I needed an SMD LED tester for my ongoing project. Unfortunately the local parts store puts everything into a single paper bag without designation, so I wasn't able to distinguish between the red and the blue 0603 LEDs.
A Kelvin clip from eBay, two banana plugs, a 330 ohm resistor, some loudspeaker wire, and lots of heatshrink.
The resistor in the wire:
The finished "instrument":
First I thought that the shorter heatshrink on the clip's leg will designate the positive lead but later realized that it would be a great idea to put heatshrink onto the tips and in this small size I had red one also.