Vitest Mock Timezone

DateTimeFormatMock.js

it("should get the client timezone as a string", () => {
  const DateTimeFormat = Intl.DateTimeFormat;
  vi.spyOn(global.Intl, "DateTimeFormat").mockImplementation(
    (locale, options) =>
      new DateTimeFormat(locale, { ...options, timeZone: "Asia/Tehran" })
  );

  const date: MyDate = new MyDate("2023-03-28T11:06:48+00:00");

  expect(date.getClientTZ()).toEqual("Asia/Tehran");
});