Jest mocks for React Redux

react_redux.test.js

import { useSelector, useDispatch } from 'react-redux' 

// It can receive two more parameters, the second one is to specify a factory instead of the jest's automocking feature
jest.mock('react-redux')  

it('should load some items in the component', () => { 
  // Returning a mock data from the store to test the behavior of the component
  useSelector.mockImplementation((cb) => cb({items: ['Hello World']})
  
  const { getByTestId } = render(<List />)
  
  expect(getByTestId).toContainTextElement('Hello World')
 )
 
 it('should be able to add new item', () => { 
    const { getByTestId } = render(<List />)

    // Unused mock function that can be used to custom implementations or to test calls 
    const dispatch = jest.fn()
    
    // Every time that the useDispatch be called, it's gonna call the mock function
    useDispatch.mockReturnValue(dispatch)
    
    fireEvent.change(getByTestId('input', { target: { value: 'Hello World' } }) 
    fireEvent.submit(getByTestId('form'))
   
    expect(dispatch).toBeCalledWith({type: 'ADD_ITEM', payload: { item: 'Hello World'}})
 })