Unit Testing is one of the most adopted methodologies for high quality code. Its contribution to a more stable, independent and documented code is well proven . Unit test code is considered and handled as an a integral part of your repository, and as such requires development and maintenance. However, developers often encounter a situation where the resources invested in unit tests where not as fruitful as one would expect. In an ideal world every method we code will have a series of tests covering it’s code and validating it’s correctness. However, usually due to time limitations we either skip some tests or write poor quality ones. In such reality, while keeping in mind the amount of resources invested in unit testing development and maintenance, one must ask himself, given the available time, which code deserve testing the most? And from the existing tests, which tests are actually worth keeping and maintaining? See here

当您手动测试软件时，通常会使用一小组测试/操作。最终，您将自动修改输入数据或操作，以便围绕已知问题进行导航。应该有单元测试来提醒您某些事情不能正常工作。

我建议在编写代码之前编写测试，添加新的测试/数据来改进主代码的功能!

单元测试的全部意义在于使测试变得简单。这是自动的。“make test”就完成了。如果您面临的问题之一是难以测试代码，那么这就是使用单元测试的最佳理由。

还没有人提到的一件事是，让所有开发人员承诺实际运行和更新任何现有的自动化测试。当您重新进行自动化测试并发现由于新的开发而出现故障时，会失去很多价值并使自动化测试非常痛苦。因为开发人员已经手动测试了代码，所以大多数测试不会指出错误，所以花在更新它们上的时间只是浪费。

说服怀疑者不要破坏其他人在单元测试上所做的工作，对于从测试中获得价值更为重要，而且可能更容易。

每次从存储库更新时，花费数小时更新由于新特性而损坏的测试既没有效率也没有乐趣。

我同意与大多数人相反的观点: 不编写单元测试是可以的 特别是重原型的编程(例如AI)很难与单元测试相结合。

One of the best things about unit testing is that your code will become easier to test as you do it. Preexisting code created without tests is always a challenge because since they weren't meant to be unit-tested, it's not rare to have a high level of coupling between classes, hard-to-configure objects inside your class - like an e-mail sending service reference - and so on. But don't let this bring you down! You'll see that your overall code design will become better as you start to write unit-tests, and the more you test, the more confident you'll become on making even more changes to it without fear of breaking you application or introducing bugs.

There are several reasons to unit-test your code, but as time progresses, you'll find out that the time you save on testing is one of the best reasons to do it. In a system I've just delivered, I insisted on doing automated unit-testing in spite of the claims that I'd spend way more time doing the tests than I would by testing the system manually. With all my unit tests done, I run more than 400 test cases in less than 10 minutes, and every time I had to do a small change in the code, all it took me to be sure the code was still working without bugs was ten minutes. Can you imagine the time one would spend to run those 400+ test cases by hand?

当涉及到自动化测试——无论是单元测试还是验收测试——每个人都认为编写可以手动完成的代码是浪费精力，有时这是真的——如果你计划只运行一次测试的话。自动化测试最好的部分是，您可以毫不费力地运行它们几次，并且在第二次或第三次运行之后，您所浪费的时间和精力已经得到了补偿。

最后一个建议是，不仅要对代码进行单元测试，还要先进行测试(详见TDD和BDD)。