You don't need the pump in the engine to test it. Put inlet hose in can, outlet back to can and just move the arm up and down. If fuel spurts out the outlet the pump works. Make sure you have the correct pump as the arm rides against a cam like lobe to move it up and down.
If the pump works when out of the car but not when in the car, outlet hoses connected, probably a plugged or stuck float valve. Outlet hose not connected, probably wrong pump.