Intl era monthcode: PlainYearMonth tests, part 1

harness/temporalHelpers.js

@@ -334,9 +334,15 @@ var TemporalHelpers = {
    * equal to an expected value. (Except the `calendar` property, since callers
    * may want to assert either object equality with an object they put in there,
    * or the value of yearMonth.calendarId.)
+   *
+   * Pass null as the referenceISODay if you don't want to give it explicitly.
+   * In that case, the expected referenceISODay will be computed using PlainDate
+   * and only verified for consistency, not for equality with a specific value.
    */
   assertPlainYearMonth(yearMonth, year, month, monthCode, description = "", era = undefined, eraYear = undefined, referenceISODay = 1) {
     const prefix = description ? `${description}: ` : "";
+    assert(typeof referenceISODay === "number" || referenceISODay === null,
+      `TemporalHelpers.assertPlainYearMonth() referenceISODay argument should be a number or null, not ${referenceISODay}`);
     assert(yearMonth instanceof Temporal.PlainYearMonth, `${prefix}instanceof`);
     assert.sameValue(
       TemporalHelpers.canonicalizeCalendarEra(yearMonth.calendarId, yearMonth.era),
@@ -348,7 +354,8 @@ var TemporalHelpers = {
     assert.sameValue(yearMonth.month, month, `${prefix}month result:`);
     assert.sameValue(yearMonth.monthCode, monthCode, `${prefix}monthCode result:`);
     const isoDay = Number(yearMonth.toString({ calendarName: "always" }).slice(1).split("-")[2].slice(0, 2));
-    assert.sameValue(isoDay, referenceISODay, `${prefix}referenceISODay result:`);
+    const expectedISODay = referenceISODay ?? yearMonth.toPlainDate({ day: 1 }).withCalendar("iso8601").day;
+    assert.sameValue(isoDay, expectedISODay, `${prefix}referenceISODay result:`);
   },
 
   /*

test/intl402/Temporal/PlainYearMonth/from/basic-hebrew.js

@@ -0,0 +1,26 @@
+// 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.plainyearmonth.from
+description: Basic functionality of resolving fields in hebrew calendar
+features: [Temporal, Intl.Era-monthcode]
+includes: [temporalHelpers.js]
+---*/
+
+const calendar = "hebrew";
+const options = { overflow: "reject" };
+
+const commonYear = 5783;
+
+for (let month = 1; month < 13; month++) {
+  const monthCode = `M${String(month).padStart(2, '0')}`;
+
+  const startOfMonth = Temporal.PlainYearMonth.from({ year: commonYear, month, calendar }, options);
+  TemporalHelpers.assertPlainYearMonth(
+    startOfMonth,
+    commonYear, month, monthCode,
+    `${monthCode} in common year`,
+    "am", commonYear, null
+  );
+}

test/intl402/Temporal/PlainYearMonth/from/calendarresolvefields-error-ordering-gregory.js

@@ -0,0 +1,32 @@
+// 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.plainyearmonth.from
+description: CalendarResolveFields throws TypeError before RangeError (gregory calendar)
+info: |
+  CalendarResolveFields validates field types before validating field ranges,
+  ensuring TypeError is thrown before RangeError when both conditions exist.
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+// Missing year (and no era/eraYear) should throw TypeError even with month/monthCode conflict
+assert.throws(
+  TypeError,
+  () => Temporal.PlainYearMonth.from({ calendar: "gregory", monthCode: "M05", month: 6 }),
+  "Missing year/era throws TypeError before month/monthCode conflict throws RangeError"
+);
+
+// undefined year should throw TypeError even with month/monthCode conflict
+assert.throws(
+  TypeError,
+  () => Temporal.PlainYearMonth.from({ calendar: "gregory", year: undefined, monthCode: "M05", month: 6 }),
+  "undefined year throws TypeError before month/monthCode conflict throws RangeError"
+);
+
+// After type validation passes, range validation should throw RangeError
+assert.throws(
+  RangeError,
+  () => Temporal.PlainYearMonth.from({ calendar: "gregory", year: 2020, monthCode: "M05", month: 6 }),
+  "month/monthCode conflict throws RangeError when all types are valid"
+);

test/intl402/Temporal/PlainYearMonth/from/era-boundary-ethiopic.js

@@ -0,0 +1,36 @@
+// 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.plainyearmonth.from
+description: Non-positive era years are remapped in ethiopic calendar
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const calendar = "ethiopic";
+const options = { overflow: "reject" };
+
+const am0 = Temporal.PlainYearMonth.from({ era: "am", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  am0,
+  0, 1, "M01", "AM 0 resolves to AA 5500",
+  "aa", 5500, null);
+
+const am1n = Temporal.PlainYearMonth.from({ era: "am", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  am1n,
+  -1, 1, "M01", "AM -1 resolves to AA 5499",
+  "aa", 5499, null);
+
+const aa0 = Temporal.PlainYearMonth.from({ era: "aa", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  aa0,
+  -5500, 1, "M01", "AA 0 is not remapped",
+  "aa", 0, null);
+
+const aa1n = Temporal.PlainYearMonth.from({ era: "aa", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  aa1n,
+  -5501, 1, "M01", "AA -1 is not remapped",
+  "aa", -1, null);

test/intl402/Temporal/PlainYearMonth/from/era-boundary-gregory.js

@@ -0,0 +1,36 @@
+// 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.plainyearmonth.from
+description: Non-positive era years are remapped in gregory calendar
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const calendar = "gregory";
+const options = { overflow: "reject" };
+
+const ce0 = Temporal.PlainYearMonth.from({ era: "ce", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ce0,
+  0, 1, "M01", "CE 0 resolves to BCE 1",
+  "bce", 1);
+
+const ce1n = Temporal.PlainYearMonth.from({ era: "ce", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ce1n,
+  -1, 1, "M01", "CE -1 resolves to BCE 2",
+  "bce", 2);
+
+const bce0 = Temporal.PlainYearMonth.from({ era: "bce", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bce0,
+  1, 1, "M01", "BCE 0 resolves to CE 1",
+  "ce", 1);
+
+const bce1n = Temporal.PlainYearMonth.from({ era: "bce", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bce1n,
+  2, 1, "M01", "BCE -1 resolves to CE 2",
+  "ce", 2);

test/intl402/Temporal/PlainYearMonth/from/era-boundary-islamic-civil.js

@@ -0,0 +1,36 @@
+// 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.plainyearmonth.from
+description: Non-positive era years are remapped in islamic-civil calendar
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const calendar = "islamic-civil";
+const options = { overflow: "reject" };
+
+const ah0 = Temporal.PlainYearMonth.from({ era: "ah", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah0,
+  0, 1, "M01", "AH 0 resolves to BH 1",
+  "bh", 1, null);
+
+const ah1n = Temporal.PlainYearMonth.from({ era: "ah", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah1n,
+  -1, 1, "M01", "AH -1 resolves to BH 2",
+  "bh", 2, null);
+
+const bh0 = Temporal.PlainYearMonth.from({ era: "bh", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh0,
+  1, 1, "M01", "BH 0 resolves to AH 1",
+  "ah", 1, null);
+
+const bh1n = Temporal.PlainYearMonth.from({ era: "bh", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh1n,
+  2, 1, "M01", "BH -1 resolves to AH 2",
+  "ah", 2, null);

test/intl402/Temporal/PlainYearMonth/from/era-boundary-islamic-tbla.js

@@ -0,0 +1,36 @@
+// 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.plainyearmonth.from
+description: Non-positive era years are remapped in islamic-tbla calendar
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const calendar = "islamic-tbla";
+const options = { overflow: "reject" };
+
+const ah0 = Temporal.PlainYearMonth.from({ era: "ah", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah0,
+  0, 1, "M01", "AH 0 resolves to BH 1",
+  "bh", 1, null);
+
+const ah1n = Temporal.PlainYearMonth.from({ era: "ah", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah1n,
+  -1, 1, "M01", "AH -1 resolves to BH 2",
+  "bh", 2, null);
+
+const bh0 = Temporal.PlainYearMonth.from({ era: "bh", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh0,
+  1, 1, "M01", "BH 0 resolves to AH 1",
+  "ah", 1, null);
+
+const bh1n = Temporal.PlainYearMonth.from({ era: "bh", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh1n,
+  2, 1, "M01", "BH -1 resolves to AH 2",
+  "ah", 2, null);

test/intl402/Temporal/PlainYearMonth/from/era-boundary-islamic-umalqura.js

@@ -0,0 +1,36 @@
+// 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.plainyearmonth.from
+description: Non-positive era years are remapped in islamic-umalqura calendar
+includes: [temporalHelpers.js]
+features: [Temporal, Intl.Era-monthcode]
+---*/
+
+const calendar = "islamic-umalqura";
+const options = { overflow: "reject" };
+
+const ah0 = Temporal.PlainYearMonth.from({ era: "ah", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah0,
+  0, 1, "M01", "AH 0 resolves to BH 1",
+  "bh", 1, null);
+
+const ah1n = Temporal.PlainYearMonth.from({ era: "ah", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  ah1n,
+  -1, 1, "M01", "AH -1 resolves to BH 2",
+  "bh", 2, null);
+
+const bh0 = Temporal.PlainYearMonth.from({ era: "bh", eraYear: 0, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh0,
+  1, 1, "M01", "BH 0 resolves to AH 1",
+  "ah", 1, null);
+
+const bh1n = Temporal.PlainYearMonth.from({ era: "bh", eraYear: -1, monthCode: "M01", calendar }, options);
+TemporalHelpers.assertPlainYearMonth(
+  bh1n,
+  2, 1, "M01", "BH -1 resolves to AH 2",
+  "ah", 2, null);