1 files changed, 44 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Temporal/ZonedDateTime/prototype/startOfDay/getoffsetnanosecondsfor-out-of-range-forward-offset-shift.js b/js/src/tests/test262/built-ins/Temporal/ZonedDateTime/prototype/startOfDay/getoffsetnanosecondsfor-out-of-range-forward-offset-shift.js
new file mode 100644
index 0000000000..82e86c4ee5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Temporal/ZonedDateTime/prototype/startOfDay/getoffsetnanosecondsfor-out-of-range-forward-offset-shift.js
@@ -0,0 +1,44 @@
+// |reftest| skip-if(!this.hasOwnProperty('Temporal')) -- Temporal is not enabled unconditionally
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.startofday
+description: >
+  UTC offset shift returned by adjacent invocations of getOffsetNanosecondsFor
+  in DisambiguatePossibleInstants cannot be greater than 24 hours.
+features: [Temporal]
+info: |
+  DisambiguatePossibleInstants:
+  18. If abs(_nanoseconds_) > nsPerDay, throw a *RangeError* exception.
+---*/
+
+class ShiftLonger24Hour extends Temporal.TimeZone {
+  id = 'TestTimeZone';
+  _shiftEpochNs = 0n
+
+  constructor() {
+    super('UTC');
+  }
+
+  getOffsetNanosecondsFor(instant) {
+    if (instant.epochNanoseconds < this._shiftEpochNs) return -12 * 3600e9;
+    return 12 * 3600e9 + 1;
+  }
+
+  getPossibleInstantsFor(plainDateTime) {
+    const [utcInstant] = super.getPossibleInstantsFor(plainDateTime);
+    const { year, month, day } = plainDateTime;
+
+    if (year < 1970) return [utcInstant.subtract({ hours: 12 })];
+    if (year === 1970 && month === 1 && day === 1) return [];
+    return [utcInstant.add({ hours: 12, nanoseconds: 1 })];
+  }
+}
+
+const timeZone = new ShiftLonger24Hour();
+
+const instance = new Temporal.ZonedDateTime(0n, timeZone);
+assert.throws(RangeError, () => instance.startOfDay(), "RangeError should be thrown");
+
+reportCompare(0, 0);