before SPAM, when Trojan meant birth-control and a virus was probably Herpes, or AIDS, and not something that could render your computer useless.

Back then, when the "popular" PIC was the PIC16C54 or thereabouts, virtually everyone who had an interest built up a circuit that transmitted serial data to an LCD. Most of them only did half the job, of course, in that they didn't monitor the busy flag, choosing instead to wait out the worst case delay for completion of any command. That ruled out a number of intrinsic functions.

A "real" tester would verify that every function in the device works as specified, including the unused data memory locations, the character generator ram, etc. and that it scrolled, blinked, and placed characters in every mode described in the datasheet. AFAIK, the 8748 version I loaned to a colleague is the only one I've encountered that does all that.

RE