防止“测试/期望/等未定义”使用Jest时出错 [英] Prevent "test/expect/etc is not defined" errors when using Jest

问题描述

Facebook的Jest测试框架很容易

类似，尝试直接使用 node 运行测试文件将失败并显示 ReferenceError：test未定义。

需要 / import 需要为那些语句添加语句错误消失？

解决方案

节点

如果要直接通过节点运行它们，请尝试要求 jest 和/或 jest-runtime 。同时给出 @ types / jest 尝试一下。

检查编辑2以获取有关此内容的新信息

编辑

@ types / jest （ jest-DefinitelyTyped ）绝对需要（或只是一个解决方案）。如果您安装（例如，dev依赖项），则IDE错误应该消失。
我刚刚在Webstorm上试过它，它可以工作。

编辑2

新的 Jest @ 20 Matchers （例如， .resolves 和 .rejects ）仍未在 @ types / jest 中定义。您可以在以下链接中跟踪其状态：
https://github.com / DefinitelyTyped / DefinitelyTyped / pull / 16645
https://github.com / DefinitelyTyped / DefinitelyTyped / issues / 16803

尽管如此，它应该可用！

此外，似乎无法直接通过节点运行它。昨晚我尝试了很多不同的东西，但是使用jest是要走的路 - 它确实使用了引擎盖下的节点，所以我认为它也是可能的。 @thymikee 对你在GitHub上发布的问题明确表示不是。

编辑3

新版本（ 20.0.1 ）包含最新的Jest定义。

Lint

这不在这个特定问题的范围内，但它也有帮助

您使用的是 ESLint 吗？如果是这样，你需要 eslint-plugin-jest

按照本页描述的步骤： https://www.npmjs.com/package/eslint-plugin-jest ，你基本上需要将它添加为ESLint插件并在ESLint配置中设置jest globals：

  {
env ：{
jest / globals：true 
} 
} 
  

如果您打算支持 ES6测试，您还需要 Babel 和 babel-jest 具有以下jest配置的插件：

 transform：{
^。+ \ \ .js $：babel-jest
} 
  

最后，对于 Typescript 测试你需要 @ types / jest 和 ts-jest 包

Facebook's Jest testing framework is easy to get started with, but the documentation overlooks an annoying aspect: test statements will be highlighted as errors by any editor that tries to warn of undefined symbols, because test, expect, and all matcher methods are not defined.

Similary, attempting to run a test file with node directly will fail with ReferenceError: test is not defined.

What require/import statement(s) need to be added for those errors to go away?

解决方案

Node

If you want to run them directly through node, try to require jest and/or jest-runtime. Also give @types/jest a try as well.

Check Edit 2 for new info about this

Edit

@types/jest (jest-DefinitelyTyped) is definitely needed (or just one solution). If you install it (e.g., dev dependency), the IDE errors should go away. I just tried it on Webstorm, and it works.

Edit 2

The new Jest@20 Matchers (e.g., .resolves and .rejects) are still not defined in @types/jest. You can keep track of its status on the links below: https://github.com/DefinitelyTyped/DefinitelyTyped/pull/16645 https://github.com/DefinitelyTyped/DefinitelyTyped/issues/16803

It should be available soon, though!

Also, it doesn't seem possible to run it directly through node. Last night I tried a bunch of different things, but using jest is the way to go - it really uses node under the hood, so I thought it would be possible as well. @thymikee over your opened issue at GitHub made clear that it's not.

Edit 3

The new release (20.0.1) includes the newest Jest definitions.

Lint

this isn't in the scope of this specific problem, but it also helps

Are you using something like ESLint? If so, you'll need eslint-plugin-jest

Following the steps described in this page: https://www.npmjs.com/package/eslint-plugin-jest, you will basically need to add it as an ESLint plugin and set jest globals in the ESLint configuration:

{
  "env": {
    "jest/globals": true
  }
}

If you plan on supporting ES6 tests, you'll also need Babel and babel-jest plugin with the following jest configuration:

"transform": {
  "^.+\\.js$": "babel-jest"
}

Finally, for Typescript tests you'd need the @types/jest and ts-jest packages as well

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