accounts-frontend/tests-e2e/cypress/support/index.js

import './commands';

Cypress.on('window:before:load', (win) => {
    // Remove fetch to enable correct api mocking with the cypress xhr mocks
    win.fetch = null;
    // The browser extends the system's language. Not everyone so cool to use English on their workstation,
    // so we must force browser's language to be English to let tests, based on buttons labels, work
    Object.defineProperty(win.navigator, 'languages', {
        get() {
            return ['en-US', 'en'];
        },
    });
});