How do chinese manufacturer inspect air release valve?

How do chinese manufacturer inspect air release valve? This vedio to show you how do the pressure test for air release valve. air release valve,air relief valve,air release valve for water line,automatic air release valve,air compressor pressure relief valve,air compressor relief valve,quick release air valve,air release,air valve for water line,air pressure release valve,air release valve types,water air release valve,air relief valve for water line,irrigation air relief valve,air valve water main,irrigation air release valve,air valve for water tank,air release valve irrigation system,air valve release,wastewater air release valve,air valve manufacturers,water tank air release valve,air release valve manufacturers,water air relief valve,cast iron air release valve,water pump air release valve,water pipe air release valve,air release valve in water pipeline,air valve for water supply