1 files changed, 38 insertions, 0 deletions
diff --git a/js/src/tests/non262/String/at.js b/js/src/tests/non262/String/at.js
new file mode 100644
index 0000000000..c994d44de1
--- /dev/null
+++ b/js/src/tests/non262/String/at.js
@@ -0,0 +1,38 @@
+function basic() {
+  assertEq("a".at(0), "a");
+  assertEq("a".at(-1), "a");
+
+  assertEq("".at(0), undefined);
+  assertEq("".at(-1), undefined);
+  assertEq("".at(1), undefined);
+
+  assertEq("ab".at(0), "a");
+  assertEq("ab".at(1), "b");
+  assertEq("ab".at(-2), "a");
+  assertEq("ab".at(-1), "b");
+
+  assertEq("ab".at(2), undefined);
+  assertEq("ab".at(-3), undefined);
+  assertEq("ab".at(-4), undefined);
+  assertEq("ab".at(Infinity), undefined);
+  assertEq("ab".at(-Infinity), undefined);
+  assertEq("ab".at(NaN), "a"); // ToInteger(NaN) = 0
+
+  assertEq("\u{1f921}".at(0), "\u{d83e}");
+  assertEq("\u{1f921}".at(1), "\u{dd21}");
+}
+
+function other() {
+  var n = 146;
+  assertEq(String.prototype.at.call(n, 0), "1");
+  var obj = {};
+  assertEq(String.prototype.at.call(obj, -1), "]");
+  var b = true;
+  assertEq(String.prototype.at.call(b, 0), "t");
+}
+
+basic();
+other();
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);