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// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
use icu_calendar::types::MonthCode;
use icu_calendar::AnyCalendar;
use icu_calendar::AnyCalendarKind;
use icu_calendar::Date;
#[cfg(test)]
use std::rc::Rc;
/// Reference: <https://tc39.es/proposal-intl-era-monthcode/#sec-temporal-calendardatearithmeticyear>
static EXTENDED_EPOCHS: &[(AnyCalendarKind, i32)] = &[
(AnyCalendarKind::Buddhist, -543),
(AnyCalendarKind::Chinese, 0),
(AnyCalendarKind::Coptic, 283),
(AnyCalendarKind::Dangi, 0),
(AnyCalendarKind::Ethiopian, 7),
(AnyCalendarKind::EthiopianAmeteAlem, -5493),
(AnyCalendarKind::Gregorian, 0),
(AnyCalendarKind::Hebrew, -3761),
(AnyCalendarKind::Indian, 78),
(AnyCalendarKind::HijriTabularTypeIIFriday, 621),
(AnyCalendarKind::HijriSimulatedMecca, 621),
(AnyCalendarKind::HijriTabularTypeIIThursday, 621),
(AnyCalendarKind::HijriUmmAlQura, 621),
(AnyCalendarKind::Iso, 0),
(AnyCalendarKind::Japanese, 0),
(AnyCalendarKind::JapaneseExtended, 0),
(AnyCalendarKind::Persian, 621),
(AnyCalendarKind::Roc, 1911),
];
#[test]
fn test_extended_year() {
let iso = icu_calendar::cal::Iso;
let m_01 = MonthCode::new_normal(1).unwrap();
for (kind, extended_epoch) in EXTENDED_EPOCHS.iter() {
let calendar = Rc::new(AnyCalendar::new(*kind));
// Create the first date in the epoch year (extended_year = 0)
let date_in_epoch_year =
Date::try_new_from_codes(None, 0, m_01, 1, calendar.clone()).unwrap();
let iso_date_in_epoch_year = date_in_epoch_year.to_calendar(iso);
assert_eq!(
iso_date_in_epoch_year.extended_year(),
*extended_epoch,
"Extended year for {date_in_epoch_year:?} should be {extended_epoch}"
);
// Test that for all calendars except Japanese, the *current* era is
// the same as that used for the extended year
// This date can be anything as long as it is vaguely modern.
//
// Note that this property is not *required* by the specification, new
// calendars may have epochs that do not follow this property. This
// property is strongly suggested by the specification as a rule of thumb
// to follow where possible.
let iso_date_in_2025 = Date::try_new_iso(2025, 1, 1).unwrap();
let date_in_2025 = iso_date_in_2025.to_calendar(calendar.clone());
// The extended year should align with the year in the modern era or related ISO.
// There is a special case for Japanese since it has a modern era but uses ISO for the extended year.
if matches!(
kind,
AnyCalendarKind::Japanese | AnyCalendarKind::JapaneseExtended
) {
assert_eq!(
date_in_2025.extended_year(),
2025,
"Extended year for {date_in_2025:?} should be 2025"
);
} else {
// Note: This code only works because 2025 is in the modern era for all calendars.
// These two function calls are not equivalent in general.
let expected = date_in_2025.year().era_year_or_related_iso();
assert_eq!(
date_in_2025.extended_year(),
expected,
"Extended year for {date_in_2025:?} should be {expected}"
);
}
}
}