I'm not arguing against tests as much as I'm suggesting that sufficient typing can provide a similar form of interactive refactoring that the author claims TDD

I'm not arguing against tests as much as I'm suggesting that sufficient typing can provide a similar form of interactive refactoring that the author claims TDD facilitates. Numerical functions are usually good candidates for tests. I don't even have an axe to grind about TDD itself. I don't do it and nobody forces me to. I'm just hypothesizing that the practice was tied to the primitive typing of its time. I could be wrong about this.