@Test
  @RegressionTest("https://issues.jboss.org/browse/RF-9646")
  public void testFirstWeekDay() {
    DayPicker proxiedDayPicker = calendar.openPopup().getProxiedDayPicker();
    List<String> weekDays = Arrays.asList("Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat");

    assertEquals(proxiedDayPicker.getWeekDayShortNames(), weekDays);

    // wrong input, nothing changes, RF-9646
    calendarAttributes.set(CalendarAttributes.firstWeekDay, 7);
    assertEquals(proxiedDayPicker.getWeekDayShortNames(), weekDays);

    calendarAttributes.set(CalendarAttributes.firstWeekDay, 1);
    Collections.rotate(weekDays, -1);
    assertEquals(proxiedDayPicker.getWeekDayShortNames(), weekDays);
  }
  @Test
  public void testLocale() {
    String locale = "ru";
    calendarAttributes.set(CalendarAttributes.locale, locale);
    DayPicker proxiedDayPicker = calendar.openPopup().getProxiedDayPicker();
    List<String> weekDayShortNames = proxiedDayPicker.getWeekDayShortNames();
    List<String> expectedShortNames = Arrays.asList("Вс", "Пн", "Вт", "Ср", "Чт", "Пт", "Сб");
    assertEquals(weekDayShortNames, expectedShortNames);

    setCurrentDateWithCalendarsTodayButtonAction.perform();
    DateTime parsedDateTime =
        dateTimeFormatter.withLocale(new Locale(locale)).parseDateTime(calendar.getInputValue());

    assertEquals(
        parsedDateTime.getDayOfMonth(),
        todayMidday.getDayOfMonth(),
        "Input doesn't contain selected date.");
    assertEquals(
        parsedDateTime.getMonthOfYear(),
        todayMidday.getMonthOfYear(),
        "Input doesn't contain selected date.");
    assertEquals(
        parsedDateTime.getYear(), todayMidday.getYear(), "Input doesn't contain selected date.");
  }