import { es } from 'date-fns/locale'; import { labelWeekday } from './labelWeekday'; const weekDay = new Date(2022, 10, 21); test('should return the formatted weekday name', () => { expect(labelWeekday(weekDay)).toEqual('Monday'); }); describe('when a locale is passed in', () => { test('should format using the locale', () => { expect(labelWeekday(weekDay, { locale: es })).toEqual('lunes'); }); });