Author writes 'In order to be effective, a test needs to exist for some condition not handled by the code.' I think he is missing the point. In tests I write I

Author writes 'In order to be effective, a test needs to exist for some condition not handled by the code.' I think he is missing the point. In tests I write I capture what users do so I can gain some trust before releasing new code, that old still behaves the same way. I also often debug my new code by writing tests, especially on systems where I cannot just run my code against.