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Test Info: Warnings

<?xml version="1.0"?>
<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
<window title="Mozilla Bug 933681"
<!-- test results are displayed in the html:body -->
target="_blank">Mozilla Bug 933681</a>
<!-- test code goes here -->
<script type="application/javascript">
/** Test for ES constructors on Xrayed globals. **/
let global = Cu.getGlobalForObject.bind(Cu);
function checkThrows(f, rgxp, msg) {
try {
ok(false, "Should have thrown: " + msg);
} catch (e) {
ok(true, "Threw as expected: " + msg);
ok(rgxp.test(e), "Message correct: " + e);
var { AppConstants } = SpecialPowers.ChromeUtils.importESModule(
var isNightlyBuild = AppConstants.NIGHTLY_BUILD;
var isReleaseOrBeta = AppConstants.RELEASE_OR_BETA;
let typedArrayClasses = ['Uint8Array', 'Int8Array', 'Uint16Array', 'Int16Array',
'Uint32Array', 'Int32Array', 'Float32Array', 'Float64Array',
let errorObjectClasses = ['Error', 'InternalError', 'EvalError', 'RangeError', 'ReferenceError',
'SyntaxError', 'TypeError', 'URIError', 'AggregateError'];
// A simpleConstructors entry can either be the name of a constructor as a
// string, or an object containing the properties `name`, and `args`.
// In the former case, the constructor is invoked without any args; in the
// latter case, it is invoked with `args` as the arguments list.
let simpleConstructors = ['Object', 'Function', 'Array', 'Boolean', 'Date', 'Number',
'String', 'RegExp', 'ArrayBuffer', 'WeakMap', 'WeakSet', 'Map', 'Set',
{name: 'Promise', args: [function(){}]}];
// All TypedArray constructors can be called with zero arguments.
simpleConstructors = simpleConstructors.concat(typedArrayClasses);
// All Error constructors except AggregateError can be called with zero arguments.
simpleConstructors = simpleConstructors.concat(errorObjectClasses.filter(name => {
return name !== 'AggregateError';
function go() {
window.iwin = document.getElementById('ifr').contentWindow;
/* global iwin */
// Test constructors that can be instantiated with zero arguments, or with
// a fixed set of arguments provided using ``.
for (let c of simpleConstructors) {
var args = [];
if (typeof c === 'object') {
args = c.args;
c =;
ok(iwin[c], "Constructors appear: " + c);
is(iwin[c], Cu.unwaiveXrays(iwin.wrappedJSObject[c]),
"we end up with the appropriate constructor: " + c);
is(Cu.unwaiveXrays(Cu.waiveXrays(new iwin[c](...args)).constructor), iwin[c],
"constructor property is set up right: " + c);
let expectedProto = Cu.isOpaqueWrapper(new iwin[c](...args)) ?
iwin.Object.prototype : iwin[c].prototype;
is(Object.getPrototypeOf(new iwin[c](...args)), expectedProto,
"prototype is correct: " + c);
is(global(new iwin[c](...args)), iwin, "Got the right global: " + c);
// Test Object in more detail.
var num = new iwin.Object(4);
is(Cu.waiveXrays(num).valueOf(), 4, "primitive object construction works");
is(global(num), iwin, "correct global for num");
var obj = new iwin.Object(); = 2;
var withProto = Cu.unwaiveXrays(Cu.waiveXrays(iwin).Object.create(obj));
is(global(withProto), iwin, "correct global for withProto");
is(Cu.waiveXrays(withProto).foo, 2, "Inherits properly");
// Test Function.
var primitiveFun = new iwin.Function('return 2');
is(global(primitiveFun), iwin, "function construction works");
is(primitiveFun(), 2, "basic function works");
var doSetFoo = new iwin.Function('arg', ' = 2;');
is(global(doSetFoo), iwin, "function with args works");
try {
ok(false, "should have thrown while setting property on object");
} catch (e) {
ok(!!/denied/.test(e), "Threw correctly: " + e);
var factoryFun = new iwin.Function('return {foo: 32}');
is(global(factoryFun), iwin, "proper global for factoryFun");
is(factoryFun().foo, 32, "factoryFun invokable");
is(global(factoryFun()), iwin, "minted objects live in the content scope");
testXray('Function', factoryFun, new iwin.Function(), ['length', 'name']);
var echoThis = new iwin.Function('return this;');
echoThis.wrappedJSObject.bind = 42;
var boundEchoThis = echoThis.bind(document);
is(boundEchoThis(), document, "bind() works correctly over Xrays");
is(global(boundEchoThis), window, "bound functions live in the caller's scope");
ok(/return this/.test(echoThis.toSource()), 'toSource works: ' + echoThis.toSource());
ok(/return this/.test(echoThis.toString()), 'toString works: ' + echoThis.toString());
is(iwin.Function.prototype, Object.getPrototypeOf(echoThis), "Function.prototype works for standard classes");
is(echoThis.prototype, undefined, "Function.prototype not visible for non standard constructors");
iwin.eval('var foopyFunction = function namedFoopyFunction(a, b, c) {}');
var foopyFunction = Cu.unwaiveXrays(Cu.waiveXrays(iwin).foopyFunction);
ok(Cu.isXrayWrapper(foopyFunction), "Should be Xrays");
is(, "namedFoopyFunction", ".name works over Xrays");
is(foopyFunction.length, 3, ".length works over Xrays");
ok(Object.getOwnPropertyNames(foopyFunction).includes('length'), "Should list length");
ok(Object.getOwnPropertyNames(foopyFunction).includes('name'), "Should list name");
ok(!Object.getOwnPropertyNames(foopyFunction).includes('prototype'), "Should not list prototype");
ok(Object.getOwnPropertyNames(iwin.Array).includes('prototype'), "Should list prototype for standard constructor");
// Test BoundFunction.
iwin.eval('var boundFoopyFunction = foopyFunction.bind(null, 1)');
var boundFoopyFunction = Cu.unwaiveXrays(Cu.waiveXrays(iwin).boundFoopyFunction);
is(, "bound namedFoopyFunction", "bound .name works over Xrays");
is(boundFoopyFunction.length, 2, "bound .length works over Xrays");
is(JSON.stringify(Object.getOwnPropertyNames(boundFoopyFunction).sort()), '["length","name"]', "Should list length and name");
// Mutate .name, it's just a data property.
iwin.eval('Object.defineProperty(boundFoopyFunction, "name", {value: "foobar", configurable: true, writable: true});');
is(, "foobar", "mutated .name works over Xrays");
iwin.eval(' = 123;');
is(, undefined, "only support string for .name");
is(, undefined, "deleted .name works over Xrays");
// Mutate .length.
iwin.eval('Object.defineProperty(boundFoopyFunction, "length", {value: 456, configurable: true, writable: true});');
is(boundFoopyFunction.length, 456, "mutated .length works over Xrays");
iwin.eval('boundFoopyFunction.length = "bar";');
is(boundFoopyFunction.length, undefined, "only support number for .length");
// Test proxies.
var targetObject = new iwin.Object(); = 9;
var forwardingProxy = new iwin.Proxy(targetObject, new iwin.Object());
is(global(forwardingProxy), iwin, "proxy global correct");
is(Cu.waiveXrays(forwardingProxy).foo, 9, "forwards correctly");
// Test AggregateError.
// AggregateError throws when called without an iterable object as its first argument.
let args = [new iwin.Array()];
ok(iwin.AggregateError, "AggregateError constructor is present");
is(iwin.AggregateError, Cu.unwaiveXrays(iwin.wrappedJSObject.AggregateError),
"we end up with the appropriate AggregateError constructor");
is(Cu.unwaiveXrays(Cu.waiveXrays(new iwin.AggregateError(...args)).constructor), iwin.AggregateError,
"AggregateError constructor property is set up right");
let expectedProto = Cu.isOpaqueWrapper(new iwin.AggregateError(...args)) ?
iwin.Object.prototype : iwin.AggregateError.prototype;
is(Object.getPrototypeOf(new iwin.AggregateError(...args)), expectedProto,
"AggregateError prototype is correct");
is(global(new iwin.AggregateError(...args)), iwin, "Got the right global for AggregateError");
// Test eval.
var toEval = "({a: 2, b: {foo: 'bar'}, f: function() { return window; }})";
is(global(iwin.eval(toEval)), iwin, "eval creates objects in the correct global");
is(iwin.eval(toEval), 'bar', "eval-ed object looks right");
is(Cu.waiveXrays(iwin.eval(toEval)).f(), Cu.waiveXrays(iwin), "evaled function works right");
// Maintain a static list of the properties that are available on each standard
// prototype, so that we make sure to audit any new ones to make sure they're
// Xray-safe.
var gPrototypeProperties = {};
var gConstructorProperties = {};
// Properties which cannot be invoked if callable without potentially
// rendering the object useless.
var gStatefulProperties = {};
function constructorProps(arr) {
// Some props live on all constructors
return arr.concat(["prototype", "length", "name"]);
gPrototypeProperties.Date =
["getTime", "getTimezoneOffset", "getYear", "getFullYear", "getUTCFullYear",
"getMonth", "getUTCMonth", "getDate", "getUTCDate", "getDay", "getUTCDay",
"getHours", "getUTCHours", "getMinutes", "getUTCMinutes", "getSeconds",
"getUTCSeconds", "getMilliseconds", "getUTCMilliseconds", "setTime",
"setYear", "setFullYear", "setUTCFullYear", "setMonth", "setUTCMonth",
"setDate", "setUTCDate", "setHours", "setUTCHours", "setMinutes",
"setUTCMinutes", "setSeconds", "setUTCSeconds", "setMilliseconds",
"setUTCMilliseconds", "toUTCString", "toLocaleString",
"toLocaleDateString", "toLocaleTimeString", "toDateString", "toTimeString",
"toISOString", "toJSON", "toSource", "toString", "valueOf", "constructor",
"toGMTString", Symbol.toPrimitive];
gConstructorProperties.Date = constructorProps(["UTC", "parse", "now"]);
gPrototypeProperties.Object =
["constructor", "toSource", "toString", "toLocaleString", "valueOf",
"hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable",
"__defineGetter__", "__defineSetter__", "__lookupGetter__", "__lookupSetter__",
gConstructorProperties.Object =
constructorProps(["setPrototypeOf", "getOwnPropertyDescriptor", "getOwnPropertyDescriptors",
"keys", "is", "defineProperty", "defineProperties", "create",
"getOwnPropertyNames", "getOwnPropertySymbols",
"preventExtensions", "freeze", "fromEntries", "isFrozen", "seal",
"isSealed", "assign", "getPrototypeOf", "values",
"entries", "isExtensible", "hasOwn", "groupBy"]);
gPrototypeProperties.Array =
["length", "toSource", "toString", "toLocaleString", "join", "reverse", "sort", "push",
"pop", "shift", "unshift", "splice", "concat", "slice", "lastIndexOf", "indexOf",
"includes", "forEach", "map", "reduce", "reduceRight", "filter", "some", "every", "find",
"findIndex", "copyWithin", "fill", Symbol.iterator, Symbol.unscopables, "entries", "keys",
"values", "constructor", "flat", "flatMap", "at", "findLast", "findLastIndex",
"toReversed", "toSorted", "toSpliced", "with"];
gConstructorProperties.Array =
constructorProps(["isArray", "from", "fromAsync", "of", Symbol.species]);
for (let c of typedArrayClasses) {
gPrototypeProperties[c] = ["constructor", "BYTES_PER_ELEMENT"];
gConstructorProperties[c] = constructorProps(["BYTES_PER_ELEMENT"]);
// There is no TypedArray constructor, looks like.
is(window.TypedArray, undefined, "If this ever changes, add to this test!");
for (let c of errorObjectClasses) {
gPrototypeProperties[c] = ["constructor", "name", "message", "stack"];
gConstructorProperties[c] = constructorProps([]);
// toString and toSource only live on the parent proto (Error.prototype).
gPrototypeProperties.Function =
["constructor", "toSource", "toString", "apply", "call", "bind",
"length", "name", "arguments", "caller", Symbol.hasInstance];
gConstructorProperties.Function = constructorProps([])
gPrototypeProperties.RegExp =
["constructor", "toSource", "toString", "compile", "exec", "test",
Symbol.match, Symbol.matchAll, Symbol.replace,, Symbol.split,
"flags", "dotAll", "global", "hasIndices", "ignoreCase", "multiline", "source", "sticky",
"unicode", "unicodeSets"];
gConstructorProperties.RegExp =
constructorProps(["input", "lastMatch", "lastParen",
"leftContext", "rightContext", "$1", "$2", "$3", "$4",
"$5", "$6", "$7", "$8", "$9", "$_", "$&", "$+",
"$`", "$'", Symbol.species])
gPrototypeProperties.Promise =
["constructor", "catch", "then", "finally", Symbol.toStringTag];
gConstructorProperties.Promise =
constructorProps(["resolve", "reject", "all", "allSettled", "any", "race",
"withResolvers", Symbol.species]);
gPrototypeProperties.ArrayBuffer =
["constructor", "byteLength", "detached", "slice", Symbol.toStringTag, "transfer", "transferToFixedLength"];
gConstructorProperties.ArrayBuffer =
constructorProps(["isView", Symbol.species]);
gStatefulProperties.ArrayBuffer = ["transfer", "transferToFixedLength"]
gPrototypeProperties.SharedArrayBuffer = ["constructor", "slice", "byteLength", "detached", Symbol.toStringTag, "transfer", "transferToFixedLength"];
gConstructorProperties.SharedArrayBuffer = constructorProps([Symbol.species]);
gStatefulProperties.SharedArrayBuffer = ["transfer", "transferToFixedLength"]
gPrototypeProperties.Map =
["constructor", "size", Symbol.toStringTag, "get", "has", "set", "delete",
"keys", "values", "clear", "forEach", "entries", Symbol.iterator];
gConstructorProperties.Map =
constructorProps(["groupBy", Symbol.species]);
gPrototypeProperties.Set =
["constructor", "size", Symbol.toStringTag, "has", "add", "delete",
"keys", "values", "clear", "forEach", "entries", Symbol.iterator];
gConstructorProperties.Set =
gPrototypeProperties.WeakMap =
["constructor", Symbol.toStringTag, "get", "has", "set", "delete"];
gConstructorProperties.WeakMap =
gPrototypeProperties.WeakSet =
["constructor", Symbol.toStringTag, "has", "add", "delete"];
gConstructorProperties.WeakSet =
gPrototypeProperties.DataView =
["constructor", "buffer", "byteLength", "byteOffset", Symbol.toStringTag,
"getInt8", "getUint8", "getInt16", "getUint16",
"getInt32", "getUint32", "getFloat32", "getFloat64",
"setInt8", "setUint8", "setInt16", "setUint16",
"setInt32", "setUint32", "setFloat32", "setFloat64",
"getBigInt64", "getBigUint64", "setBigInt64", "setBigUint64"]
gConstructorProperties.DataView = constructorProps([]);
// Sort an array that may contain symbols as well as strings.
function sortProperties(arr) {
function sortKey(prop) {
return typeof prop + ":" + prop.toString();
arr.sort((a, b) => sortKey(a) < sortKey(b) ? -1 : +1);
// Sort all the lists so we don't need to mutate them later (or copy them
// again to sort them).
for (let c of Object.keys(gPrototypeProperties))
for (let c of Object.keys(gConstructorProperties))
function filterOut(array, props) {
return array.filter(p => !props.includes(p));
function isTypedArrayClass(classname) {
return typedArrayClasses.includes(classname);
function propertyIsGetter(obj, name) {
return !!Object.getOwnPropertyDescriptor(obj, name).get;
function testProtoCallables(protoCallables, xray, xrayProto, localProto, callablesExcluded) {
// Handle undefined callablesExcluded.
let dontCall = callablesExcluded ?? [];
for (let name of protoCallables) {
info("Running tests for property: " + name);
// Test both methods and getter properties.
function lookupCallable(obj) {
let desc = null;
do {
desc = Object.getOwnPropertyDescriptor(obj, name);
if (desc) {
obj = Object.getPrototypeOf(obj);
} while (obj);
return desc ? (desc.get || desc.value) : undefined;
ok(xrayProto.hasOwnProperty(name), `proto should have the property '${name}' as own`);
ok(!xray.hasOwnProperty(name), `instance should not have the property '${name}' as own`);
let method = lookupCallable(xrayProto);
is(typeof method, 'function', "Methods from Xrays are functions");
is(global(method), window, "Methods from Xrays are local");
ok(method instanceof Function, "instanceof works on methods from Xrays");
is(lookupCallable(xrayProto), method, "Holder caching works properly");
is(lookupCallable(xray), method, "Proto props resolve on the instance");
let local = lookupCallable(localProto);
is(method.length, local.length, "Function.length identical");
if (!method.length && !dontCall.includes(name)) {
is( + "", + "",
"Xray and local method results stringify identically");
// If invoking this method returns something non-Xrayable (opaque), the
// stringification is going to return [object Object].
// This happens for set[@@iterator] and other Iterator objects.
let callable = lookupCallable(xray.wrappedJSObject);
if (!Cu.isOpaqueWrapper( && callable) {
is( + "", + "",
"Xray and waived method results stringify identically");
function testCtorCallables(ctorCallables, xrayCtor, localCtor) {
for (let name of ctorCallables) {
// Don't try to test Function.prototype, since that is in fact a callable
// but doesn't really do the things we expect callables to do here
// (e.g. it's in the wrong global, since it gets Xrayed itself).
if (name == "prototype" && == "Function") {
info(`Running tests for property: ${}.${name}`);
// Test both methods and getter properties.
function lookupCallable(obj) {
let desc = null;
do {
desc = Object.getOwnPropertyDescriptor(obj, name);
obj = Object.getPrototypeOf(obj);
} while (!desc);
return desc.get || desc.value;
ok(xrayCtor.hasOwnProperty(name), "ctor should have the property as own");
let method = lookupCallable(xrayCtor);
is(typeof method, 'function', "Methods from ctor Xrays are functions");
is(global(method), window, "Methods from ctor Xrays are local");
ok(method instanceof Function,
"instanceof works on methods from ctor Xrays");
is(lookupCallable(xrayCtor), method,
"Holder caching works properly on ctors");
let local = lookupCallable(localCtor);
is(method.length, local.length,
"Function.length identical for method from ctor");
// Don't try to do the return-value check on, since there is
// absolutely no reason it should return the same value each time.
// Also don't try to do the return-value check on Regexp.lastMatch and
// Regexp["$&"] (which are aliases), because they get state off the global
// they live in, as far as I can tell, so testing them over Xrays will be
// wrong: on the Xray they will actaully get the lastMatch of _our_
// global, not the Xrayed one.
if (!method.length &&
!( == "Date" && name == "now") &&
!( == "RegExp" && (name == "lastMatch" || name == "$&"))) {
is( + "", + "",
"Xray and local method results stringify identically on constructors");
is( + "",
lookupCallable(xrayCtor.wrappedJSObject).call(xrayCtor.wrappedJSObject) + "",
"Xray and waived method results stringify identically");
function testXray(classname, xray, xray2, propsToSkip, ctorPropsToSkip = []) {
propsToSkip = propsToSkip || [];
let xrayProto = Object.getPrototypeOf(xray);
let localProto = window[classname].prototype;
let desiredProtoProps = Object.getOwnPropertyNames(localProto).sort();
gPrototypeProperties[classname].filter(id => typeof id === "string").toSource(),
"A property on the " + classname +
" prototype has changed! You need a security audit from an XPConnect peer");
gPrototypeProperties[classname].filter(id => typeof id !== "string").map(uneval).sort().toSource(),
"A symbol-keyed property on the " + classname +
" prototype has been changed! You need a security audit from an XPConnect peer");
let protoProps = filterOut(desiredProtoProps, propsToSkip);
let protoCallables = protoProps.filter(name => propertyIsGetter(localProto, name, classname) ||
typeof localProto[name] == 'function' &&
name != 'constructor');
let callablesExcluded = gStatefulProperties[classname];
ok(!!protoCallables.length, "Need something to test");
is(xrayProto, iwin[classname].prototype, "Xray proto is correct");
is(xrayProto, xray.__proto__, "Proto accessors agree");
var protoProto = classname == "Object" ? null : iwin.Object.prototype;
is(Object.getPrototypeOf(xrayProto), protoProto, "proto proto is correct");
testProtoCallables(protoCallables, xray, xrayProto, localProto, callablesExcluded);
protoProps.toSource(), "getOwnPropertyNames works");
gPrototypeProperties[classname].filter(id => typeof id !== "string" && !propsToSkip.includes(id))
"getOwnPropertySymbols works");
is(xrayProto.constructor, iwin[classname], "constructor property works");
xrayProto.expando = 42;
is(xray.expando, 42, "Xrayed instances see proto expandos");
is(xray2.expando, 42, "Xrayed instances see proto expandos");
// Now test constructors
let localCtor = window[classname];
let xrayCtor = xrayProto.constructor;
// We already checked that this is the same as iwin[classname]
let desiredCtorProps =
gConstructorProperties[classname].filter(id => typeof id === "string").toSource(),
"A property on the " + classname +
" constructor has changed! You need a security audit from an XPConnect peer");
let desiredCtorSymbols =
gConstructorProperties[classname].filter(id => typeof id !== "string").map(uneval).sort().toSource(),
"A symbol-keyed property on the " + classname +
" constructor has been changed! You need a security audit from an XPConnect peer");
let ctorProps = filterOut(desiredCtorProps, ctorPropsToSkip);
let ctorSymbols = filterOut(desiredCtorSymbols,;
let ctorCallables = ctorProps.filter(name => propertyIsGetter(localCtor, name, classname) ||
typeof localCtor[name] == 'function');
testCtorCallables(ctorCallables, xrayCtor, localCtor);
ctorProps.toSource(), "getOwnPropertyNames works on Xrayed ctors");
ctorSymbols.toSource(), "getOwnPropertySymbols works on Xrayed ctors");
// We will need arraysEqual and testArrayIterators both in this global scope
// and in sandboxes.
function arraysEqual(arr1, arr2, reason) {
is(arr1.length, arr2.length, `${reason}; lengths should be equal`)
for (var i = 0; i < arr1.length; ++i) {
if (Array.isArray(arr2[i])) {
arraysEqual(arr1[i], arr2[i], `${reason}; item at index ${i}`);
} else {
is(arr1[i], arr2[i], `${reason}; item at index ${i} should be equal`);
function testArrayIterators(arrayLike, equivalentArray, reason) {
arraysEqual([...arrayLike], equivalentArray, `${reason}; spread operator`);
arraysEqual([...arrayLike.entries()], [...equivalentArray.entries()],
`${reason}; entries`);
arraysEqual([...arrayLike.keys()], [...equivalentArray.keys()],
`${reason}; keys`);
if (arrayLike.values) {
arraysEqual([...arrayLike.values()], equivalentArray,
`${reason}; values`);
var forEachCopy = [];
arrayLike.forEach(function(arg) { forEachCopy.push(arg); });
arraysEqual(forEachCopy, equivalentArray, `${reason}; forEach copy`);
var everyCopy = [];
arrayLike.every(function(arg) { everyCopy.push(arg); return true; });
arraysEqual(everyCopy, equivalentArray, `${reason}; every() copy`);
var filterCopy = [];
var filterResult = arrayLike.filter(function(arg) {
return true;
arraysEqual(filterCopy, equivalentArray, `${reason}; filter copy`);
arraysEqual([...filterResult], equivalentArray, `${reason}; filter result`);
var findCopy = [];
arrayLike.find(function(arg) { findCopy.push(arg); return false; });
arraysEqual(findCopy, equivalentArray, `${reason}; find() copy`);
var findIndexCopy = [];
arrayLike.findIndex(function(arg) { findIndexCopy.push(arg); return false; });
arraysEqual(findIndexCopy, equivalentArray, `${reason}; findIndex() copy`);
var mapCopy = [];
var mapResult = { mapCopy.push(arg); return arg});
arraysEqual(mapCopy, equivalentArray, `${reason}; map() copy`);
arraysEqual([...mapResult], equivalentArray, `${reason}; map() result`);
var reduceCopy = [];
arrayLike.reduce(function(_, arg) { reduceCopy.push(arg); }, 0);
arraysEqual(reduceCopy, equivalentArray, `${reason}; reduce() copy`);
var reduceRightCopy = [];
arrayLike.reduceRight(function(_, arg) { reduceRightCopy.unshift(arg); }, 0);
arraysEqual(reduceRightCopy, equivalentArray, `${reason}; reduceRight() copy`);
var someCopy = [];
arrayLike.some(function(arg) { someCopy.push(arg); return false; });
arraysEqual(someCopy, equivalentArray, `${reason}; some() copy`);
function testDate() {
// toGMTString is handled oddly in the engine. We don't bother to support
// it over Xrays.
let propsToSkip = ['toGMTString'];
testXray('Date', new iwin.Date(), new iwin.Date(), propsToSkip);
// Test the self-hosted toLocaleString.
var d = new iwin.Date();
isnot(d.toLocaleString, Cu.unwaiveXrays(d.wrappedJSObject.toLocaleString), "Different function identities");
is(Cu.getGlobalForObject(d.toLocaleString), window, "Xray global is correct");
is(Cu.getGlobalForObject(d.wrappedJSObject.toLocaleString), iwin, "Underlying global is correct");
is(d.toLocaleString('de-DE'), d.wrappedJSObject.toLocaleString('de-DE'), "Results match");
var uniqueSymbol;
function testObject() {
testXray('Object', Cu.unwaiveXrays(Cu.waiveXrays(iwin).Object.create(new iwin.Object())),
new iwin.Object(), []);
// Construct an object full of tricky things.
let symbolProps = '';
uniqueSymbol = iwin.eval('var uniqueSymbol = Symbol("uniqueSymbol"); uniqueSymbol');
symbolProps = `, [uniqueSymbol]: 43,
[Symbol.for("registrySymbolProp")]: 44`;
var trickyObject =
iwin.eval(`(function() {
var o = new Object({
primitiveProp: 42, objectProp: { foo: 2 },
xoProp: top, hasOwnProperty: 10,
get getterProp() { return 2; },
set setterProp(x) { },
get getterSetterProp() { return 3; },
set getterSetterProp(x) { },
callableProp: function() { },
nonXrayableProp: new Map()[Symbol.iterator]()
Object.defineProperty(o, "nonConfigurableGetterSetterProp",
{ get: function() { return 5; }, set: function() {} });
return o;
function testArray() {
// The |length| property is generally very weird, especially with respect
// to its behavior on the prototype. Array.prototype is actually an Array
// instance, and therefore has a vestigial .length. But we don't want to
// show that over Xrays, and generally want .length to just appear as an
// |own| data property. So we add it to the ignore list here, and check it
// separately.
// |Symbol.unscopables| should in principle be exposed, but it is
// inconvenient (as it's a data property, unsupported by ClassSpec) and
// low value.
let propsToSkip = ['length', Symbol.unscopables];
testXray('Array', new iwin.Array(20), new iwin.Array(), propsToSkip);
let symbolProps = '';
uniqueSymbol = iwin.eval('var uniqueSymbol = Symbol("uniqueSymbol"); uniqueSymbol');
symbolProps = `trickyArray[uniqueSymbol] = 43;
trickyArray[Symbol.for("registrySymbolProp")] = 44;`;
var trickyArray =
iwin.eval(`var trickyArray = [];
trickyArray.primitiveProp = 42;
trickyArray.objectProp = { foo: 2 };
trickyArray.xoProp = top;
trickyArray.hasOwnProperty = 10;
Object.defineProperty(trickyArray, 'getterProp', { get: function() { return 2; }});
Object.defineProperty(trickyArray, 'setterProp', { set: function(x) {}});
Object.defineProperty(trickyArray, 'getterSetterProp', { get: function() { return 3; }, set: function(x) {}, configurable: true});
Object.defineProperty(trickyArray, 'nonConfigurableGetterSetterProp', { get: function() { return 5; }, set: function(x) {}});
trickyArray.callableProp = function() {};
trickyArray.nonXrayableProp = new Map()[Symbol.iterator]();
// Test indexed access.
trickyArray.wrappedJSObject[9] = "some indexed property";
is(trickyArray[9], "some indexed property", "indexed properties work correctly over Xrays");
is(trickyArray.length, 10, "Length works correctly over Xrays");
checkThrows(function() { "use strict"; delete trickyArray.length; }, /config/, "Can't delete non-configurable 'length' property");
delete trickyArray[9];
is(trickyArray[9], undefined, "Delete works correctly over Xrays");
is(trickyArray.wrappedJSObject[9], undefined, "Delete works correctly over Xrays (viewed via waiver)");
is(trickyArray.length, 10, "length doesn't change");
trickyArray[11] = "some other indexed property";
is(trickyArray.length, 12, "length now changes");
is(trickyArray.wrappedJSObject[11], "some other indexed property");
trickyArray.length = 0;
is(trickyArray.length, 0, "Setting length works over Xray");
is(trickyArray[11], undefined, "Setting length truncates over Xray");
Object.defineProperty(trickyArray, 'length', { configurable: false, enumerable: false, writable: false, value: 0 });
trickyArray[1] = "hi";
is(trickyArray.length, 0, "Length remains non-writable");
is(trickyArray[1], undefined, "Frozen length forbids new properties");
is(trickyArray instanceof iwin.Array, true, "instanceof should work across xray wrappers.");
testArrayIterators(new iwin.Array(1, 1, 2, 3, 5), [1, 1, 2, 3, 5]);
// Parts of this function are kind of specific to testing Object, but we factor
// it out so that we can re-use the trickyObject stuff on Arrays.
function testTrickyObject(trickyObject) {
// Make sure it looks right under the hood.
is(trickyObject.wrappedJSObject.getterProp, 2, "Underlying object has getter");
is(Cu.unwaiveXrays(trickyObject.wrappedJSObject.xoProp), top, "Underlying object has xo property");
// Test getOwnPropertyNames.
var expectedNames = ['objectProp', 'primitiveProp'];
if (trickyObject instanceof iwin.Array)
expectedNames.sort().toSource(), "getOwnPropertyNames should be filtered correctly");
var expectedSymbols = [Symbol.for("registrySymbolProp"), uniqueSymbol];
"getOwnPropertySymbols should be filtered correctly");
// Test that cloning uses the Xray view.
var cloned = Cu.cloneInto(trickyObject, this);
expectedNames.sort().toSource(), "structured clone should use the Xray view");
"[]", "structured cloning doesn't clone symbol-keyed properties yet");
// Test iteration and in-place modification. Beware of 'expando', which is the property
// we placed on the xray proto.
var propCount = 0;
for (let prop in trickyObject) {
if (prop == 'primitiveProp')
trickyObject[prop] = trickyObject[prop] - 10;
if (prop != 'expando') {
// eslint-disable-next-line no-self-assign
trickyObject[prop] = trickyObject[prop];
is(propCount, 3, "Should iterate the correct number of times");
// Test Object.keys.
['objectProp', 'primitiveProp'].toSource(), "Object.keys should be filtered correctly");
// Test getOwnPropertyDescriptor.
is(trickyObject.primitiveProp, 32, "primitive prop works");
is(, 2, "object prop works");
is(typeof trickyObject.callableProp, 'undefined', "filtering works correctly");
is(Object.getOwnPropertyDescriptor(trickyObject, 'primitiveProp').value, 32, "getOwnPropertyDescriptor works");
is(Object.getOwnPropertyDescriptor(trickyObject, 'xoProp'), undefined, "filtering works with getOwnPropertyDescriptor");
// Test defineProperty.
trickyObject.primitiveSetByXray = 'fourty two';
is(trickyObject.primitiveSetByXray, 'fourty two', "Can set primitive correctly over Xray (ready via Xray)");
is(trickyObject.wrappedJSObject.primitiveSetByXray, 'fourty two', "Can set primitive correctly over Xray (ready via Waiver)");
var newContentObject = iwin.eval('new Object({prop: 99, get getterProp() { return 2; }})');
trickyObject.objectSetByXray = newContentObject;
is(trickyObject.objectSetByXray.prop, 99, "Can set object correctly over Xray (ready via Xray)");
is(trickyObject.wrappedJSObject.objectSetByXray.prop, 99, "Can set object correctly over Xray (ready via Waiver)");
checkThrows(function() { trickyObject.rejectedProp = {foo: 33}}, /cross-origin object/,
"Should reject privileged object property definition");
// Test JSON.stringify.
var jsonStr = JSON.stringify(newContentObject);
ok(/prop/.test(jsonStr), "JSON stringification should work: " + jsonStr);
// Test deletion.
delete newContentObject.prop;
ok(!newContentObject.hasOwnProperty('prop'), "Deletion should work");
ok(!newContentObject.wrappedJSObject.hasOwnProperty('prop'), "Deletion should forward");
delete newContentObject.getterProp;
ok(newContentObject.wrappedJSObject.hasOwnProperty('getterProp'), "Deletion be no-op for filtered property");
// We should be able to overwrite an existing accessor prop and convert it
// to a value prop.
is(trickyObject.wrappedJSObject.getterSetterProp, 3, "Underlying object has getter");
is(trickyObject.getterSetterProp, undefined, "Filtering properly over Xray");
trickyObject.getterSetterProp = 'redefined';
is(trickyObject.getterSetterProp, 'redefined', "Redefinition works");
is(trickyObject.wrappedJSObject.getterSetterProp, 'redefined', "Redefinition forwards");
// We should NOT be able to overwrite an existing non-configurable accessor
// prop, though.
is(trickyObject.wrappedJSObject.nonConfigurableGetterSetterProp, 5,
"Underlying object has getter");
is(trickyObject.nonConfigurableGetterSetterProp, undefined,
"Filtering properly over Xray here too");
is((trickyObject.nonConfigurableGetterSetterProp = 'redefined'), 'redefined',
"Assigning to non-configurable prop should fail silently in non-strict mode");
checkThrows(function() {
"use strict";
trickyObject.nonConfigurableGetterSetterProp = 'redefined';
}, /config/, "Should throw when redefining non-configurable prop in strict mode");
is(trickyObject.nonConfigurableGetterSetterProp, undefined,
"Redefinition should have failed");
is(trickyObject.wrappedJSObject.nonConfigurableGetterSetterProp, 5,
"Redefinition really should have failed");
checkThrows(function() { trickyObject.hasOwnProperty = 33; }, /shadow/,
"Should reject shadowing of pre-existing inherited properties over Xrays");
checkThrows(function() { Object.defineProperty(trickyObject, 'rejectedProp', { get() { return undefined; }}); },
/accessor property/, "Should reject accessor property definition");
function testTypedArrays() {
// We don't invoke testXray with %TypedArray%, because that function isn't
// set up to deal with "anonymous" dependent classes (that is, classes not
// visible as a global property, which %TypedArray% is not), and fixing it
// up is more trouble than it's worth.
var typedArrayProto = Object.getPrototypeOf(Int8Array.prototype);
var desiredInheritedProps = Object.getOwnPropertyNames(typedArrayProto).sort();
var inheritedProps =
filterOut(desiredInheritedProps, ["BYTES_PER_ELEMENT", "constructor"]);
var inheritedCallables =
inheritedProps.filter(name => (propertyIsGetter(typedArrayProto, name) ||
typeof typedArrayProto[name] === "function") &&
name !== "constructor");
for (let c of typedArrayClasses) {
var t = new iwin[c](10);
checkThrows(function() { t[2]; }, /performant/, "direct property-wise reading of typed arrays forbidden over Xrays");
checkThrows(function() { t[2] = 3; }, /performant/, "direct property-wise writing of typed arrays forbidden over Xrays");
var wesb = new Cu.Sandbox([iwin], {isWebExtensionContentScript: true});
wesb.t = t;
wesb.eval('t[2] = 3');
is(wesb.eval('t.wrappedJSObject[2]'), 3, "direct property-wise writing of typed arrays allowed for WebExtension content scripts");
is(wesb.eval('t[2]'), 3, "direct property-wise reading and writing of typed arrays allowed for WebExtensions content scripts");
t.wrappedJSObject[2] = 3;
is(t.wrappedJSObject[2], 3, "accessing elements over waivers works");
t.wrappedJSObject.expando = 'hi';
is(t.wrappedJSObject.expando, 'hi', "access expandos over waivers works");
is(Cu.cloneInto(t, window)[2], 3, "cloneInto works");
is(Cu.cloneInto(t, window).expando, undefined, "cloneInto does not copy expandos");
'["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]',
"Only indexed properties visible over Xrays");
Object.defineProperty(t.wrappedJSObject, 'length', {value: 42});
is(t.wrappedJSObject.length, 42, "Set tricky expando")
is(t.length, 10, "Length accessor works over Xrays")
is(t.byteLength, t.length * window[c].prototype.BYTES_PER_ELEMENT, "byteLength accessor works over Xrays")
// Can create TypedArray from content ArrayBuffer
var buffer = new iwin.ArrayBuffer(8);
new window[c](buffer);
var xray = new iwin[c](0);
var xrayTypedArrayProto = Object.getPrototypeOf(Object.getPrototypeOf(xray));
testProtoCallables(inheritedCallables, new iwin[c](0), xrayTypedArrayProto, typedArrayProto);
// When testing iterators, make sure to do so from inside our web
// extension sandbox, since from chrome we can't poke their indices. Note
// that we have to actually recreate our functions that touch typed array
// indices inside the sandbox, not just export them, because otherwise
// they'll just run with our principal anyway.
// But we do want to export is(), since we want ours called.
Cu.exportFunction(is, wesb,
{ defineAs: "is" });
wesb.eval('testArrayIterators(t, [0, 0, 3, 0, 0, 0, 0, 0, 0, 0])');
function testErrorObjects() {
// We only invoke testXray with Error, because that function isn't set up
// to deal with dependent classes and fixing it up is more trouble than
// it's worth.
testXray('Error', new iwin.Error('some error message'), new iwin.Error());
// Make sure that the dependent classes have their prototypes set up correctly.
for (let c of errorObjectClasses.filter(x => x != "Error")) {
var args = ['some message'];
if (c === 'AggregateError') {
// AggregateError's first argument is the list of aggregated errors.
args.unshift(new iwin.Array('error 1', 'error 2'));
var e = new iwin[c](...args);
is(Object.getPrototypeOf(e).name, c, "Prototype has correct name");
is(Object.getPrototypeOf(Object.getPrototypeOf(e)), iwin.Error.prototype, "Dependent prototype set up correctly");
is(, c, "Exception name inherited correctly");
function testProperty(name, criterion, goodReplacement, faultyReplacement) {
ok(criterion(e[name]), name + " property is correct: " + e[name]);
e.wrappedJSObject[name] = goodReplacement;
is(e[name], goodReplacement, name + " property ok after replacement: " + goodReplacement);
e.wrappedJSObject[name] = faultyReplacement;
is(e[name], name == 'message' ? "" : undefined, name + " property skipped after suspicious replacement");
testProperty('message', x => x == 'some message', 'some other message', 42);
testProperty('fileName', x => x == '', 'otherFilename.html', new iwin.Object());
testProperty('columnNumber', x => x == 1, 99, 99.5);
testProperty('lineNumber', x => x == 0, 50, 'foo');
if (c === 'AggregateError') {
let {errors} = e;
is(errors.length, 2, "errors property has the correct length");
is(errors[0], 'error 1', "errors[0] has the correct value");
is(errors[1], 'error 2', "errors[1] has the correct value");
e.wrappedJSObject.errors = 42;
is(e.wrappedJSObject.errors, 42, "errors is a plain data property");
is(e.errors, 42, "visible over Xrays");
// Note - an Exception newed via Xrays is going to have an empty stack given the
// current semantics and implementation. This tests the current behavior, but that
// may change in bug 1036527 or similar.
// Furthermore, xrays should always return an error's original stack, and
// not overwrite it.
var stack = e.stack;
ok(/^\s*$/.test(stack), "stack property should be correct");
e.wrappedJSObject.stack = "not a stack";
is(e.stack, stack, "Xrays should never get an overwritten stack property.");
// Test the .cause property is correctly handled, too.
if (isNightlyBuild) {
let cause = 'error cause';
let options = new iwin.Object();
options.cause = cause;
let e = new iwin[c](...args);
is(e.cause, cause);
e.wrappedJSObject.cause = 42;
is(e.wrappedJSObject.cause, 42, "cause is a plain data property");
is(e.cause, 42, "visible over Xrays");
function testRegExp() {
// RegExp statics are very weird, and in particular RegExp has static
// properties that have to do with the last regexp execution in the global.
// Xraying those makes no sense, so we just skip constructor properties for
// RegExp xrays.
// RegExp[@@species] is affected by above skip, but we don't fix it until
// compelling use-case appears, as supporting RegExp[@@species] while
// skipping other static properties makes things complicated.
let ctorPropsToSkip = ["input", "lastMatch", "lastParen",
"leftContext", "rightContext", "$1", "$2", "$3",
"$4", "$5", "$6", "$7", "$8", "$9", "$_", "$&",
"$+", "$`", "$'", Symbol.species];
testXray('RegExp', new iwin.RegExp('foo'), new iwin.RegExp(), [],
// Test the self-hosted |flags| property, toString, and toSource.
for (var flags of ["", "g", "i", "m", "y", "gimy"]) {
var re = new iwin.RegExp("foo", flags);
is(re.flags, re.wrappedJSObject.flags, "Results match");
isnot(re.toString, Cu.unwaiveXrays(re.wrappedJSObject.toString), "Different function identities");
is(Cu.getGlobalForObject(re.toString), window, "Xray global is correct");
is(Cu.getGlobalForObject(re.wrappedJSObject.toString), iwin, "Underlying global is correct");
is(re.toString(), re.wrappedJSObject.toString(), "Results match");
isnot(re.toSource, Cu.unwaiveXrays(re.wrappedJSObject.toSource), "Different function identities");
is(Cu.getGlobalForObject(re.toSource), window, "Xray global is correct");
if (re.wrappedJSObject.toSource) {
is(Cu.getGlobalForObject(re.wrappedJSObject.toSource), iwin, "Underlying global is correct");
is(re.toSource(), re.wrappedJSObject.toSource(), "Results match");
// Test with modified flags accessors
var props = ["global", "ignoreCase", "multiline", "sticky", "source", "unicode"];
var origDescs = {};
for (var prop of props) {
origDescs[prop] = Object.getOwnPropertyDescriptor(RegExp.prototype, prop);
Object.defineProperty(RegExp.prototype, prop, {
get: function() {
throw new Error("modified accessor is called");
try {
is(re.flags, flags, "Unmodified flags accessors are called");
is(re.toString(), "/foo/" + flags, "Unmodified flags and source accessors are called");
is(re.toSource(), "/foo/" + flags, "Unmodified flags and source accessors are called");
} finally {
for (var prop of props) {
Object.defineProperty(RegExp.prototype, prop, origDescs[prop]);
// Note: this is a small set of basic tests. More in-depth tests are located
// in test_promise_xrays.html.
function testPromise() {
testXray('Promise', new iwin.Promise(function(){}), new iwin.Promise(function(){}));
// Test catch and then.
var pr = new iwin.Promise(function(){});
isnot(pr.catch, Cu.unwaiveXrays(pr.wrappedJSObject.catch), "Different function identities");
is(Cu.getGlobalForObject(pr.catch), window, "Xray global is correct");
is(Cu.getGlobalForObject(pr.wrappedJSObject.catch), iwin, "Underlying global is correct");
isnot(pr.then, Cu.unwaiveXrays(pr.wrappedJSObject.then), "Different function identities");
is(Cu.getGlobalForObject(pr.then), window, "Xray global is correct");
is(Cu.getGlobalForObject(pr.wrappedJSObject.then), iwin, "Underlying global is correct");
function testArrayBuffer() {
let constructors = ['ArrayBuffer'];
for (const c of constructors) {
testXray(c, new iwin[c](0), new iwin[c](12));
var t = new iwin[c](12);
is(t.byteLength, 12, `${c} byteLength is correct`);
is(t.slice(4).byteLength, 8, `${c} byteLength is correct after slicing`);
is(Cu.getGlobalForObject(t.slice(4)), iwin, "Slice results lives in the target compartment");
is(Object.getPrototypeOf(t.slice(4)), iwin[c].prototype, "Slice results proto lives in target compartment")
var i32Array = new Int32Array(t);
// i32Array is going to be created in the buffer's target compartment,
// but usually this is unobservable, because the proto is set to
// the current compartment's prototype.
// However Xrays ignore the object's proto and claim its proto is
// the default proto for that class in the relevant compartment,
// so see through this proto hack.
todo_is(Object.getPrototypeOf(i32Array), Int32Array.prototype, "Int32Array has correct proto");
is(i32Array.length, 3, `Int32Array created from Xray ${c} has the correct length`);
is(i32Array.buffer, t, "Int32Array has the correct buffer that we passed in");
i32Array = new iwin.Int32Array(t);
is(Object.getPrototypeOf(i32Array), iwin.Int32Array.prototype, "Xray Int32Array has correct proto");
is(i32Array.length, 3, `Xray Int32Array created from Xray ${c} has the correct length`);
is(i32Array.buffer, t, "Xray Int32Array has the correct buffer that we passed in");
t = (new iwin.Int32Array(2)).buffer;
is(t.byteLength, 8, `Can access ${c} returned by buffer property`);
function testMap() {
testXray('Map', new iwin.Map(), new iwin.Map());
var t = iwin.eval(`new Map([[1, "a"], [null, "b"]])`);
is(t.size, 2, "Map size is correct");
is(t.get(1), "a", "Key 1 has the correct value");
is(t.get(null), "b", "Key null has the correct value");
is(t.has(1), true, "Has Key 1");
is(t.set(3, 5).get(3), 5, "Correctly sets key");
is(t.delete(null), true, "Key null can be deleted");
let values = [];
t.forEach((value) => values.push(value));
is(values.toString(), "a,5", "forEach enumerates values correctly");
is(t.size, 0, "Map is empty after calling clear");
function testSet() {
testXray('Set', new iwin.Set(), new iwin.Set());
var t = iwin.eval(`new Set([1, null])`);
is(t.size, 2, "Set size is correct");
is(t.has(1), true, "Contains 1");
is(t.has(null), true, "Contains null");
is(t.add(5).has(5), true, "Can add value to set");
is(t.delete(null), true, "Value null can be deleted");
let values = [];
t.forEach(value => values.push(value));
is(values.toString(), "1,5", "forEach enumerates values correctly");
is(t.size, 0, "Set is empty after calling clear");
function testWeakMap() {
testXray('WeakMap', new iwin.WeakMap(), new iwin.WeakMap());
var key1 = iwin.eval(`var key1 = {}; key1`);
var key2 = iwin.eval(`var key2 = []; key2`);
var key3 = iwin.eval(`var key3 = /a/; key3`);
var key4 = {};
var key5 = [];
var t = iwin.eval(`new WeakMap([[key1, "a"], [key2, "b"]])`);
is(t.get(key1), "a", "key1 has the correct value");
is(t.get(key2), "b", "key2 has the correct value");
is(t.has(key1), true, "Has key1");
is(t.has(key3), false, "Doesn't have key3");
is(t.has(key5), false, "Doesn't have key5");
is(t.set(key4, 5).get(key4), 5, "Correctly sets key");
is(t.get(key1), "a", "key1 has the correct value after modification");
is(t.get(key2), "b", "key2 has the correct value after modification");
is(t.delete(key1), true, "key1 can be deleted");
is(t.delete(key2), true, "key2 can be deleted");
is(t.delete(key3), false, "key3 cannot be deleted");
is(t.delete(key4), true, "key4 can be deleted");
is(t.delete(key5), false, "key5 cannot be deleted");
function testWeakSet() {
testXray('WeakSet', new iwin.WeakSet(), new iwin.WeakSet());
var key1 = iwin.eval(`var key1 = {}; key1`);
var key2 = iwin.eval(`var key2 = []; key2`);
var key3 = iwin.eval(`var key3 = /a/; key3`);
var key4 = {};
var key5 = [];
var t = iwin.eval(`new WeakSet([key1, key2])`);
is(t.has(key1), true, "Has key1");
is(t.has(key2), true, "Has key2");
is(t.has(key3), false, "Doesn't have key3");
is(t.has(key5), false, "Doesn't have key5");
is(t.add(key4, 5).has(key4), true, "Can add value to set");
is(t.delete(key1), true, "key1 can be deleted");
is(t.delete(key2), true, "key2 can be deleted");
is(t.delete(key3), false, "key3 cannot be deleted");
is(t.delete(key4), true, "key4 can be deleted");
is(t.delete(key5), false, "key5 cannot be deleted");
function testProxy() {
let ProxyCtor = iwin.Proxy;
["length", "name"].sort().toSource(),
"Xrayed Proxy constructor should not have any properties");
is(ProxyCtor.prototype, undefined, "Proxy.prototype should not be set");
// Proxy.revocable can safely be exposed, but it is not.
// Until it is supported, check that the property is not set.
is(ProxyCtor.revocable, undefined, "Proxy.reflect is not set");
function testDataView() {
testXray('DataView', new iwin.DataView(new iwin.ArrayBuffer(4)),
new iwin.DataView(new iwin.ArrayBuffer(8)));
const versions = [() => iwin.eval(`new DataView(new ArrayBuffer(8))`),
() => new DataView(new iwin.ArrayBuffer(8))];
for (const constructor of versions) {
let t = constructor();
is(t.byteLength, 8, `byteLength correct for "${constructor}"`);
is(t.byteOffset, 0, `byteOffset correct for "${constructor}"`);
is(t.buffer.byteLength, 8, `buffer works for "${constructor}"`);
const get = ["getInt8", "getUint8", "getInt16", "getUint16",
"getInt32", "getUint32", "getFloat32", "getFloat64"];
const set = ["setInt8", "setUint8", "setInt16", "setUint16",
"setInt32", "setUint32", "setFloat32", "setFloat64"];
for (const f of get) {
let x = t[f](0);
is(x, 0, `${f} is 0 for "${constructor}"`);
is(typeof x, 'number', `typeof ${f} is number for "${constructor}"`);
for (const f of ["getBigInt64", "getBigUint64"]) {
let x = t[f](0);
is(x, BigInt(0), `${f} is 0n for "${constructor}"`);
is(typeof x, 'bigint', `typeof ${f} is bigint for "${constructor}"`);
for (let i = 0; i < set.length; i++) {
t[set[i]](0, 13);
is(t[get[i]](0), 13, `${get[i]}(0) afer ${set[i]}(0, 13) is 13 for "${constructor}"`);
for (const k of ["BigInt64", "BigUint64"]) {
t["set" + k](0, BigInt(13));
is(t["get" + k](0), BigInt(13), `get${k}(0) afer set${k}(0, 13n) is 13n for "${constructor}"`);
function testNumber() {
// We don't actually support Xrays to Number yet. This is testing
// that case. If we add such support, we might have to start
// using a different non-Xrayed class here, if we can find one.
let xrayCtor = iwin.Number;
Object.getOwnPropertyNames(function() {}).sort().toSource(),
"We should not have any static properties on a non-Xrayable constructor");
is(xrayCtor.noSuchProperty, undefined,
"Where did our noSuchProperty property come from?");