jest-environment-node

What is jest-environment-node?

The jest-environment-node npm package is a test environment for Jest that simulates a Node.js environment. It is used when testing Node.js specific code. It provides a global environment that's set up for each test file to be executed in a Node-like environment, with all the necessary globals like `process` and `Buffer` available.

What are jest-environment-node's main functionalities?

Simulating Node.js Environment

This configuration in Jest's setup file tells Jest to use the Node environment for testing. It is useful when you want to test code that relies on Node.js APIs.

module.exports = { testEnvironment: 'jest-environment-node' };

Global Setup and Teardown

This feature allows you to extend the Node environment to add custom setup and teardown logic that runs before and after each test suite.

class CustomEnvironment extends NodeEnvironment {
  async setup() {
    await super.setup();
    // Your setup code here
  }

  async teardown() {
    // Your teardown code here
    await super.teardown();
  }
}

Custom Module Mocking

In a Node environment, you can mock Node modules like 'fs' to control their behavior during tests, which is useful for testing code that interacts with the filesystem without actually reading or writing files.

jest.mock('fs', () => ({
  readFileSync: jest.fn().mockReturnValue('mocked content'),
}));

Other packages similar to jest-environment-node

jest-environment-jsdom

This package is similar to jest-environment-node but is intended for testing web applications by simulating a browser environment using jsdom. It provides a DOM API that can be used in tests.

jest-environment-puppeteer

This package integrates Jest with Puppeteer for end-to-end testing. It sets up a browser environment and allows for testing user interactions with a real browser.

jest-environment-webdriver

This package is designed for integration with Selenium WebDriver for browser-based testing. It is similar to jest-environment-puppeteer but uses WebDriver API for controlling browsers.

README

The README file is missing

Changelog

30.0.4

Features

• [expect] The Inverse type is now exported (#15714)
• [expect] feat: support async functions in toBe (#15704)

Fixes

• [jest] jest --onlyFailures --listTests now correctly lists only failed tests (#15700)
• [jest-snapshot] Handle line endings in snapshots (#15708)