How to tell if a vintage Nikon camera flash works?

I just bought a box of random items at a sale and inside was a vintage 80s Nikon camera flash and lens. The flash is a Sunpak auto30DX Thyristror. I currently do not have a camera that this will work with. I put batteries in the compartment but was not able to get any of the lights to turn on and the ready/test button did not do anything. Does this flash need to be attached to a camera for it to work?

If it worked you would hear it charging with a high pitched whining noise… Also it should flash when you press the test button even if not on a camera… It is dead.

A flash unit should work by itself and the one you describe definitely would if it's good. Check that the batteries are correctly installed (there's usually a diagram on the inside of the battery compartment to help you insert them right). Take the trouble of cleaning the battery contacts; corrosion or grime is not always very visible. You may need a bit of steel wool or very fine sandpaper to help with this. When switched on, you should hear a whistling sound and after a few seconds the ready/test button should light up. When you depress it, the flash should fire. If none of this happens after you do everything else right, the unit is not working. Cheers.

If you put the batteries in the right way and they were charged then the flash is most likely dead.

The lens could be of interested though, depending on what it is it could even be expensive.