如何确定JEST是否正在运行代码？ [英] How to determine if JEST is running the code or not?

问题描述

我正在我的react-native项目上创建一个JS测试。我特意使用firebase for react native，如果JS正在运行我的类的代码，我想用mockfirebase实例替换firebase实例。

I am creating a JS test on my react-native project. I'm specifically using firebase for react native, in which I would like to replace firebase instance with a mockfirebase instance if JS is running the code of my class.

例如我有类似下面的课程设置。

For example I have class setup like below.

import firebase from 'react-native-firebase';
class Database() {
    /// use the firebase instance
}

我想检查jest是否是运行环境然后我用适当的模拟类替换导入行。

I'd like to have a check if jest is the running environment then I'd replace the import line with appropriate mock class.

推荐答案

jest设置一个名为JEST_WORKER_ID的环境变量，以便检查是否已设置：

jest sets an environment variable called JEST_WORKER_ID so you check if this is set:

function areWeTestingWithJest() {
    return process.env.JEST_WORKER_ID !== undefined;
}

我还看到如果未设置NODE_ENV，则jest CLI将其设置为价值'测试'。这可能是另一种检查方式。

I also see that if NODE_ENV is not set the jest CLI sets it to the value 'test'. This might be another way to check.

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