Easy way to mock process.env during BDD testing
Read Mocking process.env blog post.
Requires Node version 6 or above.
npm install --save-dev mocked-envconst mockedEnv = require('mocked-env')
// before the test
let restore = mockedEnv({
FOO: 'fake foo value',
BAR: '42',
})
// use process.env.FOO and process.env.BAR during testing
// process.env.FOO = "fake foo value"
// process.env.BAR = "42"
// after the test
restore()
// any previous values of FOO and BAR restoredIf you want to temporarily delete environment variable, pass undefined value
let restore = mockedEnv({
FOO: 'fake foo value',
PWD: undefined, // will be deleted from process.env
})If you want to remove all existing properties and just set some, use option clear: true
let restore = mockedEnv(
{
FOO: 'foo',
BAR: 'bar',
},
{ clear: true }
)
// process.env = {FOO: 'foo', BAR: 'bar'}Again, calling restore() will restore the original full process.env object.
If you want to maintain the current environment and restore it to the original state after restore() is called, pass the 'restore' option.
let restore = mockedEnv(
{
FOO: 'foo',
BAR: 'bar',
},
{ restore: true }
)
// process.env = {...process.env, FOO: 'foo', BAR: 'bar'}These options are mutually exclusive and specifying them both will result in an error.
The options array can be passed as the first argument to the mockedEnv function as long as it contains either a 'restore' or 'clear' key, not both.
let restore = mockedEnv(
{ clear: true }
)
// process.env = {}process.env values should always be strings (Stackoverflow), any call to mockedEnv that attempts to use values other than strings (or undefined to signify that a property should be deleted) will raise an error.
const mockedEnv = require('mocked-env')
describe('changes variables', () => {
let restore // to restore old values
beforeEach(() => {
restore = mockedEnv({
PWD: '/foo/bar',
USER: undefined, // will be deleted from process.env
})
})
it('has changed process.env', () => {
// process.env.PWD = '/foo/bar'
})
afterEach(() => restore())
})You can also nest process.env reset and setting individual values in inner suites, see src/nested-spec.js. Great for tests that need to control process.env and would like to reset the entire thing, but then mock individual properties.
Run with DEBUG=mocked-env environment variable.
This package was inspired by burl/mock-env
Author: Gleb Bahmutov <gleb.bahmutov@gmail.com> © 2018
License: MIT - do anything with the code, but don't blame me if it does not work.
Support: if you find any problems with this module, email / tweet / open issue on Github
Copyright (c) 2018 Gleb Bahmutov <gleb.bahmutov@gmail.com>
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