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jest-environment-jsdom
Advanced tools
The jest-environment-jsdom package is a custom environment for Jest that allows you to simulate a browser-like environment using jsdom. This is useful for testing web applications without running them in an actual browser. It provides a simulated DOM API that you can interact with in your tests.
Simulating browser environment for testing
This feature allows you to simulate browser-like interactions such as clicking a button and then asserting the expected outcome, all within a Node.js environment.
test('simulates a click event', () => {
document.body.innerHTML = '<button id="button">Click me</button>';
const button = document.getElementById('button');
button.addEventListener('click', () => {
button.innerHTML = 'Clicked';
});
button.click();
expect(button.innerHTML).toBe('Clicked');
});
Testing DOM manipulation
You can test DOM manipulation by creating, modifying, and removing elements, and then asserting that these changes have taken place as expected.
test('adds a new div to the body', () => {
const div = document.createElement('div');
div.id = 'new-div';
document.body.appendChild(div);
expect(document.getElementById('new-div')).not.toBeNull();
});
Mocking global variables
The package allows you to mock global variables such as localStorage, which is useful for testing code that interacts with browser APIs that are not available in Node.js.
test('mocks a global variable', () => {
global.localStorage = {
getItem: jest.fn().mockReturnValue('mockValue')
};
expect(global.localStorage.getItem('key')).toBe('mockValue');
});
This package is similar to jest-environment-jsdom but is intended for testing Node.js applications. It does not simulate a browser environment and is therefore not suitable for testing browser-specific code.
Karma is a test runner that works with any framework and allows you to run tests in real browsers. Unlike jest-environment-jsdom, which simulates a browser environment, Karma actually runs tests in real browsers, which can be more accurate but also slower and more complex to set up.
This package integrates jsdom with Mocha, another testing framework. It provides similar functionality to jest-environment-jsdom but is designed to work with Mocha instead of Jest.
Enzyme is a testing utility for React that makes it easier to assert, manipulate, and traverse your React Components' output. It can be used in conjunction with jest-environment-jsdom to test React components in a simulated browser environment.
jest 16.0.0
jest <pattern>
is now case-insensitive.it.only
, it.skip
, test.only
, test.skip
and xtest
.--testNamePattern=pattern
or -t <pattern>
to run individual tests in test files.a
, o
, p
, q
or enter
while tests are running in the watch mode, the test run will be interrupted.--bail
now works together with --watch
.test.concurrent
for concurrent async tests..jsx
extension.jest.clearAllMocks
to clear all mocks manually.jest-snapshot
can now be more easily integrated into other test runners and used in other projects.fit
or when an error is thrown in a test.toHaveBeenLastCalledWith
, toHaveBeenCalledWith
, lastCalledWith
and toBeCalledWith
failure messages.toBeInstanceOf
matcher.toContainEqual
matcher.toThrowErrorMatchingSnapshot
matcher.moduleNameMapper
resolution.setupTestFrameworkScriptFile
script to make it easier to use chai together with Jest.--findRelatedTests <fileA> <fileB>
cli option to run tests related to the specified files.jest.deepUnmock
to babel-plugin-jest-hoist
.jest.runTimersToTime
which is useful together with fake timers.FAQs
Unknown package
The npm package jest-environment-jsdom receives a total of 12,290,403 weekly downloads. As such, jest-environment-jsdom popularity was classified as popular.
We found that jest-environment-jsdom demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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