I have a file with object that gets populated with process.env properties:

env.js

console.log('LOADING env.js');



const {

  PROXY_PREFIX = '/api/',

  USE_PROXY = 'true',

  APP_PORT = '8080',

  API_URL = 'https://api.address.com/',

  NODE_ENV = 'production',

} = process.env;



const ENV = {

  PROXY_PREFIX,

  USE_PROXY,

  APP_PORT,

  API_URL,

  NODE_ENV,

};



module.exports.ENV = ENV;

Now I try to test this file with different process.env properties:

env.test.js

const envFilePath = '../../config/env';



describe('environmental variables', () => {

  const OLD_ENV = process.env;



  beforeEach(() => {

    process.env = { ...OLD_ENV };

    delete process.env.NODE_ENV;

  });



  afterEach(() => {

    process.env = OLD_ENV;

  });



  test('have default values', () => {

    const { ENV } = require(envFilePath);

    expect(ENV).toMatchSnapshot();

  });



  test('are string values (to avoid casting errors)', () => {

    const { ENV } = require(envFilePath);

    Object.values(ENV).forEach(val => expect(typeof val).toEqual('string'));

  });



  test('will receive process.env variables', () => {

    process.env.NODE_ENV = 'dev';

    process.env.PROXY_PREFIX = '/new-prefix/';

    process.env.API_URL = 'https://new-api.com/';

    process.env.APP_PORT = '7080';

    process.env.USE_PROXY = 'false';



    const { ENV } = require(envFilePath);



    expect(ENV.NODE_ENV).toEqual('dev');

    expect(ENV.PROXY_PREFIX).toEqual('/new-prefix/');

    expect(ENV.API_URL).toEqual('https://new-api.com/');

    expect(ENV.APP_PORT).toEqual('7080');

    expect(ENV.USE_PROXY).toEqual('false');

  });

});

Unfortunately, even though I try to load the file in every test separately the file gets loaded only once, making the third test fail with:

Expected value to equal:

  dev

Received:

  production

P.S. It doesn't fail when I run the test alone.

I also know that env.js loads only once because console.log('LOADING env.js'); gets fired only once.

I tried to invalidate Nodes cache like:

  beforeEach(() => {

    delete require.cache[require.resolve(envFilePath)];

    process.env = { ...OLD_ENV };

    delete process.env.NODE_ENV;

  });

but require.cache is empty {} before each test so it seems that Jest is somehow responsible for importing the file.

I also tried to run yarn jest --no-cache but didn't help.

So what I want is to load env.js before each test so I can test how it behaves with different node environmental variables.

jest@^22.0.4