accounts-frontend/jest/setupAfterEnv.js

import 'polyfills';
import { configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

configure({ adapter: new Adapter() });

if (!window.localStorage) {
  window.localStorage = {
    getItem(key) {
      return this[key] || null;
    },
    setItem(key, value) {
      this[key] = value;
    },
    removeItem(key) {
      delete this[key];
    },
  };

  window.sessionStorage = {
    ...window.localStorage,
  };
}