1 files changed, 31 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/String/prototype/at/returns-item-relative-index.js b/js/src/tests/test262/built-ins/String/prototype/at/returns-item-relative-index.js
new file mode 100644
index 0000000000..9c3360f266
--- /dev/null
+++ b/js/src/tests/test262/built-ins/String/prototype/at/returns-item-relative-index.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-String.prototype.at
+description: >
+  Returns the item value at the specified relative index
+info: |
+  String.prototype.at ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfStringLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [String.prototype.at]
+---*/
+assert.sameValue(typeof String.prototype.at, 'function');
+
+let s = "12345";
+
+assert.sameValue(s.at(0), "1", 's.at(0) must return "1"');
+assert.sameValue(s.at(-1), "5", 's.at(-1) must return "5"');
+assert.sameValue(s.at(-3), "3", 's.at(-3) must return "3"');
+assert.sameValue(s.at(-4), "2", 's.at(-4) must return "2"');
+
+reportCompare(0, 0);