How can I indicate that an IR LED is functioning without detecting its emissions?
Rig up a photosensitive resistor - they usually are sensitive far into the IR, and, as a bonus also into the UV. they have huge resistance without light, so you can use a battery without depleting it too fast. Another, normal resistor in series with that, to cap the maximum current to a few mA, and then an old school mA-indicator. Put the photoresistor at the end of a shiny (aluminium?) tube, and stick the LEDS you are testin into that (or, if they are SMD, put the tube over them, you'll have to isolate the tube then, though)