src/third_party/mozjs-45/js/src/tests/test262/ch11/11.13/11.13.2/S11.13.2_A4.4_T1.4.js

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

/**
 * The production x += y is the same as x = x + y
 *
 * @path ch11/11.13/11.13.2/S11.13.2_A4.4_T1.4.js
 * @description Type(x) and Type(y) vary between primitive string and String object
 */

//CHECK#1
x = "1";
x += "1";
if (x !== "11") {
  $ERROR('#1: x = "1"; x += "1"; x === "11". Actual: ' + (x));
}

//CHECK#2
x = new String("1");
x += "1";
if (x !== "11") {
  $ERROR('#2: x = new String("1"); x += "1"; x === "11". Actual: ' + (x));
}

//CHECK#3
x = "1";
x += new String("1");
if (x !== "11") {
  $ERROR('#3: x = "1"; x += new String("1"); x === "11". Actual: ' + (x));
}

//CHECK#4
x = new String("1");
x += new String("1");
if (x !== "11") {
  $ERROR('#4: x = new String("1"); x += new String("1"); x === "11". Actual: ' + (x));
}

//CHECK#5
if ("x" + "1" !=="x1") {
  $ERROR('#5: x = "x"; x += "1"; x === "x1". Actual: ' + (x));
}

//CHECK#6
x = "1";
x += "x";
if (x !== "1x") {
  $ERROR('#6: x = "1"; x += "x"; x === "1x". Actual: ' + (x));
}