Code Snippet - Setup Function

import { render } from '@testing-library/react'  
import userEvent from '@testing-library/user-event'  
import * as React from 'react'  
  
import Login from '../login'  
  
async function setup() {  
	const handleSubmit = jest.fn()  
	const utils = await render(<Login onSubmit={handleSubmit} />)  
	const user = { username: 'michelle', password: 'smith' }  
	const changeUsernameInput = value =>  
		userEvent.type(utils.getByLabelText(/username/i), value)  
	const changePasswordInput = value =>  
		userEvent.type(utils.getByLabelText(/password/i), value)  
	const clickSubmit = () => userEvent.click(utils.getByText(/submit/i))  
	return {  
		...utils,  
		handleSubmit,  
		user,  
		changeUsernameInput,  
		changePasswordInput,  
		clickSubmit,  
	}  
}  
  
async function setupSuccessCase() {  
	const utils = await setup()  
	utils.changeUsernameInput(utils.user.username)  
	utils.changePasswordInput(utils.user.password)  
	utils.clickSubmit()  
	return utils  
}  
  
async function setupWithNoPassword() {  
	const utils = await setup()  
	utils.changeUsernameInput(utils.user.username)  
	utils.clickSubmit()  
	const errorMessage = utils.getByRole('alert')  
	return { ...utils, errorMessage }  
}  
  
async function setupWithNoUsername() {  
	const utils = await setup()  
	utils.changePasswordInput(utils.user.password)  
	utils.clickSubmit()  
	const errorMessage = utils.getByRole('alert')  
	return { ...utils, errorMessage }  
}  
  
test('calls onSubmit with the username and password', async () => {  
	const { handleSubmit, user } = await setupSuccessCase()  
	expect(handleSubmit).toHaveBeenCalledTimes(1)  
	expect(handleSubmit).toHaveBeenCalledWith(user)  
})  
  
test('shows an error message when submit is clicked and no username is provided', async () => {  
	const { handleSubmit, errorMessage } = await setupWithNoUsername()  
	expect(errorMessage).toHaveTextContent(/username is required/i)  
	expect(handleSubmit).not.toHaveBeenCalled()  
})  
  
test('shows an error message when password is not provided', async () => {  
	const { handleSubmit, errorMessage } = await setupWithNoPassword()  
	expect(errorMessage).toHaveTextContent(/password is required/i)  
	expect(handleSubmit).not.toHaveBeenCalled()  
})