1 files changed, 22 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/String/prototype/at/returns-undefined-for-out-of-range-index.js b/js/src/tests/test262/built-ins/String/prototype/at/returns-undefined-for-out-of-range-index.js
new file mode 100644
index 0000000000..4be2a96b67
--- /dev/null
+++ b/js/src/tests/test262/built-ins/String/prototype/at/returns-undefined-for-out-of-range-index.js
@@ -0,0 +1,22 @@
+// 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: >
+  Creates an iterator from a custom object.
+info: |
+  String.prototype.at( index )
+
+  If k < 0 or k ≥ len, then return undefined.
+features: [String.prototype.at]
+---*/
+assert.sameValue(typeof String.prototype.at, 'function');
+
+let s = "";
+
+assert.sameValue(s.at(-2), undefined, 's.at(-2) must return undefined'); // wrap around the end
+assert.sameValue(s.at(0), undefined, 's.at(0) must return undefined');
+assert.sameValue(s.at(1), undefined, 's.at(1) must return undefined');
+
+
+reportCompare(0, 0);