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// |reftest| skip -- Temporal is not supported
// Copyright (C) 2022 Igalia, S.L. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: >
Verify the time zone arithmetic used in TemporalHelpers.oneShiftTimeZone()
against known cases in the implementation's time zone database
includes: [compareArray.js, temporalHelpers.js]
features: [Temporal]
---*/
function checkTimeZoneArithmetic(shiftInstant, shiftNs, realTimeZoneName, shiftWallTime) {
// No need to test this on hosts that don't provide an Intl object. It's
// sufficient that the logic is tested on at least one host.
if (typeof globalThis.Intl === "undefined")
return;
const tz = TemporalHelpers.oneShiftTimeZone(shiftInstant, shiftNs);
const realTz = new Temporal.TimeZone(realTimeZoneName);
assert.sameValue(
tz.getOffsetNanosecondsFor(shiftInstant),
realTz.getOffsetNanosecondsFor(shiftInstant),
'offset at shift instant'
);
const minus1 = shiftInstant.subtract({ hours: 1 });
assert.sameValue(
tz.getOffsetNanosecondsFor(minus1),
realTz.getOffsetNanosecondsFor(minus1),
'offset at 1 hour before shift'
);
const plus1 = shiftInstant.add({ hours: 1 });
assert.sameValue(
tz.getOffsetNanosecondsFor(plus1),
realTz.getOffsetNanosecondsFor(plus1),
'offset at 1 hour after shift'
);
assert.compareArray(
tz.getPossibleInstantsFor(shiftWallTime).map((i) => i.epochNanoseconds),
realTz.getPossibleInstantsFor(shiftWallTime).map((i) => i.epochNanoseconds),
'possible instants for wall time'
);
const before1 = shiftWallTime.subtract({ hours: 1 });
assert.compareArray(
tz.getPossibleInstantsFor(before1).map((i) => i.epochNanoseconds),
realTz.getPossibleInstantsFor(before1).map((i) => i.epochNanoseconds),
'possible instants for 1 hour before wall time'
);
const after1 = shiftWallTime.add({ hours: 1 });
assert.compareArray(
tz.getPossibleInstantsFor(after1).map((i) => i.epochNanoseconds),
realTz.getPossibleInstantsFor(after1).map((i) => i.epochNanoseconds),
'possible instants for 1 hour after wall time'
);
}
// Check a positive DST shift from +00:00 to +01:00
checkTimeZoneArithmetic(
new Temporal.Instant(1616893200000000000n),
3600e9,
'Europe/London',
new Temporal.PlainDateTime(2021, 3, 28, 1)
);
// Check a negative DST shift from +00:00 to -01:00
checkTimeZoneArithmetic(
new Temporal.Instant(1635642000000000000n),
-3600e9,
'Atlantic/Azores',
new Temporal.PlainDateTime(2021, 10, 31, 1)
);
// Check the no-shift case
checkTimeZoneArithmetic(
new Temporal.Instant(0n),
0,
'UTC',
new Temporal.PlainDateTime(1970, 1, 1)
);
reportCompare(0, 0);
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