/*global self*//*jshint latedef: nofunc*//* Documentation: https://web-platform-tests.org/writing-tests/testharness-api.html * (../docs/_writing-tests/testharness-api.md) */(function (global_scope){    // default timeout is 10 seconds, test can override if needed    var settings = {        output:true,        harness_timeout:{            "normal":10000,            "long":60000        },        test_timeout:null,        message_events: ["start", "test_state", "result", "completion"],        debug: false,    };    var xhtml_ns = "http://www.w3.org/1999/xhtml";    /*     * TestEnvironment is an abstraction for the environment in which the test     * harness is used. Each implementation of a test environment has to provide     * the following interface:     *     * interface TestEnvironment {     *   // Invoked after the global 'tests' object has been created and it's     *   // safe to call add_*_callback() to register event handlers.     *   void on_tests_ready();     *     *   // Invoked after setup() has been called to notify the test environment     *   // of changes to the test harness properties.     *   void on_new_harness_properties(object properties);     *     *   // Should return a new unique default test name.     *   DOMString next_default_test_name();     *     *   // Should return the test harness timeout duration in milliseconds.     *   float test_timeout();     * };     */    /*     * A test environment with a DOM. The global object is 'window'. By default     * test results are displayed in a table. Any parent windows receive     * callbacks or messages via postMessage() when test events occur. See     * apisample11.html and apisample12.html.     */    function WindowTestEnvironment() {        this.name_counter = 0;        this.window_cache = null;        this.output_handler = null;        this.all_loaded = false;        var this_obj = this;        this.message_events = [];        this.dispatched_messages = [];        this.message_functions = {            start: [add_start_callback, remove_start_callback,                    function (properties) {                        this_obj._dispatch("start_callback", [properties],                                           {type: "start", properties: properties});                    }],            test_state: [add_test_state_callback, remove_test_state_callback,                         function(test) {                             this_obj._dispatch("test_state_callback", [test],                                                {type: "test_state",                                                 test: test.structured_clone()});                         }],            result: [add_result_callback, remove_result_callback,                     function (test) {                         this_obj.output_handler.show_status();                         this_obj._dispatch("result_callback", [test],                                            {type: "result",                                             test: test.structured_clone()});                     }],            completion: [add_completion_callback, remove_completion_callback,                         function (tests, harness_status, asserts) {                             var cloned_tests = map(tests, function(test) {                                 return test.structured_clone();                             });                             this_obj._dispatch("completion_callback", [tests, harness_status],                                                {type: "complete",                                                 tests: cloned_tests,                                                 status: harness_status.structured_clone(),                                                 asserts: asserts.map(assert => assert.structured_clone())});                         }]        }        on_event(window, 'load', function() {            this_obj.all_loaded = true;        });        on_event(window, 'message', function(event) {            if (event.data && event.data.type === "getmessages" && event.source) {                // A window can post "getmessages" to receive a duplicate of every                // message posted by this environment so far. This allows subscribers                // from fetch_tests_from_window to 'catch up' to the current state of                // this environment.                for (var i = 0; i < this_obj.dispatched_messages.length; ++i)                {                    event.source.postMessage(this_obj.dispatched_messages[i], "*");                }            }        });    }    WindowTestEnvironment.prototype._dispatch = function(selector, callback_args, message_arg) {        this.dispatched_messages.push(message_arg);        this._forEach_windows(                function(w, same_origin) {                    if (same_origin) {                        try {                            var has_selector = selector in w;                        } catch(e) {                            // If document.domain was set at some point same_origin can be                            // wrong and the above will fail.                            has_selector = false;                        }                        if (has_selector) {                            try {                                w[selector].apply(undefined, callback_args);                            } catch (e) {}                        }                    }                    if (w !== self) {                        w.postMessage(message_arg, "*");                    }                });    };    WindowTestEnvironment.prototype._forEach_windows = function(callback) {        // Iterate over the windows [self ... top, opener]. The callback is passed        // two objects, the first one is the window object itself, the second one        // is a boolean indicating whether or not it's on the same origin as the        // current window.        var cache = this.window_cache;        if (!cache) {            cache = [[self, true]];            var w = self;            var i = 0;            var so;            while (w != w.parent) {                w = w.parent;                so = is_same_origin(w);                cache.push([w, so]);                i++;            }            w = window.opener;            if (w) {                cache.push([w, is_same_origin(w)]);            }            this.window_cache = cache;        }        forEach(cache,                function(a) {                    callback.apply(null, a);                });    };    WindowTestEnvironment.prototype.on_tests_ready = function() {        var output = new Output();        this.output_handler = output;        var this_obj = this;        add_start_callback(function (properties) {            this_obj.output_handler.init(properties);        });        add_test_state_callback(function(test) {            this_obj.output_handler.show_status();        });        add_result_callback(function (test) {            this_obj.output_handler.show_status();        });        add_completion_callback(function (tests, harness_status, asserts_run) {            this_obj.output_handler.show_results(tests, harness_status, asserts_run);        });        this.setup_messages(settings.message_events);    };    WindowTestEnvironment.prototype.setup_messages = function(new_events) {        var this_obj = this;        forEach(settings.message_events, function(x) {            var current_dispatch = this_obj.message_events.indexOf(x) !== -1;            var new_dispatch = new_events.indexOf(x) !== -1;            if (!current_dispatch && new_dispatch) {                this_obj.message_functions[x][0](this_obj.message_functions[x][2]);            } else if (current_dispatch && !new_dispatch) {                this_obj.message_functions[x][1](this_obj.message_functions[x][2]);            }        });        this.message_events = new_events;    }    WindowTestEnvironment.prototype.next_default_test_name = function() {        var suffix = this.name_counter > 0 ? " " + this.name_counter : "";        this.name_counter++;        return get_title() + suffix;    };    WindowTestEnvironment.prototype.on_new_harness_properties = function(properties) {        this.output_handler.setup(properties);        if (properties.hasOwnProperty("message_events")) {            this.setup_messages(properties.message_events);        }    };    WindowTestEnvironment.prototype.add_on_loaded_callback = function(callback) {        on_event(window, 'load', callback);    };    WindowTestEnvironment.prototype.test_timeout = function() {        var metas = document.getElementsByTagName("meta");        for (var i = 0; i < metas.length; i++) {            if (metas[i].name == "timeout") {                if (metas[i].content == "long") {                    return settings.harness_timeout.long;                }                break;            }        }        return settings.harness_timeout.normal;    };    /*     * Base TestEnvironment implementation for a generic web worker.     *     * Workers accumulate test results. One or more clients can connect and     * retrieve results from a worker at any time.     *     * WorkerTestEnvironment supports communicating with a client via a     * MessagePort.  The mechanism for determining the appropriate MessagePort     * for communicating with a client depends on the type of worker and is     * implemented by the various specializations of WorkerTestEnvironment     * below.     *     * A client document using testharness can use fetch_tests_from_worker() to     * retrieve results from a worker. See apisample16.html.     */    function WorkerTestEnvironment() {        this.name_counter = 0;        this.all_loaded = true;        this.message_list = [];        this.message_ports = [];    }    WorkerTestEnvironment.prototype._dispatch = function(message) {        this.message_list.push(message);        for (var i = 0; i < this.message_ports.length; ++i)        {            this.message_ports[i].postMessage(message);        }    };    // The only requirement is that port has a postMessage() method. It doesn't    // have to be an instance of a MessagePort, and often isn't.    WorkerTestEnvironment.prototype._add_message_port = function(port) {        this.message_ports.push(port);        for (var i = 0; i < this.message_list.length; ++i)        {            port.postMessage(this.message_list[i]);        }    };    WorkerTestEnvironment.prototype.next_default_test_name = function() {        var suffix = this.name_counter > 0 ? " " + this.name_counter : "";        this.name_counter++;        return get_title() + suffix;    };    WorkerTestEnvironment.prototype.on_new_harness_properties = function() {};    WorkerTestEnvironment.prototype.on_tests_ready = function() {        var this_obj = this;        add_start_callback(                function(properties) {                    this_obj._dispatch({                        type: "start",                        properties: properties,                    });                });        add_test_state_callback(                function(test) {                    this_obj._dispatch({                        type: "test_state",                        test: test.structured_clone()                    });                });        add_result_callback(                function(test) {                    this_obj._dispatch({                        type: "result",                        test: test.structured_clone()                    });                });        add_completion_callback(                function(tests, harness_status, asserts) {                    this_obj._dispatch({                        type: "complete",                        tests: map(tests,                            function(test) {                                return test.structured_clone();                            }),                        status: harness_status.structured_clone(),                        asserts: asserts.map(assert => assert.structured_clone()),                    });                });    };    WorkerTestEnvironment.prototype.add_on_loaded_callback = function() {};    WorkerTestEnvironment.prototype.test_timeout = function() {        // Tests running in a worker don't have a default timeout. I.e. all        // worker tests behave as if settings.explicit_timeout is true.        return null;    };    /*     * Dedicated web workers.     * https://html.spec.whatwg.org/multipage/workers.html#dedicatedworkerglobalscope     *     * This class is used as the test_environment when testharness is running     * inside a dedicated worker.     */    function DedicatedWorkerTestEnvironment() {        WorkerTestEnvironment.call(this);        // self is an instance of DedicatedWorkerGlobalScope which exposes        // a postMessage() method for communicating via the message channel        // established when the worker is created.        this._add_message_port(self);    }    DedicatedWorkerTestEnvironment.prototype = Object.create(WorkerTestEnvironment.prototype);    DedicatedWorkerTestEnvironment.prototype.on_tests_ready = function() {        WorkerTestEnvironment.prototype.on_tests_ready.call(this);        // In the absence of an onload notification, we a require dedicated        // workers to explicitly signal when the tests are done.        tests.wait_for_finish = true;    };    /*     * Shared web workers.     * https://html.spec.whatwg.org/multipage/workers.html#sharedworkerglobalscope     *     * This class is used as the test_environment when testharness is running     * inside a shared web worker.     */    function SharedWorkerTestEnvironment() {        WorkerTestEnvironment.call(this);        var this_obj = this;        // Shared workers receive message ports via the 'onconnect' event for        // each connection.        self.addEventListener("connect",                function(message_event) {                    this_obj._add_message_port(message_event.source);                }, false);    }    SharedWorkerTestEnvironment.prototype = Object.create(WorkerTestEnvironment.prototype);    SharedWorkerTestEnvironment.prototype.on_tests_ready = function() {        WorkerTestEnvironment.prototype.on_tests_ready.call(this);        // In the absence of an onload notification, we a require shared        // workers to explicitly signal when the tests are done.        tests.wait_for_finish = true;    };    /*     * Service workers.     * http://www.w3.org/TR/service-workers/     *     * This class is used as the test_environment when testharness is running     * inside a service worker.     */    function ServiceWorkerTestEnvironment() {        WorkerTestEnvironment.call(this);        this.all_loaded = false;        this.on_loaded_callback = null;        var this_obj = this;        self.addEventListener("message",                function(event) {                    if (event.data && event.data.type && event.data.type === "connect") {                        this_obj._add_message_port(event.source);                    }                }, false);        // The oninstall event is received after the service worker script and        // all imported scripts have been fetched and executed. It's the        // equivalent of an onload event for a document. All tests should have        // been added by the time this event is received, thus it's not        // necessary to wait until the onactivate event. However, tests for        // installed service workers need another event which is equivalent to        // the onload event because oninstall is fired only on installation. The        // onmessage event is used for that purpose since tests using        // testharness.js should ask the result to its service worker by        // PostMessage. If the onmessage event is triggered on the service        // worker's context, that means the worker's script has been evaluated.        on_event(self, "install", on_all_loaded);        on_event(self, "message", on_all_loaded);        function on_all_loaded() {            if (this_obj.all_loaded)                return;            this_obj.all_loaded = true;            if (this_obj.on_loaded_callback) {              this_obj.on_loaded_callback();            }        }    }    ServiceWorkerTestEnvironment.prototype = Object.create(WorkerTestEnvironment.prototype);    ServiceWorkerTestEnvironment.prototype.add_on_loaded_callback = function(callback) {        if (this.all_loaded) {            callback();        } else {            this.on_loaded_callback = callback;        }    };    /*     * Shadow realms.     * https://github.com/tc39/proposal-shadowrealm     *     * This class is used as the test_environment when testharness is running     * inside a shadow realm.     */    function ShadowRealmTestEnvironment() {        WorkerTestEnvironment.call(this);        this.all_loaded = false;        this.on_loaded_callback = null;    }    ShadowRealmTestEnvironment.prototype = Object.create(WorkerTestEnvironment.prototype);    /**     * Signal to the test environment that the tests are ready and the on-loaded     * callback should be run.     *     * Shadow realms are not *really* a DOM context: they have no `onload` or similar     * event for us to use to set up the test environment; so, instead, this method     * is manually triggered from the incubating realm     *     * @param {Function} message_destination - a function that receives JSON-serializable     * data to send to the incubating realm, in the same format as used by RemoteContext     */    ShadowRealmTestEnvironment.prototype.begin = function(message_destination) {        if (this.all_loaded) {            throw new Error("Tried to start a shadow realm test environment after it has already started");        }        var fakeMessagePort = {};        fakeMessagePort.postMessage = message_destination;        this._add_message_port(fakeMessagePort);        this.all_loaded = true;        if (this.on_loaded_callback) {            this.on_loaded_callback();        }    };    ShadowRealmTestEnvironment.prototype.add_on_loaded_callback = function(callback) {        if (this.all_loaded) {            callback();        } else {            this.on_loaded_callback = callback;        }    };    /*     * JavaScript shells.     *     * This class is used as the test_environment when testharness is running     * inside a JavaScript shell.     */    function ShellTestEnvironment() {        this.name_counter = 0;        this.all_loaded = false;        this.on_loaded_callback = null;        Promise.resolve().then(function() {            this.all_loaded = true            if (this.on_loaded_callback) {                this.on_loaded_callback();            }        }.bind(this));        this.message_list = [];        this.message_ports = [];    }    ShellTestEnvironment.prototype.next_default_test_name = function() {        var suffix = this.name_counter > 0 ? " " + this.name_counter : "";        this.name_counter++;        return "Untitled" + suffix;    };    ShellTestEnvironment.prototype.on_new_harness_properties = function() {};    ShellTestEnvironment.prototype.on_tests_ready = function() {};    ShellTestEnvironment.prototype.add_on_loaded_callback = function(callback) {        if (this.all_loaded) {            callback();        } else {            this.on_loaded_callback = callback;        }    };    ShellTestEnvironment.prototype.test_timeout = function() {        // Tests running in a shell don't have a default timeout, so behave as        // if settings.explicit_timeout is true.        return null;    };    function create_test_environment() {        if ('document' in global_scope) {            return new WindowTestEnvironment();        }        if ('DedicatedWorkerGlobalScope' in global_scope &&            global_scope instanceof DedicatedWorkerGlobalScope) {            return new DedicatedWorkerTestEnvironment();        }        if ('SharedWorkerGlobalScope' in global_scope &&            global_scope instanceof SharedWorkerGlobalScope) {            return new SharedWorkerTestEnvironment();        }        if ('ServiceWorkerGlobalScope' in global_scope &&            global_scope instanceof ServiceWorkerGlobalScope) {            return new ServiceWorkerTestEnvironment();        }        if ('WorkerGlobalScope' in global_scope &&            global_scope instanceof WorkerGlobalScope) {            return new DedicatedWorkerTestEnvironment();        }        /* Shadow realm global objects are _ordinary_ objects (i.e. their prototype is         * Object) so we don't have a nice `instanceof` test to use; instead, we         * check if the there is a GLOBAL.isShadowRealm() property         * on the global object. that was set by the test harness when it         * created the ShadowRealm.         */        if (global_scope.GLOBAL && global_scope.GLOBAL.isShadowRealm()) {            return new ShadowRealmTestEnvironment();        }        return new ShellTestEnvironment();    }    var test_environment = create_test_environment();    function is_shared_worker(worker) {        return 'SharedWorker' in global_scope && worker instanceof SharedWorker;    }    function is_service_worker(worker) {        // The worker object may be from another execution context,        // so do not use instanceof here.        return 'ServiceWorker' in global_scope &&            Object.prototype.toString.call(worker) == '[object ServiceWorker]';    }    var seen_func_name = Object.create(null);    function get_test_name(func, name)    {        if (name) {            return name;        }        if (func) {            var func_code = func.toString();            // Try and match with brackets, but fallback to matching without            var arrow = func_code.match(/^\(\)\s*=>\s*(?:{(.*)}\s*|(.*))$/);            // Check for JS line separators            if (arrow !== null && !/[\u000A\u000D\u2028\u2029]/.test(func_code)) {                var trimmed = (arrow[1] !== undefined ? arrow[1] : arrow[2]).trim();                // drop trailing ; if there's no earlier ones                trimmed = trimmed.replace(/^([^;]*)(;\s*)+$/, "$1");                if (trimmed) {                    let name = trimmed;                    if (seen_func_name[trimmed]) {                        // This subtest name already exists, so add a suffix.                        name += " " + seen_func_name[trimmed];                    } else {                        seen_func_name[trimmed] = 0;                    }                    seen_func_name[trimmed] += 1;                    return name;                }            }        }        return test_environment.next_default_test_name();    }    /**     * @callback TestFunction     * @param {Test} test - The test currnetly being run.     * @param {Any[]} args - Additional args to pass to function.     *     */    /**     * Create a synchronous test     *     * @param {TestFunction} func - Test function. This is executed     * immediately. If it returns without error, the test status is     * set to ``PASS``. If it throws an :js:class:`AssertionError`, or     * any other exception, the test status is set to ``FAIL``     * (typically from an `assert` function).     * @param {String} name - Test name. This must be unique in a     * given file and must be invariant between runs.     */    function test(func, name, properties)    {        if (tests.promise_setup_called) {            tests.status.status = tests.status.ERROR;            tests.status.message = '`test` invoked after `promise_setup`';            tests.complete();        }        var test_name = get_test_name(func, name);        var test_obj = new Test(test_name, properties);        var value = test_obj.step(func, test_obj, test_obj);        if (value !== undefined) {            var msg = 'Test named "' + test_name +                '" passed a function to `test` that returned a value.';            try {                if (value && typeof value.then === 'function') {                    msg += ' Consider using `promise_test` instead when ' +                        'using Promises or async/await.';                }            } catch (err) {}            tests.status.status = tests.status.ERROR;            tests.status.message = msg;        }        if (test_obj.phase === test_obj.phases.STARTED) {            test_obj.done();        }    }    /**     * Create an asynchronous test     *     * @param {TestFunction|string} funcOrName - Initial step function     * to call immediately with the test name as an argument (if any),     * or name of the test.     * @param {String} name - Test name (if a test function was     * provided). This must be unique in a given file and must be     * invariant between runs.     * @returns {Test} An object representing the ongoing test.     */    function async_test(func, name, properties)    {        if (tests.promise_setup_called) {            tests.status.status = tests.status.ERROR;            tests.status.message = '`async_test` invoked after `promise_setup`';            tests.complete();        }        if (typeof func !== "function") {            properties = name;            name = func;            func = null;        }        var test_name = get_test_name(func, name);        var test_obj = new Test(test_name, properties);        if (func) {            var value = test_obj.step(func, test_obj, test_obj);            // Test authors sometimes return values to async_test, expecting us            // to handle the value somehow. Make doing so a harness error to be            // clear this is invalid, and point authors to promise_test if it            // may be appropriate.            //            // Note that we only perform this check on the initial function            // passed to async_test, not on any later steps - we haven't seen a            // consistent problem with those (and it's harder to check).            if (value !== undefined) {                var msg = 'Test named "' + test_name +                    '" passed a function to `async_test` that returned a value.';                try {                    if (value && typeof value.then === 'function') {                        msg += ' Consider using `promise_test` instead when ' +                            'using Promises or async/await.';                    }                } catch (err) {}                tests.set_status(tests.status.ERROR, msg);                tests.complete();            }        }        return test_obj;    }    /**     * Create a promise test.     *     * Promise tests are tests which are represented by a promise     * object. If the promise is fulfilled the test passes, if it's     * rejected the test fails, otherwise the test passes.     *     * @param {TestFunction} func - Test function. This must return a     * promise. The test is automatically marked as complete once the     * promise settles.     * @param {String} name - Test name. This must be unique in a     * given file and must be invariant between runs.     */    function promise_test(func, name, properties) {        if (typeof func !== "function") {            properties = name;            name = func;            func = null;        }        var test_name = get_test_name(func, name);        var test = new Test(test_name, properties);        test._is_promise_test = true;        // If there is no promise tests queue make one.        if (!tests.promise_tests) {            tests.promise_tests = Promise.resolve();        }        tests.promise_tests = tests.promise_tests.then(function() {            return new Promise(function(resolve) {                var promise = test.step(func, test, test);                test.step(function() {                    assert(!!promise, "promise_test", null,                           "test body must return a 'thenable' object (received ${value})",                           {value:promise});                    assert(typeof promise.then === "function", "promise_test", null,                           "test body must return a 'thenable' object (received an object with no `then` method)",                           null);                });                // Test authors may use the `step` method within a                // `promise_test` even though this reflects a mixture of                // asynchronous control flow paradigms. The "done" callback                // should be registered prior to the resolution of the                // user-provided Promise to avoid timeouts in cases where the                // Promise does not settle but a `step` function has thrown an                // error.                add_test_done_callback(test, resolve);                Promise.resolve(promise)                    .catch(test.step_func(                        function(value) {                            if (value instanceof AssertionError) {                                throw value;                            }                            assert(false, "promise_test", null,                                   "Unhandled rejection with value: ${value}", {value:value});                        }))                    .then(function() {                        test.done();                    });                });        });    }    /**     * Make a copy of a Promise in the current realm.     *     * @param {Promise} promise the given promise that may be from a different     *                          realm     * @returns {Promise}     *     * An arbitrary promise provided by the caller may have originated     * in another frame that have since navigated away, rendering the     * frame's document inactive. Such a promise cannot be used with     * `await` or Promise.resolve(), as microtasks associated with it     * may be prevented from being run. See `issue     * 5319<https://github.com/whatwg/html/issues/5319>`_ for a     * particular case.     *     * In functions we define here, there is an expectation from the caller     * that the promise is from the current realm, that can always be used with     * `await`, etc. We therefore create a new promise in this realm that     * inherit the value and status from the given promise.     */    function bring_promise_to_current_realm(promise) {        return new Promise(promise.then.bind(promise));    }    /**     * Assert that a Promise is rejected with the right ECMAScript exception.     *     * @param {Test} test - the `Test` to use for the assertion.     * @param {Function} constructor - The expected exception constructor.     * @param {Promise} promise - The promise that's expected to     * reject with the given exception.     * @param {string} [description] Error message to add to assert in case of     *                               failure.     */    function promise_rejects_js(test, constructor, promise, description) {        return bring_promise_to_current_realm(promise)            .then(test.unreached_func("Should have rejected: " + description))            .catch(function(e) {                assert_throws_js_impl(constructor, function() { throw e },                                      description, "promise_rejects_js");            });    }    /**     * Assert that a Promise is rejected with the right DOMException.     *     * For the remaining arguments, there are two ways of calling     * promise_rejects_dom:     *     * 1) If the DOMException is expected to come from the current global, the     * third argument should be the promise expected to reject, and a fourth,     * optional, argument is the assertion description.     *     * 2) If the DOMException is expected to come from some other global, the     * third argument should be the DOMException constructor from that global,     * the fourth argument the promise expected to reject, and the fifth,     * optional, argument the assertion description.     *     * @param {Test} test - the `Test` to use for the assertion.     * @param {number|string} type - See documentation for     * `assert_throws_dom <#assert_throws_dom>`_.     * @param {Function} promiseOrConstructor - Either the constructor     * for the expected exception (if the exception comes from another     * global), or the promise that's expected to reject (if the     * exception comes from the current global).     * @param {Function|string} descriptionOrPromise - Either the     * promise that's expected to reject (if the exception comes from     * another global), or the optional description of the condition     * being tested (if the exception comes from the current global).     * @param {string} [description] - Description of the condition     * being tested (if the exception comes from another global).     *     */    function promise_rejects_dom(test, type, promiseOrConstructor, descriptionOrPromise, maybeDescription) {        let constructor, promise, description;        if (typeof promiseOrConstructor === "function" &&            promiseOrConstructor.name === "DOMException") {            constructor = promiseOrConstructor;            promise = descriptionOrPromise;            description = maybeDescription;        } else {            constructor = self.DOMException;            promise = promiseOrConstructor;            description = descriptionOrPromise;            assert(maybeDescription === undefined,                   "Too many args pased to no-constructor version of promise_rejects_dom");        }        return bring_promise_to_current_realm(promise)            .then(test.unreached_func("Should have rejected: " + description))            .catch(function(e) {                assert_throws_dom_impl(type, function() { throw e }, description,                                       "promise_rejects_dom", constructor);            });    }    /**     * Assert that a Promise is rejected with the provided value.     *     * @param {Test} test - the `Test` to use for the assertion.     * @param {Any} exception - The expected value of the rejected promise.     * @param {Promise} promise - The promise that's expected to     * reject.     * @param {string} [description] Error message to add to assert in case of     *                               failure.     */    function promise_rejects_exactly(test, exception, promise, description) {        return bring_promise_to_current_realm(promise)            .then(test.unreached_func("Should have rejected: " + description))            .catch(function(e) {                assert_throws_exactly_impl(exception, function() { throw e },                                           description, "promise_rejects_exactly");            });    }    /**     * Allow DOM events to be handled using Promises.     *     * This can make it a lot easier to test a very specific series of events,     * including ensuring that unexpected events are not fired at any point.     *     * `EventWatcher` will assert if an event occurs while there is no `wait_for`     * created Promise waiting to be fulfilled, or if the event is of a different type     * to the type currently expected. This ensures that only the events that are     * expected occur, in the correct order, and with the correct timing.     *     * @constructor     * @param {Test} test - The `Test` to use for the assertion.     * @param {EventTarget} watchedNode - The target expected to receive the events.     * @param {string[]} eventTypes - List of events to watch for.     * @param {Promise} timeoutPromise - Promise that will cause the     * test to be set to `TIMEOUT` once fulfilled.     *     */    function EventWatcher(test, watchedNode, eventTypes, timeoutPromise)    {        if (typeof eventTypes == 'string') {            eventTypes = [eventTypes];        }        var waitingFor = null;        // This is null unless we are recording all events, in which case it        // will be an Array object.        var recordedEvents = null;        var eventHandler = test.step_func(function(evt) {            assert_true(!!waitingFor,                        'Not expecting event, but got ' + evt.type + ' event');            assert_equals(evt.type, waitingFor.types[0],                          'Expected ' + waitingFor.types[0] + ' event, but got ' +                          evt.type + ' event instead');            if (Array.isArray(recordedEvents)) {                recordedEvents.push(evt);            }            if (waitingFor.types.length > 1) {                // Pop first event from array                waitingFor.types.shift();                return;            }            // We need to null out waitingFor before calling the resolve function            // since the Promise's resolve handlers may call wait_for() which will            // need to set waitingFor.            var resolveFunc = waitingFor.resolve;            waitingFor = null;            // Likewise, we should reset the state of recordedEvents.            var result = recordedEvents || evt;            recordedEvents = null;            resolveFunc(result);        });        for (var i = 0; i < eventTypes.length; i++) {            watchedNode.addEventListener(eventTypes[i], eventHandler, false);        }        /**         * Returns a Promise that will resolve after the specified event or         * series of events has occurred.         *         * @param {Object} options An optional options object. If the 'record' property         *                 on this object has the value 'all', when the Promise         *                 returned by this function is resolved,  *all* Event         *                 objects that were waited for will be returned as an         *                 array.         *         * @example         * const watcher = new EventWatcher(t, div, [ 'animationstart',         *                                            'animationiteration',         *                                            'animationend' ]);         * return watcher.wait_for([ 'animationstart', 'animationend' ],         *                         { record: 'all' }).then(evts => {         *   assert_equals(evts[0].elapsedTime, 0.0);         *   assert_equals(evts[1].elapsedTime, 2.0);         * });         */        this.wait_for = function(types, options) {            if (waitingFor) {                return Promise.reject('Already waiting for an event or events');            }            if (typeof types == 'string') {                types = [types];            }            if (options && options.record && options.record === 'all') {                recordedEvents = [];            }            return new Promise(function(resolve, reject) {                var timeout = test.step_func(function() {                    // If the timeout fires after the events have been received                    // or during a subsequent call to wait_for, ignore it.                    if (!waitingFor || waitingFor.resolve !== resolve)                        return;                    // This should always fail, otherwise we should have                    // resolved the promise.                    assert_true(waitingFor.types.length == 0,                                'Timed out waiting for ' + waitingFor.types.join(', '));                    var result = recordedEvents;                    recordedEvents = null;                    var resolveFunc = waitingFor.resolve;                    waitingFor = null;                    resolveFunc(result);                });                if (timeoutPromise) {                    timeoutPromise().then(timeout);                }                waitingFor = {                    types: types,                    resolve: resolve,                    reject: reject                };            });        };        /**         * Stop listening for events         */        function stop_watching() {            for (var i = 0; i < eventTypes.length; i++) {                watchedNode.removeEventListener(eventTypes[i], eventHandler, false);            }        };        test._add_cleanup(stop_watching);        return this;    }    expose(EventWatcher, 'EventWatcher');    /**     * @typedef {Object} SettingsObject     * @property {bool} single_test - Use the single-page-test     * mode. In this mode the Document represents a single     * `async_test`. Asserts may be used directly without requiring     * `Test.step` or similar wrappers, and any exceptions set the     * status of the test rather than the status of the harness.     * @property {bool} allow_uncaught_exception - don't treat an     * uncaught exception as an error; needed when e.g. testing the     * `window.onerror` handler.     * @property {boolean} explicit_done - Wait for a call to `done()`     * before declaring all tests complete (this is always true for     * single-page tests).     * @property hide_test_state - hide the test state output while     * the test is running; This is helpful when the output of the test state     * may interfere the test results.     * @property {bool} explicit_timeout - disable file timeout; only     * stop waiting for results when the `timeout()` function is     * called This should typically only be set for manual tests, or     * by a test runner that providees its own timeout mechanism.     * @property {number} timeout_multiplier - Multiplier to apply to     * per-test timeouts. This should only be set by a test runner.     * @property {Document} output_document - The document to which     * results should be logged. By default this is the current     * document but could be an ancestor document in some cases e.g. a     * SVG test loaded in an HTML wrapper     *     */    /**     * Configure the harness     *     * @param {Function|SettingsObject} funcOrProperties - Either a     * setup function to run, or a set of properties. If this is a     * function that function is run synchronously. Any exception in     * the function will set the overall harness status to `ERROR`.     * @param {SettingsObject} maybeProperties - An object containing     * the settings to use, if the first argument is a function.     *     */    function setup(func_or_properties, maybe_properties)    {        var func = null;        var properties = {};        if (arguments.length === 2) {            func = func_or_properties;            properties = maybe_properties;        } else if (func_or_properties instanceof Function) {            func = func_or_properties;        } else {            properties = func_or_properties;        }        tests.setup(func, properties);        test_environment.on_new_harness_properties(properties);    }    /**     * Configure the harness, waiting for a promise to resolve     * before running any `promise_test` tests.     *     * @param {Function} func - Function returning a promise that's     * run synchronously. Promise tests are not run until after this     * function has resolved.     * @param {SettingsObject} [properties] - An object containing     * the harness settings to use.     *     */    function promise_setup(func, properties={})    {        if (typeof func !== "function") {            tests.set_status(tests.status.ERROR,                             "promise_test invoked without a function");            tests.complete();            return;        }        tests.promise_setup_called = true;        if (!tests.promise_tests) {            tests.promise_tests = Promise.resolve();        }        tests.promise_tests = tests.promise_tests            .then(function()                  {                      var result;                      tests.setup(null, properties);                      result = func();                      test_environment.on_new_harness_properties(properties);                      if (!result || typeof result.then !== "function") {                          throw "Non-thenable returned by function passed to `promise_setup`";                      }                      return result;                  })            .catch(function(e)                   {                       tests.set_status(tests.status.ERROR,                                        String(e),                                        e && e.stack);                       tests.complete();                   });    }    /**     * Mark test loading as complete.     *     * Typically this function is called implicitly on page load; it's     * only necessary for users to call this when either the     * ``explicit_done`` or ``single_page`` properties have been set     * via the :js:func:`setup` function.     *     * For single page tests this marks the test as complete and sets its status.     * For other tests, this marks test loading as complete, but doesn't affect ongoing tests.     */    function done() {        if (tests.tests.length === 0) {            // `done` is invoked after handling uncaught exceptions, so if the            // harness status is already set, the corresponding message is more            // descriptive than the generic message defined here.            if (tests.status.status === null) {                tests.status.status = tests.status.ERROR;                tests.status.message = "done() was called without first defining any tests";            }            tests.complete();            return;        }        if (tests.file_is_test) {            // file is test files never have asynchronous cleanup logic,            // meaning the fully-synchronous `done` function can be used here.            tests.tests[0].done();        }        tests.end_wait();    }    /**     * @deprecated generate a list of tests from a function and list of arguments     *     * This is deprecated because it runs all the tests outside of the test functions     * and as a result any test throwing an exception will result in no tests being     * run. In almost all cases, you should simply call test within the loop you would     * use to generate the parameter list array.     *     * @param {Function} func - The function that will be called for each generated tests.     * @param {Any[][]} args - An array of arrays. Each nested array     * has the structure `[testName, ...testArgs]`. For each of these nested arrays     * array, a test is generated with name `testName` and test function equivalent to     * `func(..testArgs)`.     */    function generate_tests(func, args, properties) {        forEach(args, function(x, i)                {                    var name = x[0];                    test(function()                         {                             func.apply(this, x.slice(1));                         },                         name,                         Array.isArray(properties) ? properties[i] : properties);                });    }    /**     * @deprecated     *     * Register a function as a DOM event listener to the     * given object for the event bubbling phase.     *     * @param {EventTarget} object - Event target     * @param {string} event - Event name     * @param {Function} callback - Event handler.     */    function on_event(object, event, callback)    {        object.addEventListener(event, callback, false);    }    /**     * Global version of :js:func:`Test.step_timeout` for use in single page tests.     *     * @param {Function} func - Function to run after the timeout     * @param {number} timeout - Time in ms to wait before running the     * test step. The actual wait time is ``timeout`` x     * ``timeout_multiplier``.     */    function step_timeout(func, timeout) {        var outer_this = this;        var args = Array.prototype.slice.call(arguments, 2);        return setTimeout(function() {            func.apply(outer_this, args);        }, timeout * tests.timeout_multiplier);    }    expose(test, 'test');    expose(async_test, 'async_test');    expose(promise_test, 'promise_test');    expose(promise_rejects_js, 'promise_rejects_js');    expose(promise_rejects_dom, 'promise_rejects_dom');    expose(promise_rejects_exactly, 'promise_rejects_exactly');    expose(generate_tests, 'generate_tests');    expose(setup, 'setup');    expose(promise_setup, 'promise_setup');    expose(done, 'done');    expose(on_event, 'on_event');    expose(step_timeout, 'step_timeout');    /*     * Return a string truncated to the given length, with ... added at the end     * if it was longer.     */    function truncate(s, len)    {        if (s.length > len) {            return s.substring(0, len - 3) + "...";        }        return s;    }    /*     * Return true if object is probably a Node object.     */    function is_node(object)    {        // I use duck-typing instead of instanceof, because        // instanceof doesn't work if the node is from another window (like an        // iframe's contentWindow):        // http://www.w3.org/Bugs/Public/show_bug.cgi?id=12295        try {            var has_node_properties = ("nodeType" in object &&                                       "nodeName" in object &&                                       "nodeValue" in object &&                                       "childNodes" in object);        } catch (e) {            // We're probably cross-origin, which means we aren't a node            return false;        }        if (has_node_properties) {            try {                object.nodeType;            } catch (e) {                // The object is probably Node.prototype or another prototype                // object that inherits from it, and not a Node instance.                return false;            }            return true;        }        return false;    }    var replacements = {        "0": "0",        "1": "x01",        "2": "x02",        "3": "x03",        "4": "x04",        "5": "x05",        "6": "x06",        "7": "x07",        "8": "b",        "9": "t",        "10": "n",        "11": "v",        "12": "f",        "13": "r",        "14": "x0e",        "15": "x0f",        "16": "x10",        "17": "x11",        "18": "x12",        "19": "x13",        "20": "x14",        "21": "x15",        "22": "x16",        "23": "x17",        "24": "x18",        "25": "x19",        "26": "x1a",        "27": "x1b",        "28": "x1c",        "29": "x1d",        "30": "x1e",        "31": "x1f",        "0xfffd": "ufffd",        "0xfffe": "ufffe",        "0xffff": "uffff",    };    /**     * Convert a value to a nice, human-readable string     *     * When many JavaScript Object values are coerced to a String, the     * resulting value will be ``"[object Object]"``. This obscures     * helpful information, making the coerced value unsuitable for     * use in assertion messages, test names, and debugging     * statements. `format_value` produces more distinctive string     * representations of many kinds of objects, including arrays and     * the more important DOM Node types. It also translates String     * values containing control characters to include human-readable     * representations.     *     * @example     * // "Document node with 2 children"     * format_value(document);     * @example     * // "\"foo\\uffffbar\""     * format_value("foo\uffffbar");     * @example     * // "[-0, Infinity]"     * format_value([-0, Infinity]);     * @param {Any} val - The value to convert to a string.     * @returns {string} - A string representation of ``val``, optimised for human readability.     */    function format_value(val, seen)    {        if (!seen) {            seen = [];        }        if (typeof val === "object" && val !== null) {            if (seen.indexOf(val) >= 0) {                return "[...]";            }            seen.push(val);        }        if (Array.isArray(val)) {            let output = "[";            if (val.beginEllipsis !== undefined) {                output += "…, ";            }            output += val.map(function(x) {return format_value(x, seen);}).join(", ");            if (val.endEllipsis !== undefined) {                output += ", …";            }            return output + "]";        }        switch (typeof val) {        case "string":            val = val.replace(/\\/g, "\\\\");            for (var p in replacements) {                var replace = "\\" + replacements[p];                val = val.replace(RegExp(String.fromCharCode(p), "g"), replace);            }            return '"' + val.replace(/"/g, '\\"') + '"';        case "boolean":        case "undefined":            return String(val);        case "number":            // In JavaScript, -0 === 0 and String(-0) == "0", so we have to            // special-case.            if (val === -0 && 1/val === -Infinity) {                return "-0";            }            return String(val);        case "object":            if (val === null) {                return "null";            }            // Special-case Node objects, since those come up a lot in my tests.  I            // ignore namespaces.            if (is_node(val)) {                switch (val.nodeType) {                case Node.ELEMENT_NODE:                    var ret = "<" + val.localName;                    for (var i = 0; i < val.attributes.length; i++) {                        ret += " " + val.attributes[i].name + '="' + val.attributes[i].value + '"';                    }                    ret += ">" + val.innerHTML + "</" + val.localName + ">";                    return "Element node " + truncate(ret, 60);                case Node.TEXT_NODE:                    return 'Text node "' + truncate(val.data, 60) + '"';                case Node.PROCESSING_INSTRUCTION_NODE:                    return "ProcessingInstruction node with target " + format_value(truncate(val.target, 60)) + " and data " + format_value(truncate(val.data, 60));                case Node.COMMENT_NODE:                    return "Comment node <!--" + truncate(val.data, 60) + "-->";                case Node.DOCUMENT_NODE:                    return "Document node with " + val.childNodes.length + (val.childNodes.length == 1 ? " child" : " children");                case Node.DOCUMENT_TYPE_NODE:                    return "DocumentType node";                case Node.DOCUMENT_FRAGMENT_NODE:                    return "DocumentFragment node with " + val.childNodes.length + (val.childNodes.length == 1 ? " child" : " children");                default:                    return "Node object of unknown type";                }            }        /* falls through */        default:            try {                return typeof val + ' "' + truncate(String(val), 1000) + '"';            } catch(e) {                return ("[stringifying object threw " + String(e) +                        " with type " + String(typeof e) + "]");            }        }    }    expose(format_value, "format_value");    /*     * Assertions     */    function expose_assert(f, name) {        function assert_wrapper(...args) {            let status = Test.statuses.TIMEOUT;            let stack = null;            try {                if (settings.debug) {                    console.debug("ASSERT", name, tests.current_test && tests.current_test.name, args);                }                if (tests.output) {                    tests.set_assert(name, args);                }                const rv = f.apply(undefined, args);                status = Test.statuses.PASS;                return rv;            } catch(e) {                status = Test.statuses.FAIL;                stack = e.stack ? e.stack : null;                throw e;            } finally {                if (tests.output && !stack) {                    stack = get_stack();                }                if (tests.output) {                    tests.set_assert_status(status, stack);                }            }        }        expose(assert_wrapper, name);    }    /**     * Assert that ``actual`` is strictly true     *     * @param {Any} actual - Value that is asserted to be true     * @param {string} [description] - Description of the condition being tested     */    function assert_true(actual, description)    {        assert(actual === true, "assert_true", description,                                "expected true got ${actual}", {actual:actual});    }    expose_assert(assert_true, "assert_true");    /**     * Assert that ``actual`` is strictly false     *     * @param {Any} actual - Value that is asserted to be false     * @param {string} [description] - Description of the condition being tested     */    function assert_false(actual, description)    {        assert(actual === false, "assert_false", description,                                 "expected false got ${actual}", {actual:actual});    }    expose_assert(assert_false, "assert_false");    function same_value(x, y) {        if (y !== y) {            //NaN case            return x !== x;        }        if (x === 0 && y === 0) {            //Distinguish +0 and -0            return 1/x === 1/y;        }        return x === y;    }    /**     * Assert that ``actual`` is the same value as ``expected``.     *     * For objects this compares by cobject identity; for primitives     * this distinguishes between 0 and -0, and has correct handling     * of NaN.     *     * @param {Any} actual - Test value.     * @param {Any} expected - Expected value.     * @param {string} [description] - Description of the condition being tested.     */    function assert_equals(actual, expected, description)    {         /*          * Test if two primitives are equal or two objects          * are the same object          */        if (typeof actual != typeof expected) {            assert(false, "assert_equals", description,                          "expected (" + typeof expected + ") ${expected} but got (" + typeof actual + ") ${actual}",                          {expected:expected, actual:actual});            return;        }        assert(same_value(actual, expected), "assert_equals", description,                                             "expected ${expected} but got ${actual}",                                             {expected:expected, actual:actual});    }    expose_assert(assert_equals, "assert_equals");    /**     * Assert that ``actual`` is not the same value as ``expected``.     *     * Comparison is as for :js:func:`assert_equals`.     *     * @param {Any} actual - Test value.     * @param {Any} expected - The value ``actual`` is expected to be different to.     * @param {string} [description] - Description of the condition being tested.     */    function assert_not_equals(actual, expected, description)    {        assert(!same_value(actual, expected), "assert_not_equals", description,                                              "got disallowed value ${actual}",                                              {actual:actual});    }    expose_assert(assert_not_equals, "assert_not_equals");    /**     * Assert that ``expected`` is an array and ``actual`` is one of the members.     * This is implemented using ``indexOf``, so doesn't handle NaN or ±0 correctly.     *     * @param {Any} actual - Test value.     * @param {Array} expected - An array that ``actual`` is expected to     * be a member of.     * @param {string} [description] - Description of the condition being tested.     */    function assert_in_array(actual, expected, description)    {        assert(expected.indexOf(actual) != -1, "assert_in_array", description,                                               "value ${actual} not in array ${expected}",                                               {actual:actual, expected:expected});    }    expose_assert(assert_in_array, "assert_in_array");    // This function was deprecated in July of 2015.    // See https://github.com/web-platform-tests/wpt/issues/2033    /**     * @deprecated     * Recursively compare two objects for equality.     *     * See `Issue 2033     * <https://github.com/web-platform-tests/wpt/issues/2033>`_ for     * more information.     *     * @param {Object} actual - Test value.     * @param {Object} expected - Expected value.     * @param {string} [description] - Description of the condition being tested.     */    function assert_object_equals(actual, expected, description)    {         assert(typeof actual === "object" && actual !== null, "assert_object_equals", description,                                                               "value is ${actual}, expected object",                                                               {actual: actual});         //This needs to be improved a great deal         function check_equal(actual, expected, stack)         {             stack.push(actual);             var p;             for (p in actual) {                 assert(expected.hasOwnProperty(p), "assert_object_equals", description,                                                    "unexpected property ${p}", {p:p});                 if (typeof actual[p] === "object" && actual[p] !== null) {                     if (stack.indexOf(actual[p]) === -1) {                         check_equal(actual[p], expected[p], stack);                     }                 } else {                     assert(same_value(actual[p], expected[p]), "assert_object_equals", description,                                                       "property ${p} expected ${expected} got ${actual}",                                                       {p:p, expected:expected[p], actual:actual[p]});                 }             }             for (p in expected) {                 assert(actual.hasOwnProperty(p),                        "assert_object_equals", description,                        "expected property ${p} missing", {p:p});             }             stack.pop();         }         check_equal(actual, expected, []);    }    expose_assert(assert_object_equals, "assert_object_equals");    /**     * Assert that ``actual`` and ``expected`` are both arrays, and that the array properties of     * ``actual`` and ``expected`` are all the same value (as for :js:func:`assert_equals`).     *     * @param {Array} actual - Test array.     * @param {Array} expected - Array that is expected to contain the same values as ``actual``.     * @param {string} [description] - Description of the condition being tested.     */    function assert_array_equals(actual, expected, description)    {        const max_array_length = 20;        function shorten_array(arr, offset = 0) {            // Make ", …" only show up when it would likely reduce the length, not accounting for            // fonts.            if (arr.length < max_array_length + 2) {                return arr;            }            // By default we want half the elements after the offset and half before            // But if that takes us past the end of the array, we have more before, and            // if it takes us before the start we have more after.            const length_after_offset = Math.floor(max_array_length / 2);            let upper_bound = Math.min(length_after_offset + offset, arr.length);            const lower_bound = Math.max(upper_bound - max_array_length, 0);            if (lower_bound === 0) {                upper_bound = max_array_length;            }            const output = arr.slice(lower_bound, upper_bound);            if (lower_bound > 0) {                output.beginEllipsis = true;            }            if (upper_bound < arr.length) {                output.endEllipsis = true;            }            return output;        }        assert(typeof actual === "object" && actual !== null && "length" in actual,               "assert_array_equals", description,               "value is ${actual}, expected array",               {actual:actual});        assert(actual.length === expected.length,               "assert_array_equals", description,               "lengths differ, expected array ${expected} length ${expectedLength}, got ${actual} length ${actualLength}",               {expected:shorten_array(expected, expected.length - 1), expectedLength:expected.length,                actual:shorten_array(actual, actual.length - 1), actualLength:actual.length               });        for (var i = 0; i < actual.length; i++) {            assert(actual.hasOwnProperty(i) === expected.hasOwnProperty(i),                   "assert_array_equals", description,                   "expected property ${i} to be ${expected} but was ${actual} (expected array ${arrayExpected} got ${arrayActual})",                   {i:i, expected:expected.hasOwnProperty(i) ? "present" : "missing",                    actual:actual.hasOwnProperty(i) ? "present" : "missing",                    arrayExpected:shorten_array(expected, i), arrayActual:shorten_array(actual, i)});            assert(same_value(expected[i], actual[i]),                   "assert_array_equals", description,                   "expected property ${i} to be ${expected} but got ${actual} (expected array ${arrayExpected} got ${arrayActual})",                   {i:i, expected:expected[i], actual:actual[i],                    arrayExpected:shorten_array(expected, i), arrayActual:shorten_array(actual, i)});        }    }    expose_assert(assert_array_equals, "assert_array_equals");    /**     * Assert that each array property in ``actual`` is a number within     * ± `epsilon` of the corresponding property in `expected`.     *     * @param {Array} actual - Array of test values.     * @param {Array} expected - Array of values expected to be close to the values in ``actual``.     * @param {number} epsilon - Magnitude of allowed difference     * between each value in ``actual`` and ``expected``.     * @param {string} [description] - Description of the condition being tested.     */    function assert_array_approx_equals(actual, expected, epsilon, description)    {        /*         * Test if two primitive arrays are equal within +/- epsilon         */        assert(actual.length === expected.length,               "assert_array_approx_equals", description,               "lengths differ, expected ${expected} got ${actual}",               {expected:expected.length, actual:actual.length});        for (var i = 0; i < actual.length; i++) {            assert(actual.hasOwnProperty(i) === expected.hasOwnProperty(i),                   "assert_array_approx_equals", description,                   "property ${i}, property expected to be ${expected} but was ${actual}",                   {i:i, expected:expected.hasOwnProperty(i) ? "present" : "missing",                    actual:actual.hasOwnProperty(i) ? "present" : "missing"});            assert(typeof actual[i] === "number",                   "assert_array_approx_equals", description,                   "property ${i}, expected a number but got a ${type_actual}",                   {i:i, type_actual:typeof actual[i]});            assert(Math.abs(actual[i] - expected[i]) <= epsilon,                   "assert_array_approx_equals", description,                   "property ${i}, expected ${expected} +/- ${epsilon}, expected ${expected} but got ${actual}",                   {i:i, expected:expected[i], actual:actual[i], epsilon:epsilon});        }    }    expose_assert(assert_array_approx_equals, "assert_array_approx_equals");    /**     * Assert that ``actual`` is within ± ``epsilon`` of ``expected``.     *     * @param {number} actual - Test value.     * @param {number} expected - Value number is expected to be close to.     * @param {number} epsilon - Magnitude of allowed difference between ``actual`` and ``expected``.     * @param {string} [description] - Description of the condition being tested.     */    function assert_approx_equals(actual, expected, epsilon, description)    {        /*         * Test if two primitive numbers are equal within +/- epsilon         */        assert(typeof actual === "number",               "assert_approx_equals", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        // The epsilon math below does not place nice with NaN and Infinity        // But in this case Infinity = Infinity and NaN = NaN        if (isFinite(actual) || isFinite(expected)) {            assert(Math.abs(actual - expected) <= epsilon,                   "assert_approx_equals", description,                   "expected ${expected} +/- ${epsilon} but got ${actual}",                   {expected:expected, actual:actual, epsilon:epsilon});        } else {            assert_equals(actual, expected);        }    }    expose_assert(assert_approx_equals, "assert_approx_equals");    /**     * Assert that ``actual`` is a number less than ``expected``.     *     * @param {number} actual - Test value.     * @param {number} expected - Number that ``actual`` must be less than.     * @param {string} [description] - Description of the condition being tested.     */    function assert_less_than(actual, expected, description)    {        /*         * Test if a primitive number is less than another         */        assert(typeof actual === "number",               "assert_less_than", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual < expected,               "assert_less_than", description,               "expected a number less than ${expected} but got ${actual}",               {expected:expected, actual:actual});    }    expose_assert(assert_less_than, "assert_less_than");    /**     * Assert that ``actual`` is a number greater than ``expected``.     *     * @param {number} actual - Test value.     * @param {number} expected - Number that ``actual`` must be greater than.     * @param {string} [description] - Description of the condition being tested.     */    function assert_greater_than(actual, expected, description)    {        /*         * Test if a primitive number is greater than another         */        assert(typeof actual === "number",               "assert_greater_than", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual > expected,               "assert_greater_than", description,               "expected a number greater than ${expected} but got ${actual}",               {expected:expected, actual:actual});    }    expose_assert(assert_greater_than, "assert_greater_than");    /**     * Assert that ``actual`` is a number greater than ``lower`` and less     * than ``upper`` but not equal to either.     *     * @param {number} actual - Test value.     * @param {number} lower - Number that ``actual`` must be greater than.     * @param {number} upper - Number that ``actual`` must be less than.     * @param {string} [description] - Description of the condition being tested.     */    function assert_between_exclusive(actual, lower, upper, description)    {        /*         * Test if a primitive number is between two others         */        assert(typeof actual === "number",               "assert_between_exclusive", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual > lower && actual < upper,               "assert_between_exclusive", description,               "expected a number greater than ${lower} " +               "and less than ${upper} but got ${actual}",               {lower:lower, upper:upper, actual:actual});    }    expose_assert(assert_between_exclusive, "assert_between_exclusive");    /**     * Assert that ``actual`` is a number less than or equal to ``expected``.     *     * @param {number} actual - Test value.     * @param {number} expected - Number that ``actual`` must be less     * than or equal to.     * @param {string} [description] - Description of the condition being tested.     */    function assert_less_than_equal(actual, expected, description)    {        /*         * Test if a primitive number is less than or equal to another         */        assert(typeof actual === "number",               "assert_less_than_equal", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual <= expected,               "assert_less_than_equal", description,               "expected a number less than or equal to ${expected} but got ${actual}",               {expected:expected, actual:actual});    }    expose_assert(assert_less_than_equal, "assert_less_than_equal");    /**     * Assert that ``actual`` is a number greater than or equal to ``expected``.     *     * @param {number} actual - Test value.     * @param {number} expected - Number that ``actual`` must be greater     * than or equal to.     * @param {string} [description] - Description of the condition being tested.     */    function assert_greater_than_equal(actual, expected, description)    {        /*         * Test if a primitive number is greater than or equal to another         */        assert(typeof actual === "number",               "assert_greater_than_equal", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual >= expected,               "assert_greater_than_equal", description,               "expected a number greater than or equal to ${expected} but got ${actual}",               {expected:expected, actual:actual});    }    expose_assert(assert_greater_than_equal, "assert_greater_than_equal");    /**     * Assert that ``actual`` is a number greater than or equal to ``lower`` and less     * than or equal to ``upper``.     *     * @param {number} actual - Test value.     * @param {number} lower - Number that ``actual`` must be greater than or equal to.     * @param {number} upper - Number that ``actual`` must be less than or equal to.     * @param {string} [description] - Description of the condition being tested.     */    function assert_between_inclusive(actual, lower, upper, description)    {        /*         * Test if a primitive number is between to two others or equal to either of them         */        assert(typeof actual === "number",               "assert_between_inclusive", description,               "expected a number but got a ${type_actual}",               {type_actual:typeof actual});        assert(actual >= lower && actual <= upper,               "assert_between_inclusive", description,               "expected a number greater than or equal to ${lower} " +               "and less than or equal to ${upper} but got ${actual}",               {lower:lower, upper:upper, actual:actual});    }    expose_assert(assert_between_inclusive, "assert_between_inclusive");    /**     * Assert that ``actual`` matches the RegExp ``expected``.     *     * @param {String} actual - Test string.     * @param {RegExp} expected - RegExp ``actual`` must match.     * @param {string} [description] - Description of the condition being tested.     */    function assert_regexp_match(actual, expected, description) {        /*         * Test if a string (actual) matches a regexp (expected)         */        assert(expected.test(actual),               "assert_regexp_match", description,               "expected ${expected} but got ${actual}",               {expected:expected, actual:actual});    }    expose_assert(assert_regexp_match, "assert_regexp_match");    /**     * Assert that the class string of ``object`` as returned in     * ``Object.prototype.toString`` is equal to ``class_name``.     *     * @param {Object} object - Object to stringify.     * @param {string} class_string - Expected class string for ``object``.     * @param {string} [description] - Description of the condition being tested.     */    function assert_class_string(object, class_string, description) {        var actual = {}.toString.call(object);        var expected = "[object " + class_string + "]";        assert(same_value(actual, expected), "assert_class_string", description,                                             "expected ${expected} but got ${actual}",                                             {expected:expected, actual:actual});    }    expose_assert(assert_class_string, "assert_class_string");    /**     * Assert that ``object`` has an own property with name ``property_name``.     *     * @param {Object} object - Object that should have the given property.     * @param {string} property_name - Expected property name.     * @param {string} [description] - Description of the condition being tested.     */    function assert_own_property(object, property_name, description) {        assert(object.hasOwnProperty(property_name),               "assert_own_property", description,               "expected property ${p} missing", {p:property_name});    }    expose_assert(assert_own_property, "assert_own_property");    /**     * Assert that ``object`` does not have an own property with name ``property_name``.     *     * @param {Object} object - Object that should not have the given property.     * @param {string} property_name - Property name to test.     * @param {string} [description] - Description of the condition being tested.     */    function assert_not_own_property(object, property_name, description) {        assert(!object.hasOwnProperty(property_name),               "assert_not_own_property", description,               "unexpected property ${p} is found on object", {p:property_name});    }    expose_assert(assert_not_own_property, "assert_not_own_property");    function _assert_inherits(name) {        return function (object, property_name, description)        {            assert((typeof object === "object" && object !== null) ||                   typeof object === "function" ||                   // Or has [[IsHTMLDDA]] slot                   String(object) === "[object HTMLAllCollection]",                   name, description,                   "provided value is not an object");            assert("hasOwnProperty" in object,                   name, description,                   "provided value is an object but has no hasOwnProperty method");            assert(!object.hasOwnProperty(property_name),                   name, description,                   "property ${p} found on object expected in prototype chain",                   {p:property_name});            assert(property_name in object,                   name, description,                   "property ${p} not found in prototype chain",                   {p:property_name});        };    }    /**     * Assert that ``object`` does not have an own property with name     * ``property_name``, but inherits one through the prototype chain.     *     * @param {Object} object - Object that should have the given property in its prototype chain.     * @param {string} property_name - Expected property name.     * @param {string} [description] - Description of the condition being tested.     */    function assert_inherits(object, property_name, description) {        return _assert_inherits("assert_inherits")(object, property_name, description);    }    expose_assert(assert_inherits, "assert_inherits");    /**     * Alias for :js:func:`insert_inherits`.     *     * @param {Object} object - Object that should have the given property in its prototype chain.     * @param {string} property_name - Expected property name.     * @param {string} [description] - Description of the condition being tested.     */    function assert_idl_attribute(object, property_name, description) {        return _assert_inherits("assert_idl_attribute")(object, property_name, description);    }    expose_assert(assert_idl_attribute, "assert_idl_attribute");    /**     * Assert that ``object`` has a property named ``property_name`` and that the property is readonly.     *     * Note: The implementation tries to update the named property, so     * any side effects of updating will be triggered. Users are     * encouraged to instead inspect the property descriptor of ``property_name`` on ``object``.     *     * @param {Object} object - Object that should have the given property in its prototype chain.     * @param {string} property_name - Expected property name.     * @param {string} [description] - Description of the condition being tested.     */    function assert_readonly(object, property_name, description)    {         var initial_value = object[property_name];         try {             //Note that this can have side effects in the case where             //the property has PutForwards             object[property_name] = initial_value + "a"; //XXX use some other value here?             assert(same_value(object[property_name], initial_value),                    "assert_readonly", description,                    "changing property ${p} succeeded",                    {p:property_name});         } finally {             object[property_name] = initial_value;         }    }    expose_assert(assert_readonly, "assert_readonly");    /**     * Assert a JS Error with the expected constructor is thrown.     *     * @param {object} constructor The expected exception constructor.     * @param {Function} func Function which should throw.     * @param {string} [description] Error description for the case that the error is not thrown.     */    function assert_throws_js(constructor, func, description)    {        assert_throws_js_impl(constructor, func, description,                              "assert_throws_js");    }    expose_assert(assert_throws_js, "assert_throws_js");    /**     * Like assert_throws_js but allows specifying the assertion type     * (assert_throws_js or promise_rejects_js, in practice).     */    function assert_throws_js_impl(constructor, func, description,                                   assertion_type)    {        try {            func.call(this);            assert(false, assertion_type, description,                   "${func} did not throw", {func:func});        } catch (e) {            if (e instanceof AssertionError) {                throw e;            }            // Basic sanity-checks on the thrown exception.            assert(typeof e === "object",                   assertion_type, description,                   "${func} threw ${e} with type ${type}, not an object",                   {func:func, e:e, type:typeof e});            assert(e !== null,                   assertion_type, description,                   "${func} threw null, not an object",                   {func:func});            // Basic sanity-check on the passed-in constructor            assert(typeof constructor == "function",                   assertion_type, description,                   "${constructor} is not a constructor",                   {constructor:constructor});            var obj = constructor;            while (obj) {                if (typeof obj === "function" &&                    obj.name === "Error") {                    break;                }                obj = Object.getPrototypeOf(obj);            }            assert(obj != null,                   assertion_type, description,                   "${constructor} is not an Error subtype",                   {constructor:constructor});            // And checking that our exception is reasonable            assert(e.constructor === constructor &&                   e.name === constructor.name,                   assertion_type, description,                   "${func} threw ${actual} (${actual_name}) expected instance of ${expected} (${expected_name})",                   {func:func, actual:e, actual_name:e.name,                    expected:constructor,                    expected_name:constructor.name});        }    }    // TODO: Figure out how to document the overloads better.    // sphinx-js doesn't seem to handle @variation correctly,    // and only expects a single JSDoc entry per function.    /**     * Assert a DOMException with the expected type is thrown.     *     * There are two ways of calling assert_throws_dom:     *     * 1) If the DOMException is expected to come from the current global, the     * second argument should be the function expected to throw and a third,     * optional, argument is the assertion description.     *     * 2) If the DOMException is expected to come from some other global, the     * second argument should be the DOMException constructor from that global,     * the third argument the function expected to throw, and the fourth, optional,     * argument the assertion description.     *     * @param {number|string} type - The expected exception name or     * code.  See the `table of names and codes     * <https://webidl.spec.whatwg.org/#dfn-error-names-table>`_. If a     * number is passed it should be one of the numeric code values in     * that table (e.g. 3, 4, etc).  If a string is passed it can     * either be an exception name (e.g. "HierarchyRequestError",     * "WrongDocumentError") or the name of the corresponding error     * code (e.g. "``HIERARCHY_REQUEST_ERR``", "``WRONG_DOCUMENT_ERR``").     * @param {Function} descriptionOrFunc - The function expected to     * throw (if the exception comes from another global), or the     * optional description of the condition being tested (if the     * exception comes from the current global).     * @param {string} [description] - Description of the condition     * being tested (if the exception comes from another global).     *     */    function assert_throws_dom(type, funcOrConstructor, descriptionOrFunc, maybeDescription)    {        let constructor, func, description;        if (funcOrConstructor.name === "DOMException") {            constructor = funcOrConstructor;            func = descriptionOrFunc;            description = maybeDescription;        } else {            constructor = self.DOMException;            func = funcOrConstructor;            description = descriptionOrFunc;            assert(maybeDescription === undefined,                   "Too many args pased to no-constructor version of assert_throws_dom");        }        assert_throws_dom_impl(type, func, description, "assert_throws_dom", constructor)    }    expose_assert(assert_throws_dom, "assert_throws_dom");    /**     * Similar to assert_throws_dom but allows specifying the assertion type     * (assert_throws_dom or promise_rejects_dom, in practice).  The     * "constructor" argument must be the DOMException constructor from the     * global we expect the exception to come from.     */    function assert_throws_dom_impl(type, func, description, assertion_type, constructor)    {        try {            func.call(this);            assert(false, assertion_type, description,                   "${func} did not throw", {func:func});        } catch (e) {            if (e instanceof AssertionError) {                throw e;            }            // Basic sanity-checks on the thrown exception.            assert(typeof e === "object",                   assertion_type, description,                   "${func} threw ${e} with type ${type}, not an object",                   {func:func, e:e, type:typeof e});            assert(e !== null,                   assertion_type, description,                   "${func} threw null, not an object",                   {func:func});            // Sanity-check our type            assert(typeof type == "number" ||                   typeof type == "string",                   assertion_type, description,                   "${type} is not a number or string",                   {type:type});            var codename_name_map = {                INDEX_SIZE_ERR: 'IndexSizeError',                HIERARCHY_REQUEST_ERR: 'HierarchyRequestError',                WRONG_DOCUMENT_ERR: 'WrongDocumentError',                INVALID_CHARACTER_ERR: 'InvalidCharacterError',                NO_MODIFICATION_ALLOWED_ERR: 'NoModificationAllowedError',                NOT_FOUND_ERR: 'NotFoundError',                NOT_SUPPORTED_ERR: 'NotSupportedError',                INUSE_ATTRIBUTE_ERR: 'InUseAttributeError',                INVALID_STATE_ERR: 'InvalidStateError',                SYNTAX_ERR: 'SyntaxError',                INVALID_MODIFICATION_ERR: 'InvalidModificationError',                NAMESPACE_ERR: 'NamespaceError',                INVALID_ACCESS_ERR: 'InvalidAccessError',                TYPE_MISMATCH_ERR: 'TypeMismatchError',                SECURITY_ERR: 'SecurityError',                NETWORK_ERR: 'NetworkError',                ABORT_ERR: 'AbortError',                URL_MISMATCH_ERR: 'URLMismatchError',                QUOTA_EXCEEDED_ERR: 'QuotaExceededError',                TIMEOUT_ERR: 'TimeoutError',                INVALID_NODE_TYPE_ERR: 'InvalidNodeTypeError',                DATA_CLONE_ERR: 'DataCloneError'            };            var name_code_map = {                IndexSizeError: 1,                HierarchyRequestError: 3,                WrongDocumentError: 4,                InvalidCharacterError: 5,                NoModificationAllowedError: 7,                NotFoundError: 8,                NotSupportedError: 9,                InUseAttributeError: 10,                InvalidStateError: 11,                SyntaxError: 12,                InvalidModificationError: 13,                NamespaceError: 14,                InvalidAccessError: 15,                TypeMismatchError: 17,                SecurityError: 18,                NetworkError: 19,                AbortError: 20,                URLMismatchError: 21,                QuotaExceededError: 22,                TimeoutError: 23,                InvalidNodeTypeError: 24,                DataCloneError: 25,                EncodingError: 0,                NotReadableError: 0,                UnknownError: 0,                ConstraintError: 0,                DataError: 0,                TransactionInactiveError: 0,                ReadOnlyError: 0,                VersionError: 0,                OperationError: 0,                NotAllowedError: 0            };            var code_name_map = {};            for (var key in name_code_map) {                if (name_code_map[key] > 0) {                    code_name_map[name_code_map[key]] = key;                }            }            var required_props = {};            var name;            if (typeof type === "number") {                if (type === 0) {                    throw new AssertionError('Test bug: ambiguous DOMException code 0 passed to assert_throws_dom()');                } else if (!(type in code_name_map)) {                    throw new AssertionError('Test bug: unrecognized DOMException code "' + type + '" passed to assert_throws_dom()');                }                name = code_name_map[type];                required_props.code = type;            } else if (typeof type === "string") {                name = type in codename_name_map ? codename_name_map[type] : type;                if (!(name in name_code_map)) {                    throw new AssertionError('Test bug: unrecognized DOMException code name or name "' + type + '" passed to assert_throws_dom()');                }                required_props.code = name_code_map[name];            }            if (required_props.code === 0 ||               ("name" in e &&                e.name !== e.name.toUpperCase() &&                e.name !== "DOMException")) {                // New style exception: also test the name property.                required_props.name = name;            }            for (var prop in required_props) {                assert(prop in e && e[prop] == required_props[prop],                       assertion_type, description,                       "${func} threw ${e} that is not a DOMException " + type + ": property ${prop} is equal to ${actual}, expected ${expected}",                       {func:func, e:e, prop:prop, actual:e[prop], expected:required_props[prop]});            }            // Check that the exception is from the right global.  This check is last            // so more specific, and more informative, checks on the properties can            // happen in case a totally incorrect exception is thrown.            assert(e.constructor === constructor,                   assertion_type, description,                   "${func} threw an exception from the wrong global",                   {func});        }    }    /**     * Assert the provided value is thrown.     *     * @param {value} exception The expected exception.     * @param {Function} func Function which should throw.     * @param {string} [description] Error description for the case that the error is not thrown.     */    function assert_throws_exactly(exception, func, description)    {        assert_throws_exactly_impl(exception, func, description,                                   "assert_throws_exactly");    }    expose_assert(assert_throws_exactly, "assert_throws_exactly");    /**     * Like assert_throws_exactly but allows specifying the assertion type     * (assert_throws_exactly or promise_rejects_exactly, in practice).     */    function assert_throws_exactly_impl(exception, func, description,                                        assertion_type)    {        try {            func.call(this);            assert(false, assertion_type, description,                   "${func} did not throw", {func:func});        } catch (e) {            if (e instanceof AssertionError) {                throw e;            }            assert(same_value(e, exception), assertion_type, description,                   "${func} threw ${e} but we expected it to throw ${exception}",                   {func:func, e:e, exception:exception});        }    }    /**     * Asserts if called. Used to ensure that a specific codepath is     * not taken e.g. that an error event isn't fired.     *     * @param {string} [description] - Description of the condition being tested.     */    function assert_unreached(description) {         assert(false, "assert_unreached", description,                "Reached unreachable code");    }    expose_assert(assert_unreached, "assert_unreached");    /**     * @callback AssertFunc     * @param {Any} actual     * @param {Any} expected     * @param {Any[]} args     */    /**     * Asserts that ``actual`` matches at least one value of ``expected``     * according to a comparison defined by ``assert_func``.     *     * Note that tests with multiple allowed pass conditions are bad     * practice unless the spec specifically allows multiple     * behaviours. Test authors should not use this method simply to     * hide UA bugs.     *     * @param {AssertFunc} assert_func - Function to compare actual     * and expected. It must throw when the comparison fails and     * return when the comparison passes.     * @param {Any} actual - Test value.     * @param {Array} expected_array - Array of possible expected values.     * @param {Any[]} args - Additional arguments to pass to ``assert_func``.     */    function assert_any(assert_func, actual, expected_array, ...args)    {        var errors = [];        var passed = false;        forEach(expected_array,                function(expected)                {                    try {                        assert_func.apply(this, [actual, expected].concat(args));                        passed = true;                    } catch (e) {                        errors.push(e.message);                    }                });        if (!passed) {            throw new AssertionError(errors.join("\n\n"));        }    }    // FIXME: assert_any cannot use expose_assert, because assert_wrapper does    // not support nested assert calls (e.g. to assert_func). We need to    // support bypassing assert_wrapper for the inner asserts here.    expose(assert_any, "assert_any");    /**     * Assert that a feature is implemented, based on a 'truthy' condition.     *     * This function should be used to early-exit from tests in which there is     * no point continuing without support for a non-optional spec or spec     * feature. For example:     *     *     assert_implements(window.Foo, 'Foo is not supported');     *     * @param {object} condition The truthy value to test     * @param {string} [description] Error description for the case that the condition is not truthy.     */    function assert_implements(condition, description) {        assert(!!condition, "assert_implements", description);    }    expose_assert(assert_implements, "assert_implements")    /**     * Assert that an optional feature is implemented, based on a 'truthy' condition.     *     * This function should be used to early-exit from tests in which there is     * no point continuing without support for an explicitly optional spec or     * spec feature. For example:     *     *     assert_implements_optional(video.canPlayType("video/webm"),     *                                "webm video playback not supported");     *     * @param {object} condition The truthy value to test     * @param {string} [description] Error description for the case that the condition is not truthy.     */    function assert_implements_optional(condition, description) {        if (!condition) {            throw new OptionalFeatureUnsupportedError(description);        }    }    expose_assert(assert_implements_optional, "assert_implements_optional");    /**     * @class     *     * A single subtest. A Test is not constructed directly but via the     * :js:func:`test`, :js:func:`async_test` or :js:func:`promise_test` functions.     *     * @param {string} name - This must be unique in a given file and must be     * invariant between runs.     *     */    function Test(name, properties)    {        if (tests.file_is_test && tests.tests.length) {            throw new Error("Tried to create a test with file_is_test");        }        /** The test name. */        this.name = name;        this.phase = (tests.is_aborted || tests.phase === tests.phases.COMPLETE) ?            this.phases.COMPLETE : this.phases.INITIAL;        /** The test status code.*/        this.status = this.NOTRUN;        this.timeout_id = null;        this.index = null;        this.properties = properties || {};        this.timeout_length = settings.test_timeout;        if (this.timeout_length !== null) {            this.timeout_length *= tests.timeout_multiplier;        }        /** A message indicating the reason for test failure. */        this.message = null;        /** Stack trace in case of failure. */        this.stack = null;        this.steps = [];        this._is_promise_test = false;        this.cleanup_callbacks = [];        this._user_defined_cleanup_count = 0;        this._done_callbacks = [];        // Tests declared following harness completion are likely an indication        // of a programming error, but they cannot be reported        // deterministically.        if (tests.phase === tests.phases.COMPLETE) {            return;        }        tests.push(this);    }    /**     * Enum of possible test statuses.     *     * :values:     *   - ``PASS``     *   - ``FAIL``     *   - ``TIMEOUT``     *   - ``NOTRUN``     *   - ``PRECONDITION_FAILED``     */    Test.statuses = {        PASS:0,        FAIL:1,        TIMEOUT:2,        NOTRUN:3,        PRECONDITION_FAILED:4    };    Test.prototype = merge({}, Test.statuses);    Test.prototype.phases = {        INITIAL:0,        STARTED:1,        HAS_RESULT:2,        CLEANING:3,        COMPLETE:4    };    Test.prototype.status_formats = {        0: "Pass",        1: "Fail",        2: "Timeout",        3: "Not Run",        4: "Optional Feature Unsupported",    }    Test.prototype.format_status = function() {        return this.status_formats[this.status];    }    Test.prototype.structured_clone = function()    {        if (!this._structured_clone) {            var msg = this.message;            msg = msg ? String(msg) : msg;            this._structured_clone = merge({                name:String(this.name),                properties:merge({}, this.properties),                phases:merge({}, this.phases)            }, Test.statuses);        }        this._structured_clone.status = this.status;        this._structured_clone.message = this.message;        this._structured_clone.stack = this.stack;        this._structured_clone.index = this.index;        this._structured_clone.phase = this.phase;        return this._structured_clone;    };    /**     * Run a single step of an ongoing test.     *     * @param {string} func - Callback function to run as a step. If     * this throws an :js:func:`AssertionError`, or any other     * exception, the :js:class:`Test` status is set to ``FAIL``.     * @param {Object} [this_obj] - The object to use as the this     * value when calling ``func``. Defaults to the  :js:class:`Test` object.     */    Test.prototype.step = function(func, this_obj)    {        if (this.phase > this.phases.STARTED) {            return;        }        if (settings.debug && this.phase !== this.phases.STARTED) {            console.log("TEST START", this.name);        }        this.phase = this.phases.STARTED;        //If we don't get a result before the harness times out that will be a test timeout        this.set_status(this.TIMEOUT, "Test timed out");        tests.started = true;        tests.current_test = this;        tests.notify_test_state(this);        if (this.timeout_id === null) {            this.set_timeout();        }        this.steps.push(func);        if (arguments.length === 1) {            this_obj = this;        }        if (settings.debug) {            console.debug("TEST STEP", this.name);        }        try {            return func.apply(this_obj, Array.prototype.slice.call(arguments, 2));        } catch (e) {            if (this.phase >= this.phases.HAS_RESULT) {                return;            }            var status = e instanceof OptionalFeatureUnsupportedError ? this.PRECONDITION_FAILED : this.FAIL;            var message = String((typeof e === "object" && e !== null) ? e.message : e);            var stack = e.stack ? e.stack : null;            this.set_status(status, message, stack);            this.phase = this.phases.HAS_RESULT;            this.done();        } finally {            this.current_test = null;        }    };    /**     * Wrap a function so that it runs as a step of the current test.     *     * This allows creating a callback function that will run as a     * test step.     *     * @example     * let t = async_test("Example");     * onload = t.step_func(e => {     *   assert_equals(e.name, "load");     *   // Mark the test as complete.     *   t.done();     * })     *     * @param {string} func - Function to run as a step. If this     * throws an :js:func:`AssertionError`, or any other exception,     * the :js:class:`Test` status is set to ``FAIL``.     * @param {Object} [this_obj] - The object to use as the this     * value when calling ``func``. Defaults to the :js:class:`Test` object.     */    Test.prototype.step_func = function(func, this_obj)    {        var test_this = this;        if (arguments.length === 1) {            this_obj = test_this;        }        return function()        {            return test_this.step.apply(test_this, [func, this_obj].concat(                Array.prototype.slice.call(arguments)));        };    };    /**     * Wrap a function so that it runs as a step of the current test,     * and automatically marks the test as complete if the function     * returns without error.     *     * @param {string} func - Function to run as a step. If this     * throws an :js:func:`AssertionError`, or any other exception,     * the :js:class:`Test` status is set to ``FAIL``. If it returns     * without error the status is set to ``PASS``.     * @param {Object} [this_obj] - The object to use as the this     * value when calling `func`. Defaults to the :js:class:`Test` object.     */    Test.prototype.step_func_done = function(func, this_obj)    {        var test_this = this;        if (arguments.length === 1) {            this_obj = test_this;        }        return function()        {            if (func) {                test_this.step.apply(test_this, [func, this_obj].concat(                    Array.prototype.slice.call(arguments)));            }            test_this.done();        };    };    /**     * Return a function that automatically sets the current test to     * ``FAIL`` if it's called.     *     * @param {string} [description] - Error message to add to assert     * in case of failure.     *     */    Test.prototype.unreached_func = function(description)    {        return this.step_func(function() {            assert_unreached(description);        });    };    /**     * Run a function as a step of the test after a given timeout.     *     * This multiplies the timeout by the global timeout multiplier to     * account for the expected execution speed of the current test     * environment. For example ``test.step_timeout(f, 2000)`` with a     * timeout multiplier of 2 will wait for 4000ms before calling ``f``.     *     * In general it's encouraged to use :js:func:`Test.step_wait` or     * :js:func:`step_wait_func` in preference to this function where possible,     * as they provide better test performance.     *     * @param {Function} func - Function to run as a test     * step.     * @param {number} timeout - Time in ms to wait before running the     * test step. The actual wait time is ``timeout`` x     * ``timeout_multiplier``.     *     */    Test.prototype.step_timeout = function(func, timeout) {        var test_this = this;        var args = Array.prototype.slice.call(arguments, 2);        return setTimeout(this.step_func(function() {            return func.apply(test_this, args);        }), timeout * tests.timeout_multiplier);    };    /**     * Poll for a function to return true, and call a callback     * function once it does, or assert if a timeout is     * reached. This is preferred over a simple step_timeout     * whenever possible since it allows the timeout to be longer     * to reduce intermittents without compromising test execution     * speed when the condition is quickly met.     *     * @param {Function} cond A function taking no arguments and     *                        returning a boolean. The callback is called     *                        when this function returns true.     * @param {Function} func A function taking no arguments to call once     *                        the condition is met.     * @param {string} [description] Error message to add to assert in case of     *                               failure.     * @param {number} timeout Timeout in ms. This is multiplied by the global     *                         timeout_multiplier     * @param {number} interval Polling interval in ms     *     */    Test.prototype.step_wait_func = function(cond, func, description,                                             timeout=3000, interval=100) {        var timeout_full = timeout * tests.timeout_multiplier;        var remaining = Math.ceil(timeout_full / interval);        var test_this = this;        var wait_for_inner = test_this.step_func(() => {            if (cond()) {                func();            } else {                if(remaining === 0) {                    assert(false, "step_wait_func", description,                           "Timed out waiting on condition");                }                remaining--;                setTimeout(wait_for_inner, interval);            }        });        wait_for_inner();    };    /**     * Poll for a function to return true, and invoke a callback     * followed by this.done() once it does, or assert if a timeout     * is reached. This is preferred over a simple step_timeout     * whenever possible since it allows the timeout to be longer     * to reduce intermittents without compromising test execution speed     * when the condition is quickly met.     *     * @example     * async_test(t => {     *  const popup = window.open("resources/coop-coep.py?coop=same-origin&coep=&navigate=about:blank");     *  t.add_cleanup(() => popup.close());     *  assert_equals(window, popup.opener);     *     *  popup.onload = t.step_func(() => {     *    assert_true(popup.location.href.endsWith("&navigate=about:blank"));     *    // Use step_wait_func_done as about:blank cannot message back.     *    t.step_wait_func_done(() => popup.location.href === "about:blank");     *  });     * }, "Navigating a popup to about:blank");     *     * @param {Function} cond A function taking no arguments and     *                        returning a boolean. The callback is called     *                        when this function returns true.     * @param {Function} func A function taking no arguments to call once     *                        the condition is met.     * @param {string} [description] Error message to add to assert in case of     *                               failure.     * @param {number} timeout Timeout in ms. This is multiplied by the global     *                         timeout_multiplier     * @param {number} interval Polling interval in ms     *     */    Test.prototype.step_wait_func_done = function(cond, func, description,                                                  timeout=3000, interval=100) {         this.step_wait_func(cond, () => {            if (func) {                func();            }            this.done();         }, description, timeout, interval);    };    /**     * Poll for a function to return true, and resolve a promise     * once it does, or assert if a timeout is reached. This is     * preferred over a simple step_timeout whenever possible     * since it allows the timeout to be longer to reduce     * intermittents without compromising test execution speed     * when the condition is quickly met.     *     * @example     * promise_test(async t => {     *  // …     * await t.step_wait(() => frame.contentDocument === null, "Frame navigated to a cross-origin document");     * // …     * }, "");     *     * @param {Function} cond A function taking no arguments and     *                        returning a boolean.     * @param {string} [description] Error message to add to assert in case of     *                              failure.     * @param {number} timeout Timeout in ms. This is multiplied by the global     *                         timeout_multiplier     * @param {number} interval Polling interval in ms     * @returns {Promise} Promise resolved once cond is met.     *     */    Test.prototype.step_wait = function(cond, description, timeout=3000, interval=100) {        return new Promise(resolve => {            this.step_wait_func(cond, resolve, description, timeout, interval);        });    }    /*     * Private method for registering cleanup functions. `testharness.js`     * internals should use this method instead of the public `add_cleanup`     * method in order to hide implementation details from the harness status     * message in the case errors.     */    Test.prototype._add_cleanup = function(callback) {        this.cleanup_callbacks.push(callback);    };    /**     * Schedule a function to be run after the test result is known, regardless     * of passing or failing state.     *     * The behavior of this function will not     * influence the result of the test, but if an exception is thrown, the     * test harness will report an error.     *     * @param {Function} callback - The cleanup function to run. This     * is called with no arguments.     */    Test.prototype.add_cleanup = function(callback) {        this._user_defined_cleanup_count += 1;        this._add_cleanup(callback);    };    Test.prototype.set_timeout = function()    {        if (this.timeout_length !== null) {            var this_obj = this;            this.timeout_id = setTimeout(function()                                         {                                             this_obj.timeout();                                         }, this.timeout_length);        }    };    Test.prototype.set_status = function(status, message, stack)    {        this.status = status;        this.message = message;        this.stack = stack ? stack : null;    };    /**     * Manually set the test status to ``TIMEOUT``.     */    Test.prototype.timeout = function()    {        this.timeout_id = null;        this.set_status(this.TIMEOUT, "Test timed out");        this.phase = this.phases.HAS_RESULT;        this.done();    };    /**     * Manually set the test status to ``TIMEOUT``.     *     * Alias for `Test.timeout <#Test.timeout>`_.     */    Test.prototype.force_timeout = function() {        return this.timeout();    };    /**     * Mark the test as complete.     *     * This sets the test status to ``PASS`` if no other status was     * already recorded. Any subsequent attempts to run additional     * test steps will be ignored.     *     * After setting the test status any test cleanup functions will     * be run.     */    Test.prototype.done = function()    {        if (this.phase >= this.phases.CLEANING) {            return;        }        if (this.phase <= this.phases.STARTED) {            this.set_status(this.PASS, null);        }        if (global_scope.clearTimeout) {            clearTimeout(this.timeout_id);        }        if (settings.debug) {            console.log("TEST DONE",                        this.status,                        this.name);        }        this.cleanup();    };    function add_test_done_callback(test, callback)    {        if (test.phase === test.phases.COMPLETE) {            callback();            return;        }        test._done_callbacks.push(callback);    }    /*     * Invoke all specified cleanup functions. If one or more produce an error,     * the context is in an unpredictable state, so all further testing should     * be cancelled.     */    Test.prototype.cleanup = function() {        var errors = [];        var bad_value_count = 0;        function on_error(e) {            errors.push(e);            // Abort tests immediately so that tests declared within subsequent            // cleanup functions are not run.            tests.abort();        }        var this_obj = this;        var results = [];        this.phase = this.phases.CLEANING;        forEach(this.cleanup_callbacks,                function(cleanup_callback) {                    var result;                    try {                        result = cleanup_callback();                    } catch (e) {                        on_error(e);                        return;                    }                    if (!is_valid_cleanup_result(this_obj, result)) {                        bad_value_count += 1;                        // Abort tests immediately so that tests declared                        // within subsequent cleanup functions are not run.                        tests.abort();                    }                    results.push(result);                });        if (!this._is_promise_test) {            cleanup_done(this_obj, errors, bad_value_count);        } else {            all_async(results,                      function(result, done) {                          if (result && typeof result.then === "function") {                              result                                  .then(null, on_error)                                  .then(done);                          } else {                              done();                          }                      },                      function() {                          cleanup_done(this_obj, errors, bad_value_count);                      });        }    };    /*     * Determine if the return value of a cleanup function is valid for a given     * test. Any test may return the value `undefined`. Tests created with     * `promise_test` may alternatively return "thenable" object values.     */    function is_valid_cleanup_result(test, result) {        if (result === undefined) {            return true;        }        if (test._is_promise_test) {            return result && typeof result.then === "function";        }        return false;    }    function cleanup_done(test, errors, bad_value_count) {        if (errors.length || bad_value_count) {            var total = test._user_defined_cleanup_count;            tests.status.status = tests.status.ERROR;            tests.status.stack = null;            tests.status.message = "Test named '" + test.name +                "' specified " + total +                " 'cleanup' function" + (total > 1 ? "s" : "");            if (errors.length) {                tests.status.message += ", and " + errors.length + " failed";                tests.status.stack = ((typeof errors[0] === "object" &&                                       errors[0].hasOwnProperty("stack")) ?                                      errors[0].stack : null);            }            if (bad_value_count) {                var type = test._is_promise_test ?                   "non-thenable" : "non-undefined";                tests.status.message += ", and " + bad_value_count +                    " returned a " + type + " value";            }            tests.status.message += ".";        }        test.phase = test.phases.COMPLETE;        tests.result(test);        forEach(test._done_callbacks,                function(callback) {                    callback();                });        test._done_callbacks.length = 0;    }    /**     * A RemoteTest object mirrors a Test object on a remote worker. The     * associated RemoteWorker updates the RemoteTest object in response to     * received events. In turn, the RemoteTest object replicates these events     * on the local document. This allows listeners (test result reporting     * etc..) to transparently handle local and remote events.     */    function RemoteTest(clone) {        var this_obj = this;        Object.keys(clone).forEach(                function(key) {                    this_obj[key] = clone[key];                });        this.index = null;        this.phase = this.phases.INITIAL;        this.update_state_from(clone);        this._done_callbacks = [];        tests.push(this);    }    RemoteTest.prototype.structured_clone = function() {        var clone = {};        Object.keys(this).forEach(                (function(key) {                    var value = this[key];                    // `RemoteTest` instances are responsible for managing                    // their own "done" callback functions, so those functions                    // are not relevant in other execution contexts. Because of                    // this (and because Function values cannot be serialized                    // for cross-realm transmittance), the property should not                    // be considered when cloning instances.                    if (key === '_done_callbacks' ) {                        return;                    }                    if (typeof value === "object" && value !== null) {                        clone[key] = merge({}, value);                    } else {                        clone[key] = value;                    }                }).bind(this));        clone.phases = merge({}, this.phases);        return clone;    };    /**     * `RemoteTest` instances are objects which represent tests running in     * another realm. They do not define "cleanup" functions (if necessary,     * such functions are defined on the associated `Test` instance within the     * external realm). However, `RemoteTests` may have "done" callbacks (e.g.     * as attached by the `Tests` instance responsible for tracking the overall     * test status in the parent realm). The `cleanup` method delegates to     * `done` in order to ensure that such callbacks are invoked following the     * completion of the `RemoteTest`.     */    RemoteTest.prototype.cleanup = function() {        this.done();    };    RemoteTest.prototype.phases = Test.prototype.phases;    RemoteTest.prototype.update_state_from = function(clone) {        this.status = clone.status;        this.message = clone.message;        this.stack = clone.stack;        if (this.phase === this.phases.INITIAL) {            this.phase = this.phases.STARTED;        }    };    RemoteTest.prototype.done = function() {        this.phase = this.phases.COMPLETE;        forEach(this._done_callbacks,                function(callback) {                    callback();                });    }    RemoteTest.prototype.format_status = function() {        return Test.prototype.status_formats[this.status];    }    /*     * A RemoteContext listens for test events from a remote test context, such     * as another window or a worker. These events are then used to construct     * and maintain RemoteTest objects that mirror the tests running in the     * remote context.     *     * An optional third parameter can be used as a predicate to filter incoming     * MessageEvents.     */    function RemoteContext(remote, message_target, message_filter) {        this.running = true;        this.started = false;        this.tests = new Array();        this.early_exception = null;        var this_obj = this;        // If remote context is cross origin assigning to onerror is not        // possible, so silently catch those errors.        try {          remote.onerror = function(error) { this_obj.remote_error(error); };        } catch (e) {          // Ignore.        }        // Keeping a reference to the remote object and the message handler until        // remote_done() is seen prevents the remote object and its message channel        // from going away before all the messages are dispatched.        this.remote = remote;        this.message_target = message_target;        this.message_handler = function(message) {            var passesFilter = !message_filter || message_filter(message);            // The reference to the `running` property in the following            // condition is unnecessary because that value is only set to            // `false` after the `message_handler` function has been            // unsubscribed.            // TODO: Simplify the condition by removing the reference.            if (this_obj.running && message.data && passesFilter &&                (message.data.type in this_obj.message_handlers)) {                this_obj.message_handlers[message.data.type].call(this_obj, message.data);            }        };        if (self.Promise) {            this.done = new Promise(function(resolve) {                this_obj.doneResolve = resolve;            });        }        this.message_target.addEventListener("message", this.message_handler);    }    RemoteContext.prototype.remote_error = function(error) {        if (error.preventDefault) {            error.preventDefault();        }        // Defer interpretation of errors until the testing protocol has        // started and the remote test's `allow_uncaught_exception` property        // is available.        if (!this.started) {            this.early_exception = error;        } else if (!this.allow_uncaught_exception) {            this.report_uncaught(error);        }    };    RemoteContext.prototype.report_uncaught = function(error) {        var message = error.message || String(error);        var filename = (error.filename ? " " + error.filename: "");        // FIXME: Display remote error states separately from main document        // error state.        tests.set_status(tests.status.ERROR,                         "Error in remote" + filename + ": " + message,                         error.stack);    };    RemoteContext.prototype.start = function(data) {        this.started = true;        this.allow_uncaught_exception = data.properties.allow_uncaught_exception;        if (this.early_exception && !this.allow_uncaught_exception) {            this.report_uncaught(this.early_exception);        }    };    RemoteContext.prototype.test_state = function(data) {        var remote_test = this.tests[data.test.index];        if (!remote_test) {            remote_test = new RemoteTest(data.test);            this.tests[data.test.index] = remote_test;        }        remote_test.update_state_from(data.test);        tests.notify_test_state(remote_test);    };    RemoteContext.prototype.test_done = function(data) {        var remote_test = this.tests[data.test.index];        remote_test.update_state_from(data.test);        remote_test.done();        tests.result(remote_test);    };    RemoteContext.prototype.remote_done = function(data) {        if (tests.status.status === null &&            data.status.status !== data.status.OK) {            tests.set_status(data.status.status, data.status.message, data.status.stack);        }        for (let assert of data.asserts) {            var record = new AssertRecord();            record.assert_name = assert.assert_name;            record.args = assert.args;            record.test = assert.test != null ? this.tests[assert.test.index] : null;            record.status = assert.status;            record.stack = assert.stack;            tests.asserts_run.push(record);        }        this.message_target.removeEventListener("message", this.message_handler);        this.running = false;        // If remote context is cross origin assigning to onerror is not        // possible, so silently catch those errors.        try {          this.remote.onerror = null;        } catch (e) {          // Ignore.        }        this.remote = null;        this.message_target = null;        if (this.doneResolve) {            this.doneResolve();        }        if (tests.all_done()) {            tests.complete();        }    };    RemoteContext.prototype.message_handlers = {        start: RemoteContext.prototype.start,        test_state: RemoteContext.prototype.test_state,        result: RemoteContext.prototype.test_done,        complete: RemoteContext.prototype.remote_done    };    /**     * @class     * Status of the overall harness     */    function TestsStatus()    {        /** The status code */        this.status = null;        /** Message in case of failure */        this.message = null;        /** Stack trace in case of an exception. */        this.stack = null;    }    /**     * Enum of possible harness statuses.     *     * :values:     *   - ``OK``     *   - ``ERROR``     *   - ``TIMEOUT``     *   - ``PRECONDITION_FAILED``     */    TestsStatus.statuses = {        OK:0,        ERROR:1,        TIMEOUT:2,        PRECONDITION_FAILED:3    };    TestsStatus.prototype = merge({}, TestsStatus.statuses);    TestsStatus.prototype.formats = {        0: "OK",        1: "Error",        2: "Timeout",        3: "Optional Feature Unsupported"    };    TestsStatus.prototype.structured_clone = function()    {        if (!this._structured_clone) {            var msg = this.message;            msg = msg ? String(msg) : msg;            this._structured_clone = merge({                status:this.status,                message:msg,                stack:this.stack            }, TestsStatus.statuses);        }        return this._structured_clone;    };    TestsStatus.prototype.format_status = function() {        return this.formats[this.status];    };    /**     * @class     * Record of an assert that ran.     *     * @param {Test} test - The test which ran the assert.     * @param {string} assert_name - The function name of the assert.     * @param {Any} args - The arguments passed to the assert function.     */    function AssertRecord(test, assert_name, args = []) {        /** Name of the assert that ran */        this.assert_name = assert_name;        /** Test that ran the assert */        this.test = test;        // Avoid keeping complex objects alive        /** Stringification of the arguments that were passed to the assert function */        this.args = args.map(x => format_value(x).replace(/\n/g, " "));        /** Status of the assert */        this.status = null;    }    AssertRecord.prototype.structured_clone = function() {        return {            assert_name: this.assert_name,            test: this.test ? this.test.structured_clone() : null,            args: this.args,            status: this.status,        };    };    function Tests()    {        this.tests = [];        this.num_pending = 0;        this.phases = {            INITIAL:0,            SETUP:1,            HAVE_TESTS:2,            HAVE_RESULTS:3,            COMPLETE:4        };        this.phase = this.phases.INITIAL;        this.properties = {};        this.wait_for_finish = false;        this.processing_callbacks = false;        this.allow_uncaught_exception = false;        this.file_is_test = false;        // This value is lazily initialized in order to avoid introducing a        // dependency on ECMAScript 2015 Promises to all tests.        this.promise_tests = null;        this.promise_setup_called = false;        this.timeout_multiplier = 1;        this.timeout_length = test_environment.test_timeout();        this.timeout_id = null;        this.start_callbacks = [];        this.test_state_callbacks = [];        this.test_done_callbacks = [];        this.all_done_callbacks = [];        this.hide_test_state = false;        this.pending_remotes = [];        this.current_test = null;        this.asserts_run = [];        // Track whether output is enabled, and thus whether or not we should        // track asserts.        //        // On workers we don't get properties set from testharnessreport.js, so        // we don't know whether or not to track asserts. To avoid the        // resulting performance hit, we assume we are not meant to. This means        // that assert tracking does not function on workers.        this.output = settings.output && 'document' in global_scope;        this.status = new TestsStatus();        var this_obj = this;        test_environment.add_on_loaded_callback(function() {            if (this_obj.all_done()) {                this_obj.complete();            }        });        this.set_timeout();    }    Tests.prototype.setup = function(func, properties)    {        if (this.phase >= this.phases.HAVE_RESULTS) {            return;        }        if (this.phase < this.phases.SETUP) {            this.phase = this.phases.SETUP;        }        this.properties = properties;        for (var p in properties) {            if (properties.hasOwnProperty(p)) {                var value = properties[p];                if (p == "allow_uncaught_exception") {                    this.allow_uncaught_exception = value;                } else if (p == "explicit_done" && value) {                    this.wait_for_finish = true;                } else if (p == "explicit_timeout" && value) {                    this.timeout_length = null;                    if (this.timeout_id)                    {                        clearTimeout(this.timeout_id);                    }                } else if (p == "single_test" && value) {                    this.set_file_is_test();                } else if (p == "timeout_multiplier") {                    this.timeout_multiplier = value;                    if (this.timeout_length) {                         this.timeout_length *= this.timeout_multiplier;                    }                } else if (p == "hide_test_state") {                    this.hide_test_state = value;                } else if (p == "output") {                    this.output = value;                } else if (p === "debug") {                    settings.debug = value;                }            }        }        if (func) {            try {                func();            } catch (e) {                this.status.status = e instanceof OptionalFeatureUnsupportedError ? this.status.PRECONDITION_FAILED : this.status.ERROR;                this.status.message = String(e);                this.status.stack = e.stack ? e.stack : null;                this.complete();            }        }        this.set_timeout();    };    Tests.prototype.set_file_is_test = function() {        if (this.tests.length > 0) {            throw new Error("Tried to set file as test after creating a test");        }        this.wait_for_finish = true;        this.file_is_test = true;        // Create the test, which will add it to the list of tests        tests.current_test = async_test();    };    Tests.prototype.set_status = function(status, message, stack)    {        this.status.status = status;        this.status.message = message;        this.status.stack = stack ? stack : null;    };    Tests.prototype.set_timeout = function() {        if (global_scope.clearTimeout) {            var this_obj = this;            clearTimeout(this.timeout_id);            if (this.timeout_length !== null) {                this.timeout_id = setTimeout(function() {                                                 this_obj.timeout();                                             }, this.timeout_length);            }        }    };    Tests.prototype.timeout = function() {        var test_in_cleanup = null;        if (this.status.status === null) {            forEach(this.tests,                    function(test) {                        // No more than one test is expected to be in the                        // "CLEANUP" phase at any time                        if (test.phase === test.phases.CLEANING) {                            test_in_cleanup = test;                        }                        test.phase = test.phases.COMPLETE;                    });            // Timeouts that occur while a test is in the "cleanup" phase            // indicate that some global state was not properly reverted. This            // invalidates the overall test execution, so the timeout should be            // reported as an error and cancel the execution of any remaining            // tests.            if (test_in_cleanup) {                this.status.status = this.status.ERROR;                this.status.message = "Timeout while running cleanup for " +                    "test named \"" + test_in_cleanup.name + "\".";                tests.status.stack = null;            } else {                this.status.status = this.status.TIMEOUT;            }        }        this.complete();    };    Tests.prototype.end_wait = function()    {        this.wait_for_finish = false;        if (this.all_done()) {            this.complete();        }    };    Tests.prototype.push = function(test)    {        if (this.phase < this.phases.HAVE_TESTS) {            this.start();        }        this.num_pending++;        test.index = this.tests.push(test);        this.notify_test_state(test);    };    Tests.prototype.notify_test_state = function(test) {        var this_obj = this;        forEach(this.test_state_callbacks,                function(callback) {                    callback(test, this_obj);                });    };    Tests.prototype.all_done = function() {        return (this.tests.length > 0 || this.pending_remotes.length > 0) &&                test_environment.all_loaded &&                (this.num_pending === 0 || this.is_aborted) && !this.wait_for_finish &&                !this.processing_callbacks &&                !this.pending_remotes.some(function(w) { return w.running; });    };    Tests.prototype.start = function() {        this.phase = this.phases.HAVE_TESTS;        this.notify_start();    };    Tests.prototype.notify_start = function() {        var this_obj = this;        forEach (this.start_callbacks,                 function(callback)                 {                     callback(this_obj.properties);                 });    };    Tests.prototype.result = function(test)    {        // If the harness has already transitioned beyond the `HAVE_RESULTS`        // phase, subsequent tests should not cause it to revert.        if (this.phase <= this.phases.HAVE_RESULTS) {            this.phase = this.phases.HAVE_RESULTS;        }        this.num_pending--;        this.notify_result(test);    };    Tests.prototype.notify_result = function(test) {        var this_obj = this;        this.processing_callbacks = true;        forEach(this.test_done_callbacks,                function(callback)                {                    callback(test, this_obj);                });        this.processing_callbacks = false;        if (this_obj.all_done()) {            this_obj.complete();        }    };    Tests.prototype.complete = function() {        if (this.phase === this.phases.COMPLETE) {            return;        }        var this_obj = this;        var all_complete = function() {            this_obj.phase = this_obj.phases.COMPLETE;            this_obj.notify_complete();        };        var incomplete = filter(this.tests,                                function(test) {                                    return test.phase < test.phases.COMPLETE;                                });        /**         * To preserve legacy behavior, overall test completion must be         * signaled synchronously.         */        if (incomplete.length === 0) {            all_complete();            return;        }        all_async(incomplete,                  function(test, testDone)                  {                      if (test.phase === test.phases.INITIAL) {                          test.phase = test.phases.COMPLETE;                          testDone();                      } else {                          add_test_done_callback(test, testDone);                          test.cleanup();                      }                  },                  all_complete);    };    Tests.prototype.set_assert = function(assert_name, args) {        this.asserts_run.push(new AssertRecord(this.current_test, assert_name, args))    }    Tests.prototype.set_assert_status = function(status, stack) {        let assert_record = this.asserts_run[this.asserts_run.length - 1];        assert_record.status = status;        assert_record.stack = stack;    }    /**     * Update the harness status to reflect an unrecoverable harness error that     * should cancel all further testing. Update all previously-defined tests     * which have not yet started to indicate that they will not be executed.     */    Tests.prototype.abort = function() {        this.status.status = this.status.ERROR;        this.is_aborted = true;        forEach(this.tests,                function(test) {                    if (test.phase === test.phases.INITIAL) {                        test.phase = test.phases.COMPLETE;                    }                });    };    /*     * Determine if any tests share the same `name` property. Return an array     * containing the names of any such duplicates.     */    Tests.prototype.find_duplicates = function() {        var names = Object.create(null);        var duplicates = [];        forEach (this.tests,                 function(test)                 {                     if (test.name in names && duplicates.indexOf(test.name) === -1) {                        duplicates.push(test.name);                     }                     names[test.name] = true;                 });        return duplicates;    };    function code_unit_str(char) {        return 'U+' + char.charCodeAt(0).toString(16);    }    function sanitize_unpaired_surrogates(str) {        return str.replace(            /([\ud800-\udbff]+)(?![\udc00-\udfff])|(^|[^\ud800-\udbff])([\udc00-\udfff]+)/g,            function(_, low, prefix, high) {                var output = prefix || "";  // prefix may be undefined                var string = low || high;  // only one of these alternates can match                for (var i = 0; i < string.length; i++) {                    output += code_unit_str(string[i]);                }                return output;            });    }    function sanitize_all_unpaired_surrogates(tests) {        forEach (tests,                 function (test)                 {                     var sanitized = sanitize_unpaired_surrogates(test.name);                     if (test.name !== sanitized) {                         test.name = sanitized;                         delete test._structured_clone;                     }                 });    }    Tests.prototype.notify_complete = function() {        var this_obj = this;        var duplicates;        if (this.status.status === null) {            duplicates = this.find_duplicates();            // Some transports adhere to UTF-8's restriction on unpaired            // surrogates. Sanitize the titles so that the results can be            // consistently sent via all transports.            sanitize_all_unpaired_surrogates(this.tests);            // Test names are presumed to be unique within test files--this            // allows consumers to use them for identification purposes.            // Duplicated names violate this expectation and should therefore            // be reported as an error.            if (duplicates.length) {                this.status.status = this.status.ERROR;                this.status.message =                   duplicates.length + ' duplicate test name' +                   (duplicates.length > 1 ? 's' : '') + ': "' +                   duplicates.join('", "') + '"';            } else {                this.status.status = this.status.OK;            }        }        forEach (this.all_done_callbacks,                 function(callback)                 {                     callback(this_obj.tests, this_obj.status, this_obj.asserts_run);                 });    };    /*     * Constructs a RemoteContext that tracks tests from a specific worker.     */    Tests.prototype.create_remote_worker = function(worker) {        var message_port;        if (is_service_worker(worker)) {            message_port = navigator.serviceWorker;            worker.postMessage({type: "connect"});        } else if (is_shared_worker(worker)) {            message_port = worker.port;            message_port.start();        } else {            message_port = worker;        }        return new RemoteContext(worker, message_port);    };    /*     * Constructs a RemoteContext that tracks tests from a specific window.     */    Tests.prototype.create_remote_window = function(remote) {        // BUG: CWE-345: Insufficient Verification of Data Authenticity// remote.postMessage({type: "getmessages"}, "*");// FIXED:         return new RemoteContext(            remote,            window,            function(msg) {                return msg.source === remote;            }        );    };    Tests.prototype.fetch_tests_from_worker = function(worker) {        if (this.phase >= this.phases.COMPLETE) {            return;        }        var remoteContext = this.create_remote_worker(worker);        this.pending_remotes.push(remoteContext);        return remoteContext.done;    };    /**     * Get test results from a worker and include them in the current test.     *     * @param {Worker|SharedWorker|ServiceWorker|MessagePort} port -     * Either a worker object or a port connected to a worker which is     * running tests..     * @returns {Promise} - A promise that's resolved once all the remote tests are complete.     */    function fetch_tests_from_worker(port) {        return tests.fetch_tests_from_worker(port);    }    expose(fetch_tests_from_worker, 'fetch_tests_from_worker');    Tests.prototype.fetch_tests_from_window = function(remote) {        if (this.phase >= this.phases.COMPLETE) {            return;        }        this.pending_remotes.push(this.create_remote_window(remote));    };    /**     * Aggregate tests from separate windows or iframes     * into the current document as if they were all part of the same test file.     *     * The document of the second window (or iframe) should include     * ``testharness.js``, but not ``testharnessreport.js``, and use     * :js:func:`test`, :js:func:`async_test`, and :js:func:`promise_test` in     * the usual manner.     *     * @param {Window} window - The window to fetch tests from.     */    function fetch_tests_from_window(window) {        tests.fetch_tests_from_window(window);    }    expose(fetch_tests_from_window, 'fetch_tests_from_window');    /**     * Get test results from a shadow realm and include them in the current test.     *     * @param {ShadowRealm} realm - A shadow realm also running the test harness     * @returns {Promise} - A promise that's resolved once all the remote tests are complete.     */    function fetch_tests_from_shadow_realm(realm) {        var chan = new MessageChannel();        function receiveMessage(msg_json) {            chan.port1.postMessage(JSON.parse(msg_json));        }        var done = tests.fetch_tests_from_worker(chan.port2);        realm.evaluate("begin_shadow_realm_tests")(receiveMessage);        chan.port2.start();        return done;    }    expose(fetch_tests_from_shadow_realm, 'fetch_tests_from_shadow_realm');    /**     * Begin running tests in this shadow realm test harness.     *     * To be called after all tests have been loaded; it is an error to call     * this more than once or in a non-Shadow Realm environment     *     * @param {Function} postMessage - A function to send test updates to the     * incubating realm-- accepts JSON-encoded messages in the format used by     * RemoteContext     */    function begin_shadow_realm_tests(postMessage) {        if (!(test_environment instanceof ShadowRealmTestEnvironment)) {            throw new Error("beign_shadow_realm_tests called in non-Shadow Realm environment");        }        test_environment.begin(function (msg) {            postMessage(JSON.stringify(msg));        });    }    expose(begin_shadow_realm_tests, 'begin_shadow_realm_tests');    /**     * Timeout the tests.     *     * This only has an effect when ``explicit_timeout`` has been set     * in :js:func:`setup`. In other cases any call is a no-op.     *     */    function timeout() {        if (tests.timeout_length === null) {            tests.timeout();        }    }    expose(timeout, 'timeout');    /**     * Add a callback that's triggered when the first :js:class:`Test` is created.     *     * @param {Function} callback - Callback function. This is called     * without arguments.     */    function add_start_callback(callback) {        tests.start_callbacks.push(callback);    }    /**     * Add a callback that's triggered when a test state changes.     *     * @param {Function} callback - Callback function, called with the     * :js:class:`Test` as the only argument.     */    function add_test_state_callback(callback) {        tests.test_state_callbacks.push(callback);    }    /**     * Add a callback that's triggered when a test result is received.     *     * @param {Function} callback - Callback function, called with the     * :js:class:`Test` as the only argument.     */    function add_result_callback(callback) {        tests.test_done_callbacks.push(callback);    }    /**     * Add a callback that's triggered when all tests are complete.     *     * @param {Function} callback - Callback function, called with an     * array of :js:class:`Test` objects, a :js:class:`TestsStatus`     * object and an array of :js:class:`AssertRecord` objects. If the     * debug setting is ``false`` the final argument will be an empty     * array.     *     * For performance reasons asserts are only tracked when the debug     * setting is ``true``. In other cases the array of asserts will be     * empty.     */    function add_completion_callback(callback) {        tests.all_done_callbacks.push(callback);    }    expose(add_start_callback, 'add_start_callback');    expose(add_test_state_callback, 'add_test_state_callback');    expose(add_result_callback, 'add_result_callback');    expose(add_completion_callback, 'add_completion_callback');    function remove(array, item) {        var index = array.indexOf(item);        if (index > -1) {            array.splice(index, 1);        }    }    function remove_start_callback(callback) {        remove(tests.start_callbacks, callback);    }    function remove_test_state_callback(callback) {        remove(tests.test_state_callbacks, callback);    }    function remove_result_callback(callback) {        remove(tests.test_done_callbacks, callback);    }    function remove_completion_callback(callback) {       remove(tests.all_done_callbacks, callback);    }    /*     * Output listener    */    function Output() {        this.output_document = document;        this.output_node = null;        this.enabled = settings.output;        this.phase = this.INITIAL;    }    Output.prototype.INITIAL = 0;    Output.prototype.STARTED = 1;    Output.prototype.HAVE_RESULTS = 2;    Output.prototype.COMPLETE = 3;    Output.prototype.setup = function(properties) {        if (this.phase > this.INITIAL) {            return;        }        //If output is disabled in testharnessreport.js the test shouldn't be        //able to override that        this.enabled = this.enabled && (properties.hasOwnProperty("output") ?                                        properties.output : settings.output);    };    Output.prototype.init = function(properties) {        if (this.phase >= this.STARTED) {            return;        }        if (properties.output_document) {            this.output_document = properties.output_document;        } else {            this.output_document = document;        }        this.phase = this.STARTED;    };    Output.prototype.resolve_log = function() {        var output_document;        if (this.output_node) {            return;        }        if (typeof this.output_document === "function") {            output_document = this.output_document.apply(undefined);        } else {            output_document = this.output_document;        }        if (!output_document) {            return;        }        var node = output_document.getElementById("log");        if (!node) {            if (output_document.readyState === "loading") {                return;            }            node = output_document.createElementNS("http://www.w3.org/1999/xhtml", "div");            node.id = "log";            if (output_document.body) {                output_document.body.appendChild(node);            } else {                var root = output_document.documentElement;                var is_html = (root &&                               root.namespaceURI == "http://www.w3.org/1999/xhtml" &&                               root.localName == "html");                var is_svg = (output_document.defaultView &&                              "SVGSVGElement" in output_document.defaultView &&                              root instanceof output_document.defaultView.SVGSVGElement);                if (is_svg) {                    var foreignObject = output_document.createElementNS("http://www.w3.org/2000/svg", "foreignObject");                    foreignObject.setAttribute("width", "100%");                    foreignObject.setAttribute("height", "100%");                    root.appendChild(foreignObject);                    foreignObject.appendChild(node);                } else if (is_html) {                    root.appendChild(output_document.createElementNS("http://www.w3.org/1999/xhtml", "body"))                        .appendChild(node);                } else {                    root.appendChild(node);                }            }        }        this.output_document = output_document;        this.output_node = node;    };    Output.prototype.show_status = function() {        if (this.phase < this.STARTED) {            this.init({});        }        if (!this.enabled || this.phase === this.COMPLETE) {            return;        }        this.resolve_log();        if (this.phase < this.HAVE_RESULTS) {            this.phase = this.HAVE_RESULTS;        }        var done_count = tests.tests.length - tests.num_pending;        if (this.output_node && !tests.hide_test_state) {            if (done_count < 100 ||                (done_count < 1000 && done_count % 100 === 0) ||                done_count % 1000 === 0) {                this.output_node.textContent = "Running, " +                    done_count + " complete, " +                    tests.num_pending + " remain";            }        }    };    Output.prototype.show_results = function (tests, harness_status, asserts_run) {        if (this.phase >= this.COMPLETE) {            return;        }        if (!this.enabled) {            return;        }        if (!this.output_node) {            this.resolve_log();        }        this.phase = this.COMPLETE;        var log = this.output_node;        if (!log) {            return;        }        var output_document = this.output_document;        while (log.lastChild) {            log.removeChild(log.lastChild);        }        var stylesheet = output_document.createElementNS(xhtml_ns, "style");        stylesheet.textContent = stylesheetContent;        var heads = output_document.getElementsByTagName("head");        if (heads.length) {            heads[0].appendChild(stylesheet);        }        var status_number = {};        forEach(tests,                function(test) {                    var status = test.format_status();                    if (status_number.hasOwnProperty(status)) {                        status_number[status] += 1;                    } else {                        status_number[status] = 1;                    }                });        function status_class(status)        {            return status.replace(/\s/g, '').toLowerCase();        }        var summary_template = ["section", {"id":"summary"},                                ["h2", {}, "Summary"],                                function()                                {                                    var status = harness_status.format_status();                                    var rv = [["section", {},                                               ["p", {},                                                "Harness status: ",                                                ["span", {"class":status_class(status)},                                                 status                                                ],                                               ],                                               ["button",                                                {"onclick": "let evt = new Event('__test_restart'); " +                                                 "let canceled = !window.dispatchEvent(evt);" +                                                 "if (!canceled) { location.reload() }"},                                                "Rerun"]                                              ]];                                    if (harness_status.status === harness_status.ERROR) {                                        rv[0].push(["pre", {}, harness_status.message]);                                        if (harness_status.stack) {                                            rv[0].push(["pre", {}, harness_status.stack]);                                        }                                    }                                    return rv;                                },                                ["p", {}, "Found ${num_tests} tests"],                                function() {                                    var rv = [["div", {}]];                                    var i = 0;                                    while (Test.prototype.status_formats.hasOwnProperty(i)) {                                        if (status_number.hasOwnProperty(Test.prototype.status_formats[i])) {                                            var status = Test.prototype.status_formats[i];                                            rv[0].push(["div", {},                                                        ["label", {},                                                         ["input", {type:"checkbox", checked:"checked"}],                                                         status_number[status] + " ",                                                         ["span", {"class":status_class(status)}, status]]]);                                        }                                        i++;                                    }                                    return rv;                                },                               ];        log.appendChild(render(summary_template, {num_tests:tests.length}, output_document));        forEach(output_document.querySelectorAll("section#summary label"),                function(element)                {                    on_event(element, "click",                             function(e)                             {                                 if (output_document.getElementById("results") === null) {                                     e.preventDefault();                                     return;                                 }                                 var result_class = element.querySelector("span[class]").getAttribute("class");                                 var style_element = output_document.querySelector("style#hide-" + result_class);                                 var input_element = element.querySelector("input");                                 if (!style_element && !input_element.checked) {                                     style_element = output_document.createElementNS(xhtml_ns, "style");                                     style_element.id = "hide-" + result_class;                                     style_element.textContent = "table#results > tbody > tr.overall-"+result_class+"{display:none}";                                     output_document.body.appendChild(style_element);                                 } else if (style_element && input_element.checked) {                                     style_element.parentNode.removeChild(style_element);                                 }                             });                });        // This use of innerHTML plus manual escaping is not recommended in        // general, but is necessary here for performance.  Using textContent        // on each individual <td> adds tens of seconds of execution time for        // large test suites (tens of thousands of tests).        function escape_html(s)        {            return s.replace(/\&/g, "&amp;")                .replace(/</g, "&lt;")                .replace(/"/g, "&quot;")                .replace(/'/g, "&#39;");        }        function has_assertions()        {            for (var i = 0; i < tests.length; i++) {                if (tests[i].properties.hasOwnProperty("assert")) {                    return true;                }            }            return false;        }        function get_assertion(test)        {            if (test.properties.hasOwnProperty("assert")) {                if (Array.isArray(test.properties.assert)) {                    return test.properties.assert.join(' ');                }                return test.properties.assert;            }            return '';        }        var asserts_run_by_test = new Map();        asserts_run.forEach(assert => {            if (!asserts_run_by_test.has(assert.test)) {                asserts_run_by_test.set(assert.test, []);            }            asserts_run_by_test.get(assert.test).push(assert);        });        function get_asserts_output(test) {            var asserts = asserts_run_by_test.get(test);            if (!asserts) {                return "No asserts ran";            }            rv = "<table>";            rv += asserts.map(assert => {                var output_fn = "<strong>" + escape_html(assert.assert_name) + "</strong>(";                var prefix_len = output_fn.length;                var output_args = assert.args;                var output_len = output_args.reduce((prev, current) => prev+current, prefix_len);                if (output_len[output_len.length - 1] > 50) {                    output_args = output_args.map((x, i) =>                    (i > 0 ? "  ".repeat(prefix_len) : "" )+ x + (i < output_args.length - 1 ? ",\n" : ""));                } else {                    output_args = output_args.map((x, i) => x + (i < output_args.length - 1 ? ", " : ""));                }                output_fn += escape_html(output_args.join(""));                output_fn += ')';                var output_location;                if (assert.stack) {                    output_location = assert.stack.split("\n", 1)[0].replace(/@?\w+:\/\/[^ "\/]+(?::\d+)?/g, " ");                }                return "<tr class='overall-" +                    status_class(Test.prototype.status_formats[assert.status]) + "'>" +                    "<td class='" +                    status_class(Test.prototype.status_formats[assert.status]) + "'>" +                    Test.prototype.status_formats[assert.status] + "</td>" +                    "<td><pre>" +                    output_fn +                    (output_location ? "\n" + escape_html(output_location) : "") +                    "</pre></td></tr>";            }            ).join("\n");            rv += "</table>";            return rv;        }        log.appendChild(document.createElementNS(xhtml_ns, "section"));        var assertions = has_assertions();        var html = "<h2>Details</h2><table id='results' " + (assertions ? "class='assertions'" : "" ) + ">" +            "<thead><tr><th>Result</th><th>Test Name</th>" +            (assertions ? "<th>Assertion</th>" : "") +            "<th>Message</th></tr></thead>" +            "<tbody>";        for (var i = 0; i < tests.length; i++) {            var test = tests[i];            html += '<tr class="overall-' +                status_class(test.format_status()) +                '">' +                '<td class="' +                status_class(test.format_status()) +                '">' +                test.format_status() +                "</td><td>" +                escape_html(test.name) +                "</td><td>" +                (assertions ? escape_html(get_assertion(test)) + "</td><td>" : "") +                escape_html(test.message ? tests[i].message : " ") +                (tests[i].stack ? "<pre>" +                 escape_html(tests[i].stack) +                 "</pre>": "");            if (!(test instanceof RemoteTest)) {                 html += "<details><summary>Asserts run</summary>" + get_asserts_output(test) + "</details>"            }            html += "</td></tr>";        }        html += "</tbody></table>";        try {            log.lastChild.innerHTML = html;        } catch (e) {            log.appendChild(document.createElementNS(xhtml_ns, "p"))               .textContent = "Setting innerHTML for the log threw an exception.";            log.appendChild(document.createElementNS(xhtml_ns, "pre"))               .textContent = html;        }    };    /*     * Template code     *     * A template is just a JavaScript structure. An element is represented as:     *     * [tag_name, {attr_name:attr_value}, child1, child2]     *     * the children can either be strings (which act like text nodes), other templates or     * functions (see below)     *     * A text node is represented as     *     * ["{text}", value]     *     * String values have a simple substitution syntax; ${foo} represents a variable foo.     *     * It is possible to embed logic in templates by using a function in a place where a     * node would usually go. The function must either return part of a template or null.     *     * In cases where a set of nodes are required as output rather than a single node     * with children it is possible to just use a list     * [node1, node2, node3]     *     * Usage:     *     * render(template, substitutions) - take a template and an object mapping     * variable names to parameters and return either a DOM node or a list of DOM nodes     *     * substitute(template, substitutions) - take a template and variable mapping object,     * make the variable substitutions and return the substituted template     *     */    function is_single_node(template)    {        return typeof template[0] === "string";    }    function substitute(template, substitutions)    {        if (typeof template === "function") {            var replacement = template(substitutions);            if (!replacement) {                return null;            }            return substitute(replacement, substitutions);        }        if (is_single_node(template)) {            return substitute_single(template, substitutions);        }        return filter(map(template, function(x) {                              return substitute(x, substitutions);                          }), function(x) {return x !== null;});    }    function substitute_single(template, substitutions)    {        var substitution_re = /\$\{([^ }]*)\}/g;        function do_substitution(input) {            var components = input.split(substitution_re);            var rv = [];            for (var i = 0; i < components.length; i += 2) {                rv.push(components[i]);                if (components[i + 1]) {                    rv.push(String(substitutions[components[i + 1]]));                }            }            return rv;        }        function substitute_attrs(attrs, rv)        {            rv[1] = {};            for (var name in template[1]) {                if (attrs.hasOwnProperty(name)) {                    var new_name = do_substitution(name).join("");                    var new_value = do_substitution(attrs[name]).join("");                    rv[1][new_name] = new_value;                }            }        }        function substitute_children(children, rv)        {            for (var i = 0; i < children.length; i++) {                if (children[i] instanceof Object) {                    var replacement = substitute(children[i], substitutions);                    if (replacement !== null) {                        if (is_single_node(replacement)) {                            rv.push(replacement);                        } else {                            extend(rv, replacement);                        }                    }                } else {                    extend(rv, do_substitution(String(children[i])));                }            }            return rv;        }        var rv = [];        rv.push(do_substitution(String(template[0])).join(""));        if (template[0] === "{text}") {            substitute_children(template.slice(1), rv);        } else {            substitute_attrs(template[1], rv);            substitute_children(template.slice(2), rv);        }        return rv;    }    function make_dom_single(template, doc)    {        var output_document = doc || document;        var element;        if (template[0] === "{text}") {            element = output_document.createTextNode("");            for (var i = 1; i < template.length; i++) {                element.data += template[i];            }        } else {            element = output_document.createElementNS(xhtml_ns, template[0]);            for (var name in template[1]) {                if (template[1].hasOwnProperty(name)) {                    element.setAttribute(name, template[1][name]);                }            }            for (var i = 2; i < template.length; i++) {                if (template[i] instanceof Object) {                    var sub_element = make_dom(template[i]);                    element.appendChild(sub_element);                } else {                    var text_node = output_document.createTextNode(template[i]);                    element.appendChild(text_node);                }            }        }        return element;    }    function make_dom(template, substitutions, output_document)    {        if (is_single_node(template)) {            return make_dom_single(template, output_document);        }        return map(template, function(x) {                       return make_dom_single(x, output_document);                   });    }    function render(template, substitutions, output_document)    {        return make_dom(substitute(template, substitutions), output_document);    }    /*     * Utility functions     */    function assert(expected_true, function_name, description, error, substitutions)    {        if (expected_true !== true) {            var msg = make_message(function_name, description,                                   error, substitutions);            throw new AssertionError(msg);        }    }    /**     * @class     * Exception type that represents a failing assert.     *     * @param {string} message - Error message.     */    function AssertionError(message)    {        if (typeof message == "string") {            message = sanitize_unpaired_surrogates(message);        }        this.message = message;        this.stack = get_stack();    }    expose(AssertionError, "AssertionError");    AssertionError.prototype = Object.create(Error.prototype);    const get_stack = function() {        var stack = new Error().stack;        // 'Error.stack' is not supported in all browsers/versions        if (!stack) {            return "(Stack trace unavailable)";        }        var lines = stack.split("\n");        // Create a pattern to match stack frames originating within testharness.js.  These include the        // script URL, followed by the line/col (e.g., '/resources/testharness.js:120:21').        // Escape the URL per http://stackoverflow.com/questions/3561493/is-there-a-regexp-escape-function-in-javascript        // in case it contains RegExp characters.        var script_url = get_script_url();        var re_text = script_url ? script_url.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&') : "\\btestharness.js";        var re = new RegExp(re_text + ":\\d+:\\d+");        // Some browsers include a preamble that specifies the type of the error object.  Skip this by        // advancing until we find the first stack frame originating from testharness.js.        var i = 0;        while (!re.test(lines[i]) && i < lines.length) {            i++;        }        // Then skip the top frames originating from testharness.js to begin the stack at the test code.        while (re.test(lines[i]) && i < lines.length) {            i++;        }        // Paranoid check that we didn't skip all frames.  If so, return the original stack unmodified.        if (i >= lines.length) {            return stack;        }        return lines.slice(i).join("\n");    }    function OptionalFeatureUnsupportedError(message)    {        AssertionError.call(this, message);    }    OptionalFeatureUnsupportedError.prototype = Object.create(AssertionError.prototype);    expose(OptionalFeatureUnsupportedError, "OptionalFeatureUnsupportedError");    function make_message(function_name, description, error, substitutions)    {        for (var p in substitutions) {            if (substitutions.hasOwnProperty(p)) {                substitutions[p] = format_value(substitutions[p]);            }        }        var node_form = substitute(["{text}", "${function_name}: ${description}" + error],                                   merge({function_name:function_name,                                          description:(description?description + " ":"")},                                          substitutions));        return node_form.slice(1).join("");    }    function filter(array, callable, thisObj) {        var rv = [];        for (var i = 0; i < array.length; i++) {            if (array.hasOwnProperty(i)) {                var pass = callable.call(thisObj, array[i], i, array);                if (pass) {                    rv.push(array[i]);                }            }        }        return rv;    }    function map(array, callable, thisObj)    {        var rv = [];        rv.length = array.length;        for (var i = 0; i < array.length; i++) {            if (array.hasOwnProperty(i)) {                rv[i] = callable.call(thisObj, array[i], i, array);            }        }        return rv;    }    function extend(array, items)    {        Array.prototype.push.apply(array, items);    }    function forEach(array, callback, thisObj)    {        for (var i = 0; i < array.length; i++) {            if (array.hasOwnProperty(i)) {                callback.call(thisObj, array[i], i, array);            }        }    }    /**     * Immediately invoke a "iteratee" function with a series of values in     * parallel and invoke a final "done" function when all of the "iteratee"     * invocations have signaled completion.     *     * If all callbacks complete synchronously (or if no callbacks are     * specified), the ``done_callback`` will be invoked synchronously. It is the     * responsibility of the caller to ensure asynchronicity in cases where     * that is desired.     *     * @param {array} value Zero or more values to use in the invocation of     *                      ``iter_callback``     * @param {function} iter_callback A function that will be invoked     *                                 once for each of the values min     *                                 ``value``. Two arguments will     *                                 be available in each     *                                 invocation: the value from     *                                 ``value`` and a function that     *                                 must be invoked to signal     *                                 completion     * @param {function} done_callback A function that will be invoked after     *                                 all operations initiated by the     *                                 ``iter_callback`` function have signaled     *                                 completion     */    function all_async(values, iter_callback, done_callback)    {        var remaining = values.length;        if (remaining === 0) {            done_callback();        }        forEach(values,                function(element) {                    var invoked = false;                    var elDone = function() {                        if (invoked) {                            return;                        }                        invoked = true;                        remaining -= 1;                        if (remaining === 0) {                            done_callback();                        }                    };                    iter_callback(element, elDone);                });    }    function merge(a,b)    {        var rv = {};        var p;        for (p in a) {            rv[p] = a[p];        }        for (p in b) {            rv[p] = b[p];        }        return rv;    }    function expose(object, name)    {        var components = name.split(".");        var target = global_scope;        for (var i = 0; i < components.length - 1; i++) {            if (!(components[i] in target)) {                target[components[i]] = {};            }            target = target[components[i]];        }        target[components[components.length - 1]] = object;    }    function is_same_origin(w) {        try {            'random_prop' in w;            return true;        } catch (e) {            return false;        }    }    /** Returns the 'src' URL of the first <script> tag in the page to include the file 'testharness.js'. */    function get_script_url()    {        if (!('document' in global_scope)) {            return undefined;        }        var scripts = document.getElementsByTagName("script");        for (var i = 0; i < scripts.length; i++) {            var src;            if (scripts[i].src) {                src = scripts[i].src;            } else if (scripts[i].href) {                //SVG case                src = scripts[i].href.baseVal;            }            var matches = src && src.match(/^(.*\/|)testharness\.js$/);            if (matches) {                return src;            }        }        return undefined;    }    /** Returns the <title> or filename or "Untitled" */    function get_title()    {        if ('document' in global_scope) {            //Don't use document.title to work around an Opera/Presto bug in XHTML documents            var title = document.getElementsByTagName("title")[0];            if (title && title.firstChild && title.firstChild.data) {                return title.firstChild.data;            }        }        if ('META_TITLE' in global_scope && META_TITLE) {            return META_TITLE;        }        if ('location' in global_scope) {            return location.pathname.substring(location.pathname.lastIndexOf('/') + 1, location.pathname.indexOf('.'));        }        return "Untitled";    }    /**     * Setup globals     */    var tests = new Tests();    if (global_scope.addEventListener) {        var error_handler = function(error, message, stack) {            var optional_unsupported = error instanceof OptionalFeatureUnsupportedError;            if (tests.file_is_test) {                var test = tests.tests[0];                if (test.phase >= test.phases.HAS_RESULT) {                    return;                }                var status = optional_unsupported ? test.PRECONDITION_FAILED : test.FAIL;                test.set_status(status, message, stack);                test.phase = test.phases.HAS_RESULT;            } else if (!tests.allow_uncaught_exception) {                var status = optional_unsupported ? tests.status.PRECONDITION_FAILED : tests.status.ERROR;                tests.status.status = status;                tests.status.message = message;                tests.status.stack = stack;            }            // Do not transition to the "complete" phase if the test has been            // configured to allow uncaught exceptions. This gives the test an            // opportunity to define subtests based on the exception reporting            // behavior.            if (!tests.allow_uncaught_exception) {                done();            }        };        addEventListener("error", function(e) {            var message = e.message;            var stack;            if (e.error && e.error.stack) {                stack = e.error.stack;            } else {                stack = e.filename + ":" + e.lineno + ":" + e.colno;            }            error_handler(e.error, message, stack);        }, false);        addEventListener("unhandledrejection", function(e) {            var message;            if (e.reason && e.reason.message) {                message = "Unhandled rejection: " + e.reason.message;            } else {                message = "Unhandled rejection";            }            var stack;            if (e.reason && e.reason.stack) {                stack = e.reason.stack;            }            error_handler(e.reason, message, stack);        }, false);    }    test_environment.on_tests_ready();    /**     * Stylesheet     */     var stylesheetContent = "\html {\    font-family:DejaVu Sans, Bitstream Vera Sans, Arial, Sans;\}\\#log .warning,\#log .warning a {\  color: black;\  background: yellow;\}\\#log .error,\#log .error a {\  color: white;\  background: red;\}\\section#summary {\    margin-bottom:1em;\}\\table#results {\    border-collapse:collapse;\    table-layout:fixed;\    width:100%;\}\\table#results > thead > tr > th:first-child,\table#results > tbody > tr > td:first-child {\    width:8em;\}\\table#results > thead > tr > th:last-child,\table#results > thead > tr > td:last-child {\    width:50%;\}\\table#results.assertions > thead > tr > th:last-child,\table#results.assertions > tbody > tr > td:last-child {\    width:35%;\}\\table#results > thead > > tr > th {\    padding:0;\    padding-bottom:0.5em;\    border-bottom:medium solid black;\}\\table#results > tbody > tr> td {\    padding:1em;\    padding-bottom:0.5em;\    border-bottom:thin solid black;\}\\.pass {\    color:green;\}\\.fail {\    color:red;\}\\tr.timeout {\    color:red;\}\\tr.notrun {\    color:blue;\}\\tr.optionalunsupported {\    color:blue;\}\\.ok {\    color:green;\}\\.error {\    color:red;\}\\.pass, .fail, .timeout, .notrun, .optionalunsupported .ok, .timeout, .error {\    font-variant:small-caps;\}\\table#results span {\    display:block;\}\\table#results span.expected {\    font-family:DejaVu Sans Mono, Bitstream Vera Sans Mono, Monospace;\    white-space:pre;\}\\table#results span.actual {\    font-family:DejaVu Sans Mono, Bitstream Vera Sans Mono, Monospace;\    white-space:pre;\}\";})(self);// vim: set expandtab shiftwidth=4 tabstop=4: