Comment by 9rx

Definitely not. The Art of Software Testing wrote about "module testing" in 1979, which was revised as "unit testing" in a later revision after "unit test" was part of the popular lexicon. Perhaps that is what you are thinking of?

Beck is clear that he "rediscovered" the idea. People most certainly understood the importance of tests being isolated from each other in the 1960s. Is that, maybe, what you mean?