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
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Answer
You can use jest.resetModules()
in beforeEach
method to reset the already required modules
beforeEach(() => { jest.resetModules() process.env = { ...OLD_ENV }; delete process.env.NODE_ENV; });