> Unit tests are a relatively recent concept (last 15-10 years?). I was writing unit tests 20 years ago. I generally see SUnit considered as the birth of unit

> Unit tests are a relatively recent concept (last 15-10 years?). I was writing unit tests 20 years ago. I generally see SUnit considered as the birth of unit testing frameworks, and that's 30 year old art to solve something that was being done before anyway. I guess one can say that Extreme Programming made it more popular in the mid 2000s, which is when relatively new languages started including built-in/standard unit testing libraries/frameworks/semantics (Python, Ruby, D...)