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diff --git a/js/src/tests/test262/built-ins/Array/prototype/with/index-casted-to-number.js b/js/src/tests/test262/built-ins/Array/prototype/with/index-casted-to-number.js
new file mode 100644
index 0000000000..e0543723e0
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+++ b/js/src/tests/test262/built-ins/Array/prototype/with/index-casted-to-number.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.with
+description: >
+  Array.prototype.with casts the index to an integer.
+info: |
+  Array.prototype.with ( index, value )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  3. Let relativeIndex be ? ToIntegerOrInfinity(index).
+  4. If index >= 0, let actualIndex be relativeIndex.
+  5. Else, let actualIndex be len + relativeIndex.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [0, 4, 16];
+
+assert.compareArray(arr.with(1.2, 7), [0, 7, 16]);
+assert.compareArray(arr.with("1", 3), [0, 3, 16]);
+assert.compareArray(arr.with("-1", 5), [0, 4, 5]);
+assert.compareArray(arr.with(NaN, 2), [2, 4, 16]);
+assert.compareArray(arr.with("dog", "cat"), ["cat", 4, 16]);
+
+reportCompare(0, 0);