import { es } from "date-fns/locale/es"; import { formatMonthDropdown } from "./formatMonthDropdown"; const date = new Date(2022, 10, 21); test("should return the formatted month dropdown label", () => { expect(formatMonthDropdown(date.getMonth())).toEqual("November"); }); describe("when a locale is passed in", () => { test("should format using the locale", () => { expect(formatMonthDropdown(date.getMonth(), es)).toEqual("noviembre"); }); });