I have a test that imports a component that in turn imports a helper file that uses the window object to pull out a query string parameter. I get the following error about window:
FAIL src/js/components/__tests__/Controls.test.jsx ● Test suite failed to run ReferenceError: window is not defined Controls.jsx:
import { Unwrapped as Controls } from '../Controls' describe('<MyInterestsControls />', () => { it('should render the component with the fixture data', () => { const component = shallow( <UnwrappedMyInterestControls dashboardData={dashboardData} loadingFlags={{ controls: false }} /> ) expect(component).toMatchSnapshot() }) }) Controls.jsx imports ./helpers/services.js which contains the following:
import * as queryString from 'query-string' const flag = queryString.parse(window.location.search).flag || 'off' ^^^^^^ this seems to be the problem I have attempted to import jsdom
import { JSDOM } from 'jsdom' And implement the solution presented here at the top of my test file:
const { JSDOM } = require('jsdom'); const jsdom = new JSDOM('<!doctype html><html><body></body></html>'); const { window } = jsdom; function copyProps(src, target) { const props = Object.getOwnPropertyNames(src) .filter(prop => typeof target[prop] === 'undefined') .map(prop => Object.getOwnPropertyDescriptor(src, prop)); Object.defineProperties(target, props); } global.window = window; global.document = window.document; global.navigator = { userAgent: 'node.js', }; copyProps(window, global); however I still get the error and it seems JSDOM's window object isn't exposed to the test.
How can I properly expose global objects like window or document to a jest test?
relevant package.json "scripts": { "test:watch": "NODE_ENV=test jest --watch" }, ... "devDependencies": { ... "jest": "^20.0.4", "jest-mock": "^21.2.0", "jsdom": "^11.0.0", ... }, ... "jest": { "verbose": true, "collectCoverageFrom": [ "src/js/helpers/preparePayload.js", "src/js/components-ni", "!**/node_modules/**", "!**/dist/**" ], "coverageThreshold": { "global": { "statements": 50, "branches": 50, "functions": 50, "lines": 75 } }, "testEnvironment": "jest-environment-node" } 6 Answers
Answers 1
Your problem relies on the configuration.
In the moment you set:
"testEnvironment": "jest-environment-node" you are changing the default configuration from jest which is browser-like to jest-environment-node (node-like) meaning that your test will be run under a NodeJs environment
To solve it either you set your testEnvironment to jsdom
Or you remove the testEnvironment from your config so it will take the default value in yourpackage.json:
... "jest": { "verbose": true, "collectCoverageFrom": [ "src/js/helpers/preparePayload.js", "src/js/components-ni", "!**/node_modules/**", "!**/dist/**" ], "coverageThreshold": { "global": { "statements": 50, "branches": 50, "functions": 50, "lines": 75 } } } This is what they say in the documentation:
testEnvironment[string] # Default: "jsdom"The test environment that will be used for testing. The default environment in Jest is a browser-like environment through jsdom. If you are building a node service, you can use the node option to use a node-like environment instead.
Do you need the `node` environment?
As I could see, your tests are meant to be run under a browser-like environment.
If you ever need an explicit node environment, better you isolate that case using @jest-environment:
/** * @jest-environment node */ test('use node in this test file', () => { expect(true).not.toBeNull(); }); or the other way around if you are meant to run the tests under node environment
/** * @jest-environment jsdom */ test('use jsdom in this test file', () => { const element = document.createElement('div'); expect(element).not.toBeNull(); }); Conclusion
With this you can avoid importing jsdom manually and setting global variables, jsdom will mock the DOM implementation automatically.
If you need to change the environment for your tests use the notation @jest-environment
Answers 2
You could try doing
global.window = new jsdom.JSDOM().window; global.document = window.document; Answers 3
https://github.com/facebook/jest/issues/2460#issuecomment-324630534
It seems like the one of the contributer declared that he is not planning expose jsdom to global under the jest environment.
However, you could use Object.defineProperty(window, 'location', {value: '…'} API to approach it, like the developer in Facebook do. In your case it could be like:
Object.defineProperty(window, 'location', { value: { search: ... }, }) Good luck!
Answers 4
Here you can find examples of how to do this:
https://www.codementor.io/pkodmad/dom-testing-react-application-jest-k4ll4f8sd
For example:
import {jsdom} from 'jsdom'; const documentHTML = '<!doctype html><html><body><div id="root"></div></body></html>'; global.document = jsdom(documentHTML); global.window = document.parentWindow; Answers 5
You can simply mock location:
global.location = {search: 'someSearchString'} Also note, that global in your test is the global context for the file to test (global === window)
Note this will only work if your module make the window.location call after the test has been finishing import all the modules.
export default () => window.location So if your module looks like this:
const l = window.location export default l it will not work. In this case you could mock the module using jest.mock.
Answers 6
Not sure but i think you could do it with jest.fn()
global.window = jest.fn(() => { location: { ... } }) maybe even as window = jest.fn(...)
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