单元测试的好处之一是可预测性。

在单元测试之前，我可以非常准确地预测编写代码所需的时间，但无法预测调试所需的时间。

现在，因为我可以计划将要编写什么测试，所以我知道编码需要多长时间，并且在编码结束时，系统已经调试好了!这为开发过程带来了可预见性，消除了许多压力，但仍然保留了所有的乐趣!!

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。

在我们的办公室里，每天都有这样的对话:

“伙计，我就是喜欢单元测试，我刚刚能够对某些东西的工作方式进行了一系列更改，然后能够通过再次运行测试来确认我没有破坏任何东西……”

细节每天都在变化，但情绪却不变。单元测试和测试驱动开发(TDD)有很多隐藏的和个人的好处，也有很多明显的好处，除非他们自己做，否则你无法真正向他们解释。

但是，忽略这一点，下面是我的尝试!

Unit Tests allows you to make big changes to code quickly. You know it works now because you've run the tests, when you make the changes you need to make, you need to get the tests working again. This saves hours. TDD helps you to realise when to stop coding. Your tests give you confidence that you've done enough for now and can stop tweaking and move on to the next thing. The tests and the code work together to achieve better code. Your code could be bad / buggy. Your TEST could be bad / buggy. In TDD you are banking on the chances of both being bad / buggy being low. Often it's the test that needs fixing but that's still a good outcome. TDD helps with coding constipation. When faced with a large and daunting piece of work ahead writing the tests will get you moving quickly. Unit Tests help you really understand the design of the code you are working on. Instead of writing code to do something, you are starting by outlining all the conditions you are subjecting the code to and what outputs you'd expect from that. Unit Tests give you instant visual feedback, we all like the feeling of all those green lights when we've done. It's very satisfying. It's also much easier to pick up where you left off after an interruption because you can see where you got to - that next red light that needs fixing. Contrary to popular belief unit testing does not mean writing twice as much code, or coding slower. It's faster and more robust than coding without tests once you've got the hang of it. Test code itself is usually relatively trivial and doesn't add a big overhead to what you're doing. This is one you'll only believe when you're doing it :) I think it was Fowler who said: "Imperfect tests, run frequently, are much better than perfect tests that are never written at all". I interpret this as giving me permission to write tests where I think they'll be most useful even if the rest of my code coverage is woefully incomplete. Good unit tests can help document and define what something is supposed to do Unit tests help with code re-use. Migrate both your code and your tests to your new project. Tweak the code till the tests run again.

我参与的很多工作都没有很好地进行单元测试(web应用程序用户交互等)，但即使如此，我们在这个商店里都被测试感染了，当我们把测试束缚住时，我们最高兴。我怎么极力推荐这种方法都不为过。

关于这个话题，我写了一篇很大的博客文章。我发现单靠单元测试是不值得的，而且通常在截止日期临近时就会被削减。

与其从“测试后验证”的角度来讨论单元测试，我们应该看看在实现之前编写规范/测试/想法时所发现的真正价值。

这个简单的想法改变了我写软件的方式，我不会回到“旧的”方式。

测试优先开发如何改变了我的生活

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)。

关于单元测试要记住的一件事是，它对开发人员来说是一种安慰。

相反，功能测试是针对用户的:无论何时添加功能测试，您都是在测试用户将看到的东西。当您添加单元测试时，您只是让开发人员的生活更轻松。在这方面有点奢侈。

当您必须在编写单元或功能测试之间做出选择时，请记住这种二分法。