Originally, the term “unit” in “unit test” referred not to the system under test but to the test itself. This implies that the test can be executed as one unit and does not rely on other tests running upfront (see here [1] and here [2]).
Via The big TDD misunderstanding (2022) | Hacker News [3], “The Big TDD Misunderstanding. 💡Originally, the term “unit” in “unit… | by Oliver Wolf | Mediu [4]” (also via Lobste.rs [5])
I think I finally have the answer to my question, “what is a ‘unit test?’ [6]” and … wow! And to think I was doing that all along at The Enterprise.
When I wrote the regression tests, I set each test up to be independent—each test got its own unique test data in the various “databases” we were using (we weren't really using a database, but custom binary data files based off a periodic database dump) and in theory, we could have run the tests in random order. In fact, during my last year there, I almost added that feature to the regression test, but by then, I was so burned out with The Process™ [7] that I just never bothered. It's a shame that, because I think it would have been an interesting form of test to perform.
[2] https://www.youtube.com/watch?v=HNjlJpuA5kQ
[3] https://news.ycombinator.com/item?id=38330989
[4] https://linkedrecords.com/the-big-tdd-misunderstanding-8e22c2f1fc21
[5] https://lobste.rs/s/clfulh/big_tdd_misunderstanding_2022