1 files changed, 26 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/dateAdd/argument-plaindatetime.js b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/dateAdd/argument-plaindatetime.js
new file mode 100644
index 0000000000..a613cfe71e
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+++ b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/dateAdd/argument-plaindatetime.js
@@ -0,0 +1,26 @@
+// |reftest| skip-if(!this.hasOwnProperty('Temporal')) -- Temporal is not enabled unconditionally
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.dateadd
+description: Fast path for converting Temporal.PlainDateTime to Temporal.PlainDate by reading internal slots
+info: |
+    sec-temporal.calendar.prototype.dateadd step 4:
+      4. Set _date_ to ? ToTemporalDate(_date_).
+    sec-temporal-totemporaldate step 2.b:
+      b. If _item_ has an [[InitializedTemporalDateTime]] internal slot, then
+        i. Return ! CreateTemporalDate(_item_.[[ISOYear]], _item_.[[ISOMonth]], _item_.[[ISODay]], _item_.[[Calendar]]).
+includes: [compareArray.js, temporalHelpers.js]
+features: [Temporal]
+---*/
+
+TemporalHelpers.checkPlainDateTimeConversionFastPath((datetime) => {
+  const calendar = new Temporal.Calendar("iso8601");
+  const duration = new Temporal.Duration(0, 1);
+  const result = calendar.dateAdd(datetime, duration);
+  TemporalHelpers.assertPlainDate(result, 2000, 6, "M06", 2);
+  assert.sameValue(result.hour, undefined, "instance of PlainDate returned, not PlainDateTime");
+});
+
+reportCompare(0, 0);