jest.setup.js

// Optional: configure or set up a testing framework before each test.
// If you delete this file, remove `setupFilesAfterEnv` from `jest.config.js`

// Used for __tests__/testing-library.js
// Learn more: https://github.com/testing-library/jest-dom
import '@testing-library/jest-dom/extend-expect'
import { TextDecoder, TextEncoder } from 'util'

global.setImmediate = jest.useRealTimers
global.TextDecoder = TextDecoder
global.TextEncoder = TextEncoder

Object.defineProperty(window, 'matchMedia', {
  writable: true,
  value: jest.fn().mockImplementation((query) => ({
    matches: false,
    media: query,
    onchange: null,
    addListener: jest.fn(), // Deprecated
    removeListener: jest.fn(), // Deprecated
    addEventListener: jest.fn(),
    removeEventListener: jest.fn(),
    dispatchEvent: jest.fn(),
  })),
})

window.IntersectionObserver = jest.fn(() => ({
  observe: jest.fn(),
  unobserve: jest.fn(),
  disconnect: jest.fn(),
}))

jest.mock('next/dynamic', () => () => {
  const DynamicComponent = () => null
  DynamicComponent.displayName = 'LoadableComponent'
  DynamicComponent.preload = jest.fn()
  return DynamicComponent
})