Chatwoot/app/javascript/portal/specs/portal.spec.js

import { navigateToLocalePage } from '../portalHelpers';

describe('#navigateToLocalePage', () => {
  it('returns correct cookie name', () => {
    const elemDiv = document.createElement('div');
    elemDiv.classList.add('locale-switcher');
    document.body.appendChild(elemDiv);

    const allLocaleSwitcher = document.querySelector('.locale-switcher');

    allLocaleSwitcher.addEventListener = jest
      .fn()
      .mockImplementationOnce((event, callback) => {
        callback({ target: { value: 1 } });
      });

    navigateToLocalePage();
    expect(allLocaleSwitcher.addEventListener).toBeCalledWith(
      'change',
      expect.any(Function)
    );
  });
});