you can make a cyl adapter with an old spark plug and an air fitting.
bust the insulator out and remov ethe electrodes.. and then solder/braze/weld a male qd on it. perhaps an angle fitting first if planned to use on an N.. coud weld on a female threaded 90 and then just screw inthe male qd air adapter.. etc.
poor mans leak tester. then just about any air pump or air up tank will work for ya.,