"Unit tests are unlikely to test more than one trillionth of the functionality of any given method in a reasonable testing cycle. Get over it. (Trillion is not

"Unit tests are unlikely to test more than one trillionth of the functionality of any given method in a reasonable testing cycle. Get over it. (Trillion is not used rhetorically here, but is based on the different possible states given that the average object size is four words, and the conservative estimate that you are using 16-bit words)." It's the most bizarre reasoning I've seen for a while. Well, yes, of course, and my string trimming function will always have coverage of essentially 0% no matter what I do, since strings can be of any length, and there's way more possible strings than atoms in the universe... we clearly have a different concept of "functionality" though "When developers write code they insert about three system-affecting bugs per thousand lines of code. If we randomly seed my client’s code base — which includes the tests — with such bugs, we find that the tests will hold the code to an incorrect result more often than a genuine bug will cause the code to fail! Some people tell me that this doesn’t apply to them since they take more care in writing tests than in writing the original code. First, that’s just poppycock." Of course, because in reality it's not about being more careful or attentive. It's about the fact that tests don't (or aren't supposed to) contain any logic! (Meaning conditional statements of any sort, loops, etc.) It's logic that breeds an overwhelming majority of bugs. If your tests contain any, it means they're written badly. "even if it were true that the tests were higher quality than the code because of a better process or increased attentiveness, I would advise the team to improve their process so they take the smart pills when they write their code instead of when they write their tests" No, it's not about "smart pills" (this condescending tone is so annoying), it's about the fact that - otherwise than with my tests - I can't keep logic out of my production code. "Most programmers believe that source line coverage, or at least branch coverage, is enough. No. From the perspective of computing theory, worst-case coverage means investigating every possible combination of machine language sequences, ensuring that each instruction is reached..." ...oh God, enough. I don't know the author, but it's quite clear he's some CS professor rather than a real-life full time software dev Remember this article? http://blog.triplebyte.com/who-y-combinator-companies-want http://blog.triplebyte.com/who-y-combinator-companies-want https://phaven-prod.s3.amazonaws.com/files/image_part/asset/1669427/kXHIcd9WPsdYClR3CsnR9lipkDk/medium_who_yc_co_want.png https://phaven-prod.s3.amazonaws.com/files/image_part/asset/... - that's who YC startups want. When I saw it for the first time, I wondered why "academic programmers" rated the worst.