[Christ]

I didn't think of that... I suppose you could test this by... hm... how would you test for that... ok, i know!

What you need:
fuel pressure gauge.

Add the gauge inline with your fuel lines, after the fuel filter.
Disconnect both injectors, and the fuel pressure regulator, turn the key ON, but do not start the engine.
Turn the key to OFF after the fuel pump kicks off.
Immediately, after shutting the key off, check the fuel pressure displayed on the gauge... after a few seconds, check it again... if the injector(s) is/are leaking, the pressure will go down significantly, and quickly.