1 files changed, 31 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/TypedArray/prototype/with/index-negative.js b/js/src/tests/test262/built-ins/TypedArray/prototype/with/index-negative.js
new file mode 100644
index 0000000000..3ac59b6926
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+++ b/js/src/tests/test262/built-ins/TypedArray/prototype/with/index-negative.js
@@ -0,0 +1,31 @@
+// |reftest| shell-option(--enable-change-array-by-copy) skip-if(!Array.prototype.with||!xulRuntime.shell) -- change-array-by-copy is not enabled unconditionally, requires shell-options
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-%typedarray%.prototype.with
+description: >
+  %TypedArray%.prototype.with adds length to index if it's negative.
+info: |
+  %TypedArray%.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: [TypedArray, change-array-by-copy]
+includes: [testTypedArray.js, compareArray.js]
+---*/
+
+testWithTypedArrayConstructors(TA => {
+  var arr = new TA([0, 1, 2]);
+
+  assert.compareArray(arr.with(-1, 4), [0, 1, 4]);
+  assert.compareArray(arr.with(-3, 4), [4, 1, 2]);
+  // -0 is not negative.
+  assert.compareArray(arr.with(-0, 4), [4, 1, 2]);
+});
+
+reportCompare(0, 0);