If you pump the gas line against the meter, even with the meter off, you run a risk of damaging the meter. Natural gas runs on very low pressure. 15 psi against the mechanisms of the meter can cause plenty of trouble. The method is to disconnect the pipe at the meter. Put the test gauge on there and pump it. (I always plug all ends of the gas lines too with plugs, not just gas cocks) In Washington, our test gauge must be of the 15 psi scale. (max of 15 psi) The test must hold for 10 minutes when the inspector arrives. I usually pump to 10 psi.
Remember that if you pump the line when the outside temperature is higher than when they do the inspection, the pressure will naturally be lower due expansion and contraction. I always beat the inspector to the jobsite on inspection day and pump the line to perfection about 20 minutes before his arrival.