JSTests/test262/test/built-ins/String/prototype/concat/S15.5.4.6_A4_T1.js

// Copyright 2009 the Sputnik authors.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
info: |
    when String.prototype.concat([,[...]]) is called first Call ToString,
    giving it the this value as its argument
es5id: 15.5.4.6_A4_T1
description: Override toString function
---*/

var __instance = {
  toString: function() {
    return "one"
  }
};

__instance.concat = String.prototype.concat;

//////////////////////////////////////////////////////////////////////////////
//CHECK#1
if (__instance.concat("two", x) !== "onetwoundefined") {
  $ERROR('#1: var x; __instance = {toString:function(){return "one"}}; __instance.concat = String.prototype.concat;  __instance.concat("two",x) === "onetwoundefined". Actual: ' + __instance.concat("two", x));
}
//
//////////////////////////////////////////////////////////////////////////////

var x;