From 48c56238b62b740c891a89d0d8dcffd2bb023abc Mon Sep 17 00:00:00 2001
From: Jesse Alama <jesse@igalia.com>
Date: Fri, 7 Nov 2025 20:44:13 -0800
Subject: [PATCH] Intl Era Monthcode: Era boundary tests for roc calendar

Co-Authored-By: Philip Chimento <pchimento@igalia.com>
---
 .../prototype/add/era-boundary-roc.js         | 63 +++++++++++++++++++
 .../prototype/subtract/era-boundary-roc.js    | 63 +++++++++++++++++++
 .../prototype/add/era-boundary-roc.js         | 63 +++++++++++++++++++
 .../prototype/subtract/era-boundary-roc.js    | 63 +++++++++++++++++++
 .../prototype/add/era-boundary-roc.js         | 63 +++++++++++++++++++
 .../prototype/subtract/era-boundary-roc.js    | 63 +++++++++++++++++++
 6 files changed, 378 insertions(+)
 create mode 100644 test/intl402/Temporal/PlainDate/prototype/add/era-boundary-roc.js
 create mode 100644 test/intl402/Temporal/PlainDate/prototype/subtract/era-boundary-roc.js
 create mode 100644 test/intl402/Temporal/PlainDateTime/prototype/add/era-boundary-roc.js
 create mode 100644 test/intl402/Temporal/PlainDateTime/prototype/subtract/era-boundary-roc.js
 create mode 100644 test/intl402/Temporal/ZonedDateTime/prototype/add/era-boundary-roc.js
 create mode 100644 test/intl402/Temporal/ZonedDateTime/prototype/subtract/era-boundary-roc.js

diff --git a/test/intl402/Temporal/PlainDate/prototype/add/era-boundary-roc.js b/test/intl402/Temporal/PlainDate/prototype/add/era-boundary-roc.js
new file mode 100644
index 0000000000..646b64396b
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/prototype/add/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.add
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(1);
+const duration1n = new Temporal.Duration(-1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.PlainDate.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date1.add(duration1),
+  0, 6, "M06", 15, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.PlainDate.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date2.add(duration1),
+  1, 6, "M06", 15, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.PlainDate.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date3.add(duration1),
+  2, 6, "M06", 15, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.PlainDate.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date4.add(new Temporal.Duration(10)),
+  6, 3, "M03", 1, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.PlainDate.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date5.add(duration1n),
+  4, 6, "M06", 15, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDate(
+  date3.add(duration1n),
+  0, 6, "M06", 15, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.PlainDate.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date6.add(new Temporal.Duration(-15)),
+  -5, 3, "M03", 1, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);
diff --git a/test/intl402/Temporal/PlainDate/prototype/subtract/era-boundary-roc.js b/test/intl402/Temporal/PlainDate/prototype/subtract/era-boundary-roc.js
new file mode 100644
index 0000000000..3856ec5d03
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/prototype/subtract/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.subtract
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(-1);
+const duration1n = new Temporal.Duration(1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.PlainDate.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date1.subtract(duration1),
+  0, 6, "M06", 15, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.PlainDate.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date2.subtract(duration1),
+  1, 6, "M06", 15, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.PlainDate.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date3.subtract(duration1),
+  2, 6, "M06", 15, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.PlainDate.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date4.subtract(new Temporal.Duration(-10)),
+  6, 3, "M03", 1, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.PlainDate.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date5.subtract(duration1n),
+  4, 6, "M06", 15, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDate(
+  date3.subtract(duration1n),
+  0, 6, "M06", 15, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.PlainDate.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, calendar }, options);
+TemporalHelpers.assertPlainDate(
+  date6.subtract(new Temporal.Duration(15)),
+  -5, 3, "M03", 1, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/add/era-boundary-roc.js b/test/intl402/Temporal/PlainDateTime/prototype/add/era-boundary-roc.js
new file mode 100644
index 0000000000..b83f6e343e
--- /dev/null
+++ b/test/intl402/Temporal/PlainDateTime/prototype/add/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.add
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(1);
+const duration1n = new Temporal.Duration(-1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date1.add(duration1),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date2.add(duration1),
+  1, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date3.add(duration1),
+  2, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date4.add(new Temporal.Duration(10)),
+  6, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date5.add(duration1n),
+  4, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date3.add(duration1n),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date6.add(new Temporal.Duration(-15)),
+  -5, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/subtract/era-boundary-roc.js b/test/intl402/Temporal/PlainDateTime/prototype/subtract/era-boundary-roc.js
new file mode 100644
index 0000000000..c8858bc4af
--- /dev/null
+++ b/test/intl402/Temporal/PlainDateTime/prototype/subtract/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.subtract
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(-1);
+const duration1n = new Temporal.Duration(1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date1.subtract(duration1),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date2.subtract(duration1),
+  1, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date3.subtract(duration1),
+  2, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.PlainDateTime.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date4.subtract(new Temporal.Duration(-10)),
+  6, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date5.subtract(duration1n),
+  4, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date3.subtract(duration1n),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.PlainDateTime.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, hour: 12, minute: 34, calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date6.subtract(new Temporal.Duration(15)),
+  -5, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/add/era-boundary-roc.js b/test/intl402/Temporal/ZonedDateTime/prototype/add/era-boundary-roc.js
new file mode 100644
index 0000000000..fc402d11a5
--- /dev/null
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/add/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.add
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(1);
+const duration1n = new Temporal.Duration(-1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date1.add(duration1).toPlainDateTime(),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date2.add(duration1).toPlainDateTime(),
+  1, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date3.add(duration1).toPlainDateTime(),
+  2, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date4.add(new Temporal.Duration(10)).toPlainDateTime(),
+  6, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date5.add(duration1n).toPlainDateTime(),
+  4, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date3.add(duration1n).toPlainDateTime(),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date6.add(new Temporal.Duration(-15)).toPlainDateTime(),
+  -5, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);
diff --git a/test/intl402/Temporal/ZonedDateTime/prototype/subtract/era-boundary-roc.js b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/era-boundary-roc.js
new file mode 100644
index 0000000000..5f8feea593
--- /dev/null
+++ b/test/intl402/Temporal/ZonedDateTime/prototype/subtract/era-boundary-roc.js
@@ -0,0 +1,63 @@
+// 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.subtract
+description: >
+  Adding years works correctly across era boundaries in calendars with eras
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const duration1 = new Temporal.Duration(-1);
+const duration1n = new Temporal.Duration(1);
+const calendar = "roc";
+const options = { overflow: "reject" };
+
+const date1 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 2, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date1.subtract(duration1).toPlainDateTime(),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 2 BROC lands in 1 BROC (counts backwards)",
+  "broc", 1
+);
+
+const date2 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date2.subtract(duration1).toPlainDateTime(),
+  1, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 BROC lands in 1 ROC (no year zero)",
+  "roc", 1
+);
+
+const date3 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 1, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date3.subtract(duration1).toPlainDateTime(),
+  2, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Adding 1 year to 1 ROC lands in 2 ROC",
+  "roc", 2
+);
+
+const date4 = Temporal.ZonedDateTime.from({ era: "broc", eraYear: 5, monthCode: "M03", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date4.subtract(new Temporal.Duration(-10)).toPlainDateTime(),
+  6, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Adding 10 years to 5 BROC lands in 6 ROC (no year zero)",
+  "roc", 6
+);
+
+const date5 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 5, monthCode: "M06", day: 15, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date5.subtract(duration1n).toPlainDateTime(),
+  4, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 5 lands in ROC 4",
+  "roc", 4
+);
+
+TemporalHelpers.assertPlainDateTime(
+  date3.subtract(duration1n).toPlainDateTime(),
+  0, 6, "M06", 15, 12, 34, 0, 0, 0, 0, "Subtracting 1 year from ROC 1 lands in BROC 1",
+  "broc", 1
+);
+
+const date6 = Temporal.ZonedDateTime.from({ era: "roc", eraYear: 10, monthCode: "M03", day: 1, hour: 12, minute: 34, timeZone: "UTC", calendar }, options);
+TemporalHelpers.assertPlainDateTime(
+  date6.subtract(new Temporal.Duration(15)).toPlainDateTime(),
+  -5, 3, "M03", 1, 12, 34, 0, 0, 0, 0, "Subtracting 15 years from ROC 10 lands in BROC 6",
+  "broc", 6
+);