connect a gas line to wherever your sending the gasoline to the
schrader valve on most modern fuel injected vehcles and turn key to
run, the pump in your gas tank will do what its designed to and pump
gasoline.

cost a length of neoprene hose and a schrader connector.

this is usually used to check fuel pump pressure at the vehicle
injectors. schrader valve is under hood

in a true end of the world as we know it you use a pan and slide it
under the vehicle and punch a hole in the tank.

hopefully no one will need that approach

one time my van would occasionally lose power, then be okk for days.

my mechanic connected a pressure gauge to my fuel line, the normal 100
pounds plus occasionally dropped to 15 pounds and my van stalled.....