a downstream GFCI receptacle is a mistake, because one of several electrical faults could put 120V on the the grounds, e.g. the cover plate screws or a machine chassis. However this is difficult to detect, since a properly wired downstream receptacle will behave exactly the same way. This means for ungrounded downstream receptacles, plug-in tester testing is completely meaningless.
Once you have settled the question of bootlegged grounds, here's how you test an ungrounded GFCI. Plug your GFCI tester into your handy dandy 2-3 prong "cheater" - the kind with a short green wire as a pigtail. Extend that green wire all the way to a reliable ground source, e.g. the panel in the basement. Now, the GFCI tester should work normally, since you have rigged a proper ground to it.
GFCI protection is pretty effective, and I would be confident in an ungrounded circuit if it has GFCI protection. However if you are unable to get the external device to trip, you'll need to pop the cover off and see if the ground is present, missing or bootlegged.
Best Answer
Just get a GFCI tester for $8. It allows you to quickly test outlets to see if they’re properly wired and allow you to test the GFCI itself through the test button. Inexpensive insurance for the whole house.