1 files changed, 31 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/fields/argument-throws-duplicate-keys.js b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/fields/argument-throws-duplicate-keys.js
new file mode 100644
index 0000000000..be868d3bf7
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/fields/argument-throws-duplicate-keys.js
@@ -0,0 +1,31 @@
+// |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.fields
+description: Duplicate fields are not allowed in the argument to Calendar.prototype.fields
+info: |
+    sec-temporal.calendar.prototype.fields step 7.b.iii:
+      iii. If _fieldNames_ contains _nextValue_, then
+        1. Let _completion_ be ThrowCompletion(a newly created *RangeError* object).
+        2. Return ? IteratorClose(_iteratorRecord_, _completion_).
+features: [Temporal]
+---*/
+
+const calendar = new Temporal.Calendar("iso8601");
+assert.throws(RangeError, () => calendar.fields(["day", "month", "day"]));
+assert.throws(RangeError, () => calendar.fields(["year", "month", "monthCode", "day", "year"]));
+
+const manyFields = {
+  count: 0
+};
+
+manyFields[Symbol.iterator] = function*() {
+  while (this.count++ < 100) yield "year";
+};
+
+assert.throws(RangeError, () => calendar.fields(manyFields), "Rejected duplicate values");
+assert.sameValue(manyFields.count, 2, "Rejected first duplicate value");
+
+reportCompare(0, 0);