no, i am speaking quite precisely. 01923 is hardly medieval, and that's when the term came into common use in engineering jargon, with pretty much its current meaning, plus or minus about ten years

https://books.google.com/ngrams/graph?content=unit+tests&yea...

This is a little off, unless you give “unit” a very different term than most use it. The term unit vs division tests are used in the military, so a unit test is to check combat readiness of a unit and division tests is the combat readiness of a division. The books that use that term mostly come from US Artillery documentation.

I wonder if the etymology of modern unit testing does come from that; but if it did I’d assume the other terms would exist too.

interesting, i appreciate the correction. for some reason the google books date range searches linked from the n-grams page weren't loading for me, and the corresponding internet archive searches are also broken

there also seem to be some search hits from 'unit tests' for education, in which the 'unit' is presumably a course or subdivision thereof; https://www.google.com.ar/books/edition/The_Organization_of_... is an example, though sadly google refuses to show me any excerpts, perhaps because i'm in a country they don't like

https://www.google.com.ar/books/edition/Naval_Training_Bulle... does show an excerpt

so i guess the engineering use might date from later, perhaps as late as the 01960s

Sorry, by "pre-modern" I just meant "before the computer era"

oh, yeah, probably before the computer era, though see the other comment thread for a possible shortening of the time frame; "unit test" in the engineering sense might date from as recently as the 01960s