Intl Era Monthcode: Leap month tests for with() methods

Adds coverage for the constrain behaviour around leap months when using
the with() method to change the year, for the three calendars with leap
months.

test/intl402/Temporal/PlainDate/prototype/with/leap-months-chinese.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.with
+description: Check constraining leap months when year changes in chinese calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "chinese";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDate.from({ year: 2017, monthCode: "M06L", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2025 }, options),
+  2025, 7, "M06L", 1, "month not constrained when moving to another leap year with M06L");
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2020 }),
+  2020, 7, "M06", 1, "month constrained when moving to another leap year without M06L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M06L");
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2024 }),
+  2024, 6, "M06", 1, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/PlainDate/prototype/with/leap-months-dangi.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.with
+description: Check constraining leap months when year changes in dangi calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "dangi";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDate.from({ year: 2017, monthCode: "M05L", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2009 }, options),
+  2009, 6, "M05L", 1, "month not constrained when moving to another leap year with M05L");
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2020 }),
+  2020, 6, "M05", 1, "month constrained when moving to another leap year without M05L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M05L");
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 2024 }),
+  2024, 5, "M05", 1, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/PlainDate/prototype/with/leap-months-hebrew.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.with
+description: Check constraining leap months when year changes in hebrew calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "hebrew";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDate.from({ year: 5784, monthCode: "M05L", day: 1, calendar }, options);
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 5782 }, options),
+  5782, 6, "M05L", 1, "month not constrained when moving to another leap year",
+  "am", 5782);
+
+TemporalHelpers.assertPlainDate(
+  leapMonth.with({ year: 5783 }),
+  5783, 6, "M06", 1, "month constrained when moving to a common year",
+  "am", 5783);
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 5783 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/PlainDateTime/prototype/with/leap-months-chinese.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.with
+description: Check constraining leap months when year changes in chinese calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "chinese";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDateTime.from({ year: 2017, monthCode: "M06L", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2025 }, options),
+  2025, 7, "M06L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year with M06L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2020 }),
+  2020, 7, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to another leap year without M06L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M06L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2024 }),
+  2024, 6, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/PlainDateTime/prototype/with/leap-months-dangi.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.with
+description: Check constraining leap months when year changes in dangi calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "dangi";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDateTime.from({ year: 2017, monthCode: "M05L", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2009 }, options),
+  2009, 6, "M05L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year with M05L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2020 }),
+  2020, 6, "M05", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to another leap year without M05L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M05L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2024 }),
+  2024, 5, "M05", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/PlainDateTime/prototype/with/leap-months-hebrew.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.with
+description: Check constraining leap months when year changes in hebrew calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "hebrew";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.PlainDateTime.from({ year: 5784, monthCode: "M05L", day: 1, hour: 12, minute: 34, calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 5782 }, options),
+  5782, 6, "M05L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year",
+  "am", 5782);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 5783 }),
+  5783, 6, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year",
+  "am", 5783);
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 5783 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/ZonedDateTime/prototype/with/leap-months-chinese.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.with
+description: Check constraining leap months when year changes in chinese calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "chinese";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.ZonedDateTime.from({ year: 2017, monthCode: "M06L", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2025 }, options).toPlainDateTime(),
+  2025, 7, "M06L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year with M06L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2020 }).toPlainDateTime(),
+  2020, 7, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to another leap year without M06L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M06L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2024 }).toPlainDateTime(),
+  2024, 6, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/ZonedDateTime/prototype/with/leap-months-dangi.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.with
+description: Check constraining leap months when year changes in dangi calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "dangi";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.ZonedDateTime.from({ year: 2017, monthCode: "M05L", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2009 }, options).toPlainDateTime(),
+  2009, 6, "M05L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year with M05L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2020 }).toPlainDateTime(),
+  2020, 6, "M05", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to another leap year without M05L");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2020 }, options);
+}, "reject when moving to another leap year without M05L");
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 2024 }).toPlainDateTime(),
+  2024, 5, "M05", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year");
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 2024 }, options);
+}, "reject when moving to a common year");

test/intl402/Temporal/ZonedDateTime/prototype/with/leap-months-hebrew.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.prototype.with
+description: Check constraining leap months when year changes in hebrew calendar
+features: [Temporal]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "hebrew";
+const options = { overflow: "reject" };
+const leapMonth = Temporal.ZonedDateTime.from({ year: 5784, monthCode: "M05L", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 5782 }, options).toPlainDateTime(),
+  5782, 6, "M05L", 1, 12, 34, 0, 0, 0, 0, "month not constrained when moving to another leap year",
+  "am", 5782);
+
+TemporalHelpers.assertPlainDateTime(
+  leapMonth.with({ year: 5783 }).toPlainDateTime(),
+  5783, 6, "M06", 1, 12, 34, 0, 0, 0, 0, "month constrained when moving to a common year",
+  "am", 5783);
+
+assert.throws(RangeError, function () {
+  leapMonth.with({ year: 5783 }, options);
+}, "reject when moving to a common year");