Laptop keyboard bad or motherboard bad?

[David (PassMark)]

Assuming you have a clean O/S install and no malware, etc..

If one key doesn't work, then I think it is safe to assume it is the keyboard at fault.

If no keys work then it might be the keyboard or the motherboard. In this case swap the keyboard and see if the fault is fixed. If the fault is not fixed, then more likely it is the MB at fault.

I don't know if a hardware tester is practical as I can't imagine that all laptop keyboards are standard.

[axiomcrs]

Is there such a thing as a hardware tester (sw testers do not determine which part is bad) for laptop keyboards? Collecting every kb that exists is not practical. If no tester exists, then there must be a way to test the output of the kb.