jest-environment-node

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'),
}));