message: update PointerBox tests
diff: import React from 'react'
  import {PointerBox} from '..'
  import {render} from '../utils/testing'
  +import {render as HTMLRender, cleanup} from "@testing-library/react";
  +import {axe, toHaveNoViolations} from 'jest-axe'
  +import 'babel-polyfill'
  +expect.extend(toHaveNoViolations)
  +
  describe('PointerBox', () => {
  it('renders a <Caret> in <BorderBox> with relative positioning', () => {
  expect(render(<PointerBox />)).toMatchSnapshot()
  })
  + it('should have no axe violations', async () => {
  + const {container} = HTMLRender(<PointerBox/>)
  + const results = await axe(container)
  + expect(results).toHaveNoViolations()
  + cleanup()
  + })
  +
  it('passes the "borderColor" prop to both <BorderBox> and <Caret>', () => {
  expect(render(<PointerBox borderColor="red.5" />)).toMatchSnapshot()
  })
  