of course the real test is if it’s actually accurate at all those pressures – gauge accuracy usefully falls off significantly away from the middle of their range – so most HP pumps are good at road bike pressures but misread significantly at the 15-30psi of mountain bike tyres. 20psi on both my Lezyne and Silca is closer to 30.
Surely that assumes whatever you’re checking it with is accurate.
Either it’s the same range, same problems.
Or you use 2 separate gauges, and if one is inaccurate it just makes it look like the pump gauge is inaccurate at one end.
FWIW my Topeak pump, SKS guage and the old oxford guage all agree to within their stated accuracies.