JSTests/test262/test/language/expressions/addition/S11.6.1_A3.1_T1.3.js

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

/*---
info: |
    If Type(Primitive(x)) is not String and Type(Primitive(y)) is not String,
    then operator x + y returns ToNumber(x) + ToNumber(y)
es5id: 11.6.1_A3.1_T1.3
description: >
    Type(Primitive(x)) and Type(Primitive(y)) vary between Null and
    Undefined
---*/

//CHECK#1
if (isNaN(null + undefined) !== true) {
  $ERROR('#1: null + undefined === Not-a-Number. Actual: ' + (null + undefined));
}

//CHECK#2
if (isNaN(undefined + null) !== true) {
  $ERROR('#2: undefined + null === Not-a-Number. Actual: ' + (undefined + null));
}

//CHECK#3
if (isNaN(undefined + undefined) !== true) {
  $ERROR('#3: undefined + undefined === Not-a-Number. Actual: ' + (undefined + undefined));
}

//CHECK#4
if (null + null !== 0) {
  $ERROR('#4: null + null === 0. Actual: ' + (null + null));
}