Temporal: Add order-of-operations tests for toPlainDate

Add order-of-operations tests for toPlainDate for PlainMonthDay
and PlainYearMonth

test/built-ins/Temporal/PlainMonthDay/prototype/toPlainDate/order-of-operations.js

@@ -0,0 +1,29 @@
+// 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.plainmonthday.toplaindate
+description: Properties on an object passed to toPlainDate() are accessed in the correct order
+includes: [compareArray.js, temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const expected = [
+  "get fields.year",
+  "get fields.year.valueOf",
+  "call fields.year.valueOf",
+];
+const actual = [];
+
+const fields = TemporalHelpers.propertyBagObserver(actual, {
+  year: 1.7,
+  month: 1.7,
+  monthCode: "M01",
+  day: 1.7,
+  calendar: "iso8601",
+}, "fields", ["calendar"]);
+
+const pmd = new Temporal.PlainMonthDay(5, 2);
+
+pmd.toPlainDate(fields);
+assert.compareArray(actual, expected, "order of operations");

test/built-ins/Temporal/PlainYearMonth/prototype/toPlainDate/order-of-operations.js

@@ -0,0 +1,29 @@
+// 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.toplaindate
+description: Properties on an object passed to toPlainDate() are accessed in the correct order
+includes: [compareArray.js, temporalHelpers.js]
+features: [Temporal]
+---*/
+
+const expected = [
+  "get fields.day",
+  "get fields.day.valueOf",
+  "call fields.day.valueOf",
+];
+const actual = [];
+
+const fields = TemporalHelpers.propertyBagObserver(actual, {
+  year: 1.7,
+  month: 1.7,
+  monthCode: "M01",
+  day: 1,
+  calendar: "iso8601",
+}, "fields", ["calendar"]);
+
+const pym = new Temporal.PlainYearMonth(2005, 2);
+
+pym.toPlainDate(fields);
+assert.compareArray(actual, expected, "order of operations");