使用 .env 文件进行单元测试

2022-01-16 00:00:00 unit-testing environment-variables javascript jestjs

是否可以从 env 文件加载环境变量以在 Jest 中进行单元测试?我希望像这样对其进行一系列测试:

Is it possible to load environment variables from an env file for unit testing purposes in Jest? I'm looking to run a series of tests on it like so:

// unit tests for env file
describe('env', () => {
    it('should have a client id', () => {
        expect(process.env.CLIENT_ID).toBeDefined();
    });
    it('should have a client secret', () => {
        expect(process.env.CLIENT_SECRET).toBeDefined();
    });
    it('should have a host', () => {
        expect(process.env.HOST).toBeDefined();
    });
    it('should have a scope', () => {
        expect(process.env.SCOPE).toBeDefined();
    });
    it('should have a response type', () => {
        expect(process.env.RESPONSE_TYPE).toBeDefined();
    });
    it('should have a redirect uri', () => {
        expect(process.env.REDIRECT_URI).toBeDefined();
    });
});

目前，上述所有测试都将失败，说明变量未定义.最初我使用的是 mocha/chai 设置，它允许我通过使用 dotenv 加载我的所有 env 变量.这涉及通过 webpack 运行所有单元测试并且工作正常.

Currently, all the above tests will fail, stating that the variables are undefined. Initially I was using a mocha/chai setup, which allowed me to just load all of my env variables via the use of dotenv. This involved running all unit tests through webpack and worked fine.

但是，通过阅读 文档 Jest 不会运行测试通过 webpack；相反，模块是通过 moduleNameMapper 模拟出来的.这适用于其他一切，但我无法加载 env 文件变量.到目前为止，我已经尝试将 setupFiles 选项用于调用 dotenv.config 的 js 文件，并使用给它的 env 文件的路径，如下所示:

However, from reading the documentation Jest doesn't run tests through webpack; instead modules are mocked out via moduleNameMapper. This works fine for everything else, but I can't get the env file variables to load. So far I've tried using the setupFiles option to a js file that calls dotenv.config with the path of the env file given to it like so:

// setup file for jest
const dotenv = require('dotenv');
dotenv.config({ path: './env' });

这不起作用，所以我现在只使用一个 .env.js 文件进行单元测试，并将这个文件传递给 setupFiles 选项.但是，为了可维护性，并使其与 webpack 一起用于生产，我想将它们全部保存在一个文件中.以下是 .env.js 文件如何查找以供参考的摘录

This didn't work, so I've now resorted to using just a .env.js file for unit tests and passing this file into the setupFiles option instead. However, for maintainability, and to keep it working with webpack for production, I'd like to just keep it all in one file. Here's an extract of how the .env.js file looks for reference 

// .env.js extract example
process.env.PORT = 3000;
process.env.HOST = 'localhost';
process.env.CLIENT_ID = 'your client id';
process.env.REDIRECT_URI = 'your callback endpoint';

推荐答案

您使用 ./ 的顶级配置路径从注入点来看是相对的，您的测试套件可能位于名为test 导致在运行单元测试时找不到它.dotenv.config(); 使用类似于绝对路径的全局注入策略.

Your top config path using ./ is relative from the point of injection, it's likely your test suite might be inside a folder named test which causes it to not be found when running your unit tests. dotenv.config(); Uses global injection strategy which is similar to absolute pathing.

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