2000, 2003, 2006, & 2009 IRC, P2503.5.1 Rough Plumbing.
Test required for PVC DWV system.
"DWV systems shall be tested on completion of the rough piping installation by water; or (if not plastic, PVC) by air; with no evidence of leakage. Either test shall be applied to the drainage system in it's entirety or in sections after rough piping has been installed as follows:
Water test. Each section shall be filled with water to a point not less than 10 feet above the highest fitting connection in that section. or to the hightest point in the completed system."
In other words; the entire DWV system including the vent system must be filled with water to a height, not less than 10 feet above the highest fitting or to the top of the highest vent above the roof.
I have noticed over the years that this test has been omitted in most jurisdictions I have visited.
NOTE: This is not the Building sewer test of the underground system. This is after the drain waste and vent system (DWV) has been completed (including the vent through the roof).
Are you and/or your AHJ requiring and inspecting this test on residential construction?