What is the best way to air pressure test a new pvc waste/vent line?

The plumbing inspector wants it air tested @ 5 psi for 15 minutes. This is the rough plumbing for a second floor addition, so I've glued all the pvc, but have not glued the connections to the main soil stack or to the main vent stack.

Can I simply cover all the open connections with fernco quickcaps and use one opening for the gauge and air injection? For the gauge fitting, can I just concoct something temporarily that will go from 1 1/2" (for the sink) to a 1/2" thread so I can connect my gauage (which also has an air inlet and stop valve)?

The gauge I have is 0-100 psi, so that probably isn't accurate enough for 5 psi is it?

Is there more to this?

I don't think it matters how you plug up the ends. When I roughed-in a recent bathroom addition, I used a toilet flange with a knockout seal, and put test plugs in the shower and vent through the roof. Then I used a Fernco coupling to a PVC 1-1/2" to 1/2" fitting to connect the 1/2" pipe that went to my gauge, ball valve, and air fitting.

I also put a test tee right before I wyed into the main drain. This way I could use a test ball to isolate the new branch from my existing drains.

My inspector seemed to like this setup. One thing though, In my area the gauge couldn't be more than 15psi full-scale. They are a little hard to find but I found one online.

Hi Steve,

In our area we use a water static test for our rough ins. We seal off all the openings and place a inflatable test ball in the clean out to completely seal it off, fill the stacks from the roof and let it set overnight. Next day the inspector shows up and if there's still water in the stacks, and no leaks, the job gets passed.

"Can I simply cover all the open connections with fernco quickcaps and use one opening for the gauge and air injection? For the gauge fitting, can I just concoct something temporarily that will go from 1 1/2" (for the sink) to a 1/2" thread so I can connect my gauage (which also has an air inlet and stop valve)?"
Yes, you can bush down the 1 1/2" opening to 1/2", (most gages are 1/4" male threads.)
"The gauge I have is 0-100 psi, so that probably isn't accurate enough for 5 psi is it?"
The inspector will probably need a more accurate gage then 100 PSI.

"Is there more to this?"

You seem to have covered all bases. Good luck on the inspection, Tom