test262/test/built-ins/Object/internals/DefineOwnProperty/nan-equivalence.js

88 lines
2.7 KiB
JavaScript

// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-ordinary-object-internal-methods-and-internal-slots-defineownproperty-p-desc
es6id: 9.1.6
description: >
Replaces value field even if they pass in the SameValue algorithm, including
distinct NaN values
info: |
Previously, this method compared the "value" field using the SameValue
algorithm (thereby ignoring distinct NaN values)
---
[[DefineOwnProperty]] (P, Desc)
1. Return ? OrdinaryDefineOwnProperty(O, P, Desc).
9.1.6.1 OrdinaryDefineOwnProperty
1. Let current be ? O.[[GetOwnProperty]](P).
2. Let extensible be O.[[Extensible]].
3. Return ValidateAndApplyPropertyDescriptor(O, P, extensible, Desc,
current).
9.1.6.3 ValidateAndApplyPropertyDescriptor
[...]
7. Else if IsDataDescriptor(current) and IsDataDescriptor(Desc) are both true,
then
a. If current.[[Configurable]] is false and current.[[Writable]] is false,
then
[...]
[...]
9. If O is not undefined, then
a. For each field of Desc that is present, set the corresponding attribute
of the property named P of object O to the value of the field.
10. Return true.
features: [Float64Array, Uint8Array, Uint16Array]
includes: [nans.js]
---*/
var isLittleEndian = new Uint8Array(new Uint16Array([1]).buffer)[0] !== 0;
var float = new Float64Array(1);
var ints = new Uint8Array(float.buffer);
var len = distinctNaNs.length;
function byteValue(value) {
float[0] = value;
var hex = "0123456789ABCDEF";
var s = "";
for (var i = 0; i < 8; ++i) {
var v = ints[isLittleEndian ? 7 - i : i];
s += hex[(v >> 4) & 0xf] + hex[v & 0xf];
}
return s;
}
/**
* Iterate over each pair of distinct NaN values (with replacement). If two or
* more suitable NaN values cannot be identified, the semantics under test
* cannot be verified and this test is expected to pass without evaluating any
* assertions.
*/
for (var idx = 0; idx < len; ++idx) {
for (var jdx = 0; jdx < len; ++jdx) {
// NB: Don't store the distinct NaN values as global variables, because
// global variables are properties of the global object. And in this test
// we want to ensure NaN-valued properties in objects are properly handled,
// so storing NaN values in the (global) object defeats the purpose.
if (byteValue(distinctNaNs[idx]) === byteValue(distinctNaNs[jdx])) {
continue;
}
var subject = {};
subject.prop = distinctNaNs[idx];
subject.prop = distinctNaNs[jdx];
assert.sameValue(
byteValue(subject.prop),
byteValue(distinctNaNs[jdx]),
'Property value was re-set'
);
}
}