I cooped at IBM in the 1980s and this is how we tested and verified the newest IBM PC hardware (at this point IIRC it would have been around the 286/pc junior/o

I cooped at IBM in the 1980s and this is how we tested and verified the newest IBM PC hardware (at this point IIRC it would have been around the 286/pc junior/os2/smaller form factor ibm pc designs) by creating tests on current systems with manual keyboard entry, and recording all the key strokes/timing and screen buffers and output files at intervals then running the same tests on new hardware with a playback of recorded input and comparing the new output to the saved runs.