Code Inspector wants a standing water test

[Kevin Branin]

I had the code inspector out to approve the rough work prior to closing the walls. He’s mandating my plumber to do a standing water test. Plumber has never done one before. The sanitary system needs to be filled all the way to the top fixture with water and let sit for 24 hours and inspected again. I’m thinking of getting the inflatable rubber bladder to plug up the lowest point on the stack and plugging the tub drain (tubs already installed), and all rough openings with a compressive / expanding rubber bung. Has anyone ever had to do this and offer advice or potential problems with my plan?