If there are NO joints in the trench, no test is required. However , the inspector does need to see the open trench with pipe therein. Only black pipe or other approved material is allowed for the interior gas piping. No gas piping shall be buried under any structure. It is not allowed in or under any exterior slab, unless, it is sleeved and prior approval has been given for such installation.
All appliances are to be installed per the manufacturer's listed requirements.
No LP appliances are allowed in a basement, crawlspace, pit, bathroom, or bedroom, and are not to be accessed through a bathroom or bedroom.