Temporal: Update tests to account for use of year in ToTemporalMonthDay

Ref tc39/proposal-temporal#2863
Normative PR: tc39/proposal-temporal#2940

test/intl402/Temporal/PlainMonthDay/from/reference-year-1972.js

@@ -10,22 +10,28 @@ features: [Temporal]
 
 const result1 = Temporal.PlainMonthDay.from({ year: 2021, monthCode: "M02", day: 29, calendar: "gregory" });
 TemporalHelpers.assertPlainMonthDay(
-  result1, "M02", 29,
-  "year is ignored and reference year should be 1972 if monthCode is given",
+  result1, "M02", 28,
+  "year and monthCode determine if calendar date exists, but reference year should be 1972",
   1972
 );
 
 const result2 = Temporal.PlainMonthDay.from({ year: 2021, month: 2, day: 29, calendar: "gregory" }, { overflow: "constrain" });
 TemporalHelpers.assertPlainMonthDay(
   result2, "M02", 28,
-  "if monthCode is not given, year is used to determine if calendar date exists, but reference year should still be 1972",
+  "year and month determine if calendar date exists, but reference year should be 1972",
   1972
 );
 
+assert.throws(
+  RangeError,
+  () => Temporal.PlainMonthDay.from({ year: 2021, monthCode: "M02", day: 29, calendar: "gregory" }, { overflow: "reject" }),
+  "RangeError thrown if monthCode and day does not exist in given year and overflow is reject"
+);
+
 assert.throws(
   RangeError,
   () => Temporal.PlainMonthDay.from({ year: 2021, month: 2, day: 29, calendar: "gregory" }, { overflow: "reject" }),
-  "RangeError thrown if calendar date does not exist in given year and overflow is reject"
+  "RangeError thrown if month and day does not exist in given year and overflow is reject"
 );
 
 const result3 = Temporal.PlainMonthDay.from({ monthCode: "M01", day: 1, calendar: "hebrew" });
@@ -44,28 +50,41 @@ TemporalHelpers.assertPlainMonthDay(
 
 const result5 = Temporal.PlainMonthDay.from({ year: 5781, monthCode: "M02", day: 30, calendar: "hebrew" });
 TemporalHelpers.assertPlainMonthDay(
-  result5, "M02", 30,
-  "year is ignored if monthCode is given (Cheshvan 5781 has 29 days)",
-  1971
+  result5, "M02", 29,
+  "year and monthCode determine if calendar date exists, and reference year must agree (Cheshvan 5781 has 29 days)",
+  1972
 );
 
 const result6 = Temporal.PlainMonthDay.from({ year: 5781, month: 2, day: 30, calendar: "hebrew" }, { overflow: "constrain" });
 TemporalHelpers.assertPlainMonthDay(
   result6, "M02", 29,
-  "if monthCode is not given, year is used to determine if calendar date exists, but reference year still correct",
+  "year and month determine if calendar date exists, and reference year must agree (Cheshvan 5781 has 29 days)",
   1972
 );
 
+const result7 = Temporal.PlainMonthDay.from({ monthCode: "M02", day: 30, calendar: "hebrew" });
+TemporalHelpers.assertPlainMonthDay(
+  result7, "M02", 30,
+  "reference year must be the latest ISO year at or before 1972 that includes monthCode and day (Cheshvan 5781 has 29 days)",
+  1971
+);
+
+assert.throws(
+  RangeError,
+  () => Temporal.PlainMonthDay.from({ year: 5781, monthCode: "M02", day: 30, calendar: "hebrew" }, { overflow: "reject" }),
+  "RangeError thrown if monthCode and day does not exist in given year and overflow is reject"
+);
+
 assert.throws(
   RangeError,
   () => Temporal.PlainMonthDay.from({ year: 5781, month: 2, day: 30, calendar: "hebrew" }, { overflow: "reject" }),
-  "RangeError thrown if calendar date does not exist in given year and overflow is reject"
+  "RangeError thrown if month and day does not exist in given year and overflow is reject"
 );
 
-const result7 = Temporal.PlainMonthDay.from({ monthCode: "M04", day: 26, calendar: "hebrew" });
+const result8 = Temporal.PlainMonthDay.from({ monthCode: "M04", day: 26, calendar: "hebrew" });
 TemporalHelpers.assertPlainMonthDay(
-  result7, "M04", 26,
+  result8, "M04", 26,
   "reference date should be the later one, if two options exist in ISO year 1972",
   1972
 );
-assert.sameValue(result7.toString(), "1972-12-31[u-ca=hebrew]", "reference date");
+assert.sameValue(result8.toString(), "1972-12-31[u-ca=hebrew]", "reference date");