Actually, you can test the accumulator by just removing the bleed hose from the backside (clamp it shut or fuel will run out it from the opposite direction).
Let the collected fuel run out of the accumulator, there should not be very much. Then crank the engine or turn on the ignition a couple times to charge the fuel system, and look for more drippage out the accumulator. If it does drip, the diaphragm is cracked and it's toast.
Of course, guages are much more elegant. Hook up the pressure gauge to the fuel inlet line at the fuel distributor and turn the ignition on ONCE. Pressure should zoom to 100 or above, and should hold quite high for some time. Best way to check everything ,though, is to hook the gauge to the plug in the upper chamber of the distributor, and then hit the ignition switch a couple times to run the pump. Pressure should jump to about 80, then drop off to below 50 when the pump stops. Should hold around 40 for some time, at least 30 minutes or so. If it drops pretty quick, then it's the accumulator, the check valve at the pump, injectors, or regulator.

Only way I remember all this is I checked mine Saturday.

DG