diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/string-iterator-generic.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/string-iterator-generic.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,25 @@
+// String.prototype.iterator is generic.
+
+load(libdir + "asserts.js");
+load(libdir + "iteration.js");
+load(libdir + "string.js");
+
+function test(obj) {
+    var it = String.prototype[std_iterator].call(obj);
+    var s = String(obj);
+    for (var i = 0, length = s.length; i < length;) {
+        var r = s[i++];
+        if (isHighSurrogate(r) && i < length && isLowSurrogate(s[i])) {
+            r += s[i++];
+        }
+        assertIteratorNext(it, r);
+    }
+    assertIteratorDone(it, undefined);
+}
+
+test({toString: () => ""});
+test({toString: () => "xyz"});
+test({toString: () => "\ud808\udf45"});
+test({valueOf: () => ""});
+test({valueOf: () => "xyz"});
+test({valueOf: () => "\ud808\udf45"});