编写你的第一个 Django 程序 第5部分

测试将节省你的时间

到了一定程度，’检查代码是否运行正常’将是一个理想的测试。在更复杂的应用中，你可能有 几十个组件之间复杂的相互作用。

在这些组件中的任何修改对应用的行为都可能产生意想不到的后果。 检查应用仍然’似乎运行正常’可能意味着你的测试数据经过你的代码中二十多种变化功能后只是为了确保 你没有破坏它们 - 没有很好地利用你的时间。

特别是自动化测试可以在几秒中内为你做这件事。如果有什么地方出问题了，测试也将协助你找出 造成意外的代码。

Sometimes it may seem a chore to tear yourself away from your productive, creative programming work to face the unglamorous and unexciting business of writing tests, particularly when you know your code is working properly.

However, the task of writing tests is a lot more fulfilling than spending hours testing your application manually or trying to identify the cause of a newly-introduced problem.

Tests don’t just identify problems, they prevent them

It’s a mistake to think of tests merely as a negative aspect of development.

Without tests, the purpose or intended behavior of an application might be rather opaque. Even when it’s your own code, you will sometimes find yourself poking around in it trying to find out what exactly it’s doing.

Tests change that; they light up your code from the inside, and when something goes wrong, they focus light on the part that has gone wrong - even if you hadn’t even realized it had gone wrong.

Tests make your code more attractive

You might have created a brilliant piece of software, but you will find that many other developers will simply refuse to look at it because it lacks tests; without tests, they won’t trust it. Jacob Kaplan-Moss, one of Django’s original developers, says “Code without tests is broken by design.”

That other developers want to see tests in your software before they take it seriously is yet another reason for you to start writing tests.

Tests help teams work together

The previous points are written from the point of view of a single developer maintaining an application. Complex applications will be maintained by teams. Tests guarantee that colleagues don’t inadvertently break your code (and that you don’t break theirs without knowing). If you want to make a living as a Django programmer, you must be good at writing tests!