DWV Line Testing Device - Can I make one?

I would like to pressure test my DWV line since I just added a new toilet line and extended the pipe on another toilet. Can I make the device needed to pressure test the line? I read somewhere you could rent them but I'm not finding any. Any other ideas on testing the line? Thanks.

You have to have all inlets and outlets capped. You can glue a cap on one end with an air fitting and gauge. fill it to the desired pressure and wait. Cut it off when done.

What's risk of not doing the pressure test? I can run a garden hose into the line let it run for 10 minutes. But, that won't really test the vent lines to the ceiling that I also changed. I'm not too concerened about leaks as I took my time and really coated the ABS pipes with cement but reading all the Plumbing Code books has me paranoid about not doing every little thing.....