#Unit and benchmark tests unit test a code

Code coverage is a measurable approximation of immeasurable qualities we care about. Does it prove correctness? Not at all, but it has a clear relationship to how well-tested the code is, which in turn is our best way to increase confidence in its correctness. Those debates are useful and should occur, but they also expose uncertainty.Ĭode coverage is an objective measurement: Once you see your coverage report, there is no ambiguity about whether standards have been met are useful. This is more knowable, but is still a subjective standard: It will always be open to debate whether or not you have met it. For most software, we can't possibly know this across all inputs, so we settle for saying that code is well-tested. What do I mean by 'empirical confidence'? Well, the real goal correctness. When to set code coverage requirementsįirst, why would you want to impose such a standard in the first place? In general, when you want to introduce empirical confidence in your process. I am not an expert in test engineering and would be happy to see a more informed answer. Where the accepted answer falls short, in my opinion, is in describing how one might make that decision for a given project. There are projects that just don't need such a standard. Jon Limjap makes a good point - there is not a single number that is going to make sense as a standard for every project. “The third programmer wants only simple answers – even when there are “The second programmer, on the other hand, is quite experience both “The first programmer is new and just getting started with testing. “Come get some fresh tea with me and let’s talk about it.”

“Great master, today I overheard you answer the same question about “Eighty percent and no less!” Replied the master in a stern voice, “How can I possibly tell you? It depends on how many people you need to “How many grains of rice should I put in that pot?” “Don’t worry about coverage, just write some good tests.” This prose by Alberto Savoia answers precisely that question (in a nicely entertaining manner at that!):