jest-hooks.js

/* testing/src/helpers/index.js */

// ...

const setTraysForId = (id, trays) => {
  window.localStorage.setItem(`${id}`, JSON.stringify(trays));
}

const getTraysForId = (id) => {
  return JSON.parse(window.localStorage.getItem(`${id}`));
}

export { /* ... */, setTraysForId, getTraysForId };