blog/jest/__mocks__/gatsby.ts

import React from 'react'
const gatsby = jest.requireActual('gatsby')

export default {
  ...gatsby,
  graphql: jest.fn(),
  Link: jest
    .fn()
    .mockImplementation(({ to, ...rest }) =>
      React.createElement('a', { ...rest, href: to })
    ),
  StaticQuery: jest.fn(),
  useStaticQuery: jest.fn()
}