Jon, why do you need to test both ends? How can one end be correct and the other not?
You need to test both ends. Looks for opens, shorts, and wires connected to the wrong place.
Idea using less pins on the computer.
I have used a IC called "CD4017" to drive cables for testing. It is a ring counter. "reset" causes pin 0 to be high and pins 1-9 to be low. "Clock" causes the pins to go high one at a time (1,2,3,----9)
Because you need to drive 22 pins I would use 3 of the CD4017s. Connect all the resets together. I would not use "0" on the ICs. After reset all three "0"s will be high and all other pins are low. Toggle "Clock-1" ten time which will take one pin high at a time 1,2,3,4,5,6,7,8,9,0, (back to 0) Then toggle "Clock-2" ten times, then clock-3 ten times.
For the cost of 3 small ICs and 4 pins on the computer you have (9x3) pins that to high one at a time.
You can get the same effect with shift registers, in place of the ring counter. ( use very small computes with only 10 I/O pins)
The point is that test machines fail and it is better to replace small ICs that the entire computer. On the receiving end I could use a buffer IC or some thing to save the computer from static or over voltage on a input pin.