text: describe("correct behavior", () => {
      test("basic functionality", () => {
          const calendar = { hello: "friends" };
          const plain_date = new Temporal.PlainDate(1, 1, 1, calendar);
          expect(plain_date.calendar).toBe(calendar);
      });
  });
  
  test("errors", () => {
      test("this value must be a Temporal.Duration object", () => {
          expect(() => {
              Reflect.get(Temporal.PlainDate.prototype, "calendar", "foo");
          }).toThrowWithMessage(TypeError, "Not a Temporal.PlainDate");
      });
  });
  