Which is the outlet test port on this valve (VR8204A)
Looks to me like the test access port is located right where indicated in the picture below.



Note that the pressure meter is often also used to check for leaks after gas pipe and control valve installation. The meter unit would be attached. Then the gas supply turned on to pressurize the line. The meter will show a reading based on the line pressure. Then the source gas valve and all gas consumers on the line are left in their OFF state for 24 to 48 hours. If during that long period of time there is any noted movement of the needle on the meter then it is known there is a leak in the gas supply someplace that needs attention and correction.