There are better ways to do the test, but that's beside the point. Let's say that you have 10 different electronic devices and 10 different airplanes to test. That means that you have 100 different combinations to deal with. That is also over simplified because there are far more than 10 different electronic devices out there and far more than 10 different airplanes.

A far simpler approach would be to decide what limits airplanes must work within, then design airplanes around that. Then decide on what limits electronic devices must operate within, then design around that. Thing is, there are regulations around that but they aren't always followed. Or the electrical characteristics of a device changes over time, so what was true at the time of manufacturing isn't true anymore.

Engineering ain't simple. If it were, anybody could build a house in their back yard. But they can't do that, never mind design sophisticated aircraft or whiz-bang gadgets.