Fuel Pressure drop in traffic ???

TB
The volume test was just to prove the suction side was not restricted or collapsing. You will see it as the flow goes from full-flow at the test start, to almost zero-flow as the collapsed/collapsing hose shows up, or as a gradually reducing flow as the vent problem shows itself.Or some combination of suction-side issues.
But if it pumps a pint in 15 to 30 seconds, youve instantly proved its not a suction-side issue.But if it barely pumps anything out, then you have to figure out is it the pump or the line. And to the OP, no you dont rush out and buy a new pump. Its much easier to prove the line first.