Add m-esr52 at 52.6.0

1 files changed, 2657 insertions, 0 deletions

diff --git a/dom/imptests/testharness.js b/dom/imptests/testharness.js
new file mode 100644
index 000000000..f4c66aae6
--- /dev/null
+++ b/dom/imptests/testharness.js
@@ -0,0 +1,2657 @@
+/*global self*/
+/*jshint latedef: nofunc*/
+/*
+Distributed under both the W3C Test Suite License [1] and the W3C
+3-clause BSD License [2]. To contribute to a W3C Test Suite, see the
+policies and contribution forms [3].
+
+[1] http://www.w3.org/Consortium/Legal/2008/04-testsuite-license
+[2] http://www.w3.org/Consortium/Legal/2008/03-bsd-license
+[3] http://www.w3.org/2004/10/27-testcases
+*/
+
+/* Documentation is in docs/api.md */
+
+(function ()
+{
+    var debug = false;
+    // 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"]
+    };
+
+    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();
+     *
+     *   // Should return the global scope object.
+     *   object global_scope();
+     * };
+     */
+
+    /*
+     * 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.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) {
+                             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()});
+                         }]
+        }
+
+        on_event(window, 'load', function() {
+            this_obj.all_loaded = true;
+        });
+    }
+
+    WindowTestEnvironment.prototype._dispatch = function(selector, callback_args, 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 (debug) {
+                                    throw e;
+                                }
+                            }
+                        }
+                    }
+                    if (supports_post_message(w) && w !== self) {
+                        w.postMessage(message_arg, "*");
+                    }
+                });
+    };
+
+    WindowTestEnvironment.prototype._forEach_windows = function(callback) {
+        // Iterate of the the windows [self ... top, opener]. The callback is passed
+        // two objects, the first one is the windows object itself, the second one
+        // is a boolean indicating whether or not its 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;
+            var origins = location.ancestorOrigins;
+            while (w != w.parent) {
+                w = w.parent;
+                // In WebKit, calls to parent windows' properties that aren't on the same
+                // origin cause an error message to be displayed in the error console but
+                // don't throw an exception. This is a deviation from the current HTML5
+                // spec. See: https://bugs.webkit.org/show_bug.cgi?id=43504
+                // The problem with WebKit's behavior is that it pollutes the error console
+                // with error messages that can't be caught.
+                //
+                // This issue can be mitigated by relying on the (for now) proprietary
+                // `location.ancestorOrigins` property which returns an ordered list of
+                // the origins of enclosing windows. See:
+                // http://trac.webkit.org/changeset/113945.
+                if (origins) {
+                    so = (location.origin == origins[i]);
+                } else {
+                    so = is_same_origin(w);
+                }
+                cache.push([w, so]);
+                i++;
+            }
+            w = window.opener;
+            if (w) {
+                // window.opener isn't included in the `location.ancestorOrigins` prop.
+                // We'll just have to deal with a simple check and an error msg on WebKit
+                // browsers in this case.
+                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) {
+            this_obj.output_handler.show_results(tests, harness_status);
+        });
+        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() {
+        //Don't use document.title to work around an Opera bug in XHTML documents
+        var title = document.getElementsByTagName("title")[0];
+        var prefix = (title && title.firstChild && title.firstChild.data) || "Untitled";
+        var suffix = this.name_counter > 0 ? " " + this.name_counter : "";
+        this.name_counter++;
+        return prefix + 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;
+    };
+
+    WindowTestEnvironment.prototype.global_scope = function() {
+        return window;
+    };
+
+    /*
+     * 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 "Untitled" + 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) {
+                    this_obj._dispatch({
+                        type: "complete",
+                        tests: map(tests,
+                            function(test) {
+                                return test.structured_clone();
+                            }),
+                        status: harness_status.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;
+    };
+
+    WorkerTestEnvironment.prototype.global_scope = function() {
+        return self;
+    };
+
+    /*
+     * 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);
+                });
+    }
+    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.type && event.data.type === "connect") {
+                        if (event.ports && event.ports[0]) {
+                            // If a MessageChannel was passed, then use it to
+                            // send results back to the main window.  This
+                            // allows the tests to work even if the browser
+                            // does not fully support MessageEvent.source in
+                            // ServiceWorkers yet.
+                            this_obj._add_message_port(event.ports[0]);
+                            event.ports[0].start();
+                        } else {
+                            // If there is no MessageChannel, then attempt to
+                            // use the MessageEvent.source to send results
+                            // back to the main window.
+                            this_obj._add_message_port(event.source);
+                        }
+                    }
+                });
+
+        // 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.
+        on_event(self, "install",
+                function(event) {
+                    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;
+        }
+    };
+
+    function create_test_environment() {
+        if ('document' in self) {
+            return new WindowTestEnvironment();
+        }
+        if ('DedicatedWorkerGlobalScope' in self &&
+            self instanceof DedicatedWorkerGlobalScope) {
+            return new DedicatedWorkerTestEnvironment();
+        }
+        if ('SharedWorkerGlobalScope' in self &&
+            self instanceof SharedWorkerGlobalScope) {
+            return new SharedWorkerTestEnvironment();
+        }
+        if ('ServiceWorkerGlobalScope' in self &&
+            self instanceof ServiceWorkerGlobalScope) {
+            return new ServiceWorkerTestEnvironment();
+        }
+        throw new Error("Unsupported test environment");
+    }
+
+    var test_environment = create_test_environment();
+
+    function is_shared_worker(worker) {
+        return 'SharedWorker' in self && worker instanceof SharedWorker;
+    }
+
+    function is_service_worker(worker) {
+        return 'ServiceWorker' in self && worker instanceof ServiceWorker;
+    }
+
+    /*
+     * API functions
+     */
+
+    function test(func, name, properties)
+    {
+        var test_name = name ? name : test_environment.next_default_test_name();
+        properties = properties ? properties : {};
+        var test_obj = new Test(test_name, properties);
+        test_obj.step(func, test_obj, test_obj);
+        if (test_obj.phase === test_obj.phases.STARTED) {
+            test_obj.done();
+        }
+    }
+
+    function async_test(func, name, properties)
+    {
+        if (typeof func !== "function") {
+            properties = name;
+            name = func;
+            func = null;
+        }
+        var test_name = name ? name : test_environment.next_default_test_name();
+        properties = properties ? properties : {};
+        var test_obj = new Test(test_name, properties);
+        if (func) {
+            test_obj.step(func, test_obj, test_obj);
+        }
+        return test_obj;
+    }
+
+    function promise_test(func, name, properties) {
+        var test = async_test(name, properties);
+        // If there is no promise tests queue make one.
+        test.step(function() {
+            if (!tests.promise_tests) {
+                tests.promise_tests = Promise.resolve();
+            }
+        });
+        tests.promise_tests = tests.promise_tests.then(function() {
+            return Promise.resolve(test.step(func, test, test))
+                .then(
+                    function() {
+                        test.done();
+                    })
+                .catch(test.step_func(
+                    function(value) {
+                        if (value instanceof AssertionError) {
+                            throw value;
+                        }
+                        assert(false, "promise_test", null,
+                               "Unhandled rejection with value: ${value}", {value:value});
+                    }));
+        });
+    }
+
+    function promise_rejects(test, expected, promise) {
+        return promise.then(test.unreached_func("Should have rejected.")).catch(function(e) {
+            assert_throws(expected, function() { throw e });
+        });
+    }
+
+    /**
+     * This constructor helper allows DOM events to be handled using Promises,
+     * which 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.
+     */
+    function EventWatcher(test, watchedNode, eventTypes)
+    {
+        if (typeof eventTypes == 'string') {
+            eventTypes = [eventTypes];
+        }
+
+        var waitingFor = 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 (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;
+            resolveFunc(evt);
+        });
+
+        for (var i = 0; i < eventTypes.length; i++) {
+            watchedNode.addEventListener(eventTypes[i], eventHandler);
+        }
+
+        /**
+         * Returns a Promise that will resolve after the specified event or
+         * series of events has occured.
+         */
+        this.wait_for = function(types) {
+            if (waitingFor) {
+                return Promise.reject('Already waiting for an event or events');
+            }
+            if (typeof types == 'string') {
+                types = [types];
+            }
+            return new Promise(function(resolve, reject) {
+                waitingFor = {
+                    types: types,
+                    resolve: resolve,
+                    reject: reject
+                };
+            });
+        };
+
+        function stop_watching() {
+            for (var i = 0; i < eventTypes.length; i++) {
+                watchedNode.removeEventListener(eventTypes[i], eventHandler);
+            }
+        };
+
+        test.add_cleanup(stop_watching);
+
+        return this;
+    }
+    expose(EventWatcher, 'EventWatcher');
+
+    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);
+    }
+
+    function done() {
+        if (tests.tests.length === 0) {
+            tests.set_file_is_test();
+        }
+        if (tests.file_is_test) {
+            tests.tests[0].done();
+        }
+        tests.end_wait();
+    }
+
+    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);
+                });
+    }
+
+    function on_event(object, event, callback)
+    {
+        object.addEventListener(event, callback, false);
+    }
+
+    function step_timeout(f, t) {
+        var outer_this = this;
+        var args = Array.prototype.slice.call(arguments, 2);
+        return setTimeout(function() {
+            f.apply(outer_this, args);
+        }, t * tests.timeout_multiplier);
+    }
+
+    expose(test, 'test');
+    expose(async_test, 'async_test');
+    expose(promise_test, 'promise_test');
+    expose(promise_rejects, 'promise_rejects');
+    expose(generate_tests, 'generate_tests');
+    expose(setup, '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
+        if ("nodeType" in object &&
+            "nodeName" in object &&
+            "nodeValue" in object &&
+            "childNodes" in object) {
+            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;
+    }
+
+    /*
+     * Convert a value to a nice, human-readable string
+     */
+    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)) {
+            return "[" + val.map(function(x) {return format_value(x, seen);}).join(", ") + "]";
+        }
+
+        switch (typeof val) {
+        case "string":
+            val = val.replace("\\", "\\\\");
+            for (var i = 0; i < 32; i++) {
+                var replace = "\\";
+                switch (i) {
+                case 0: replace += "0"; break;
+                case 1: replace += "x01"; break;
+                case 2: replace += "x02"; break;
+                case 3: replace += "x03"; break;
+                case 4: replace += "x04"; break;
+                case 5: replace += "x05"; break;
+                case 6: replace += "x06"; break;
+                case 7: replace += "x07"; break;
+                case 8: replace += "b"; break;
+                case 9: replace += "t"; break;
+                case 10: replace += "n"; break;
+                case 11: replace += "v"; break;
+                case 12: replace += "f"; break;
+                case 13: replace += "r"; break;
+                case 14: replace += "x0e"; break;
+                case 15: replace += "x0f"; break;
+                case 16: replace += "x10"; break;
+                case 17: replace += "x11"; break;
+                case 18: replace += "x12"; break;
+                case 19: replace += "x13"; break;
+                case 20: replace += "x14"; break;
+                case 21: replace += "x15"; break;
+                case 22: replace += "x16"; break;
+                case 23: replace += "x17"; break;
+                case 24: replace += "x18"; break;
+                case 25: replace += "x19"; break;
+                case 26: replace += "x1a"; break;
+                case 27: replace += "x1b"; break;
+                case 28: replace += "x1c"; break;
+                case 29: replace += "x1d"; break;
+                case 30: replace += "x1e"; break;
+                case 31: replace += "x1f"; break;
+                }
+                val = val.replace(RegExp(String.fromCharCode(i), "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:
+            return typeof val + ' "' + truncate(String(val), 60) + '"';
+        }
+    }
+    expose(format_value, "format_value");
+
+    /*
+     * Assertions
+     */
+
+    function assert_true(actual, description)
+    {
+        assert(actual === true, "assert_true", description,
+                                "expected true got ${actual}", {actual:actual});
+    }
+    expose(assert_true, "assert_true");
+
+    function assert_false(actual, description)
+    {
+        assert(actual === false, "assert_false", description,
+                                 "expected false got ${actual}", {actual:actual});
+    }
+    expose(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;
+    }
+
+    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_equals, "assert_equals");
+
+    function assert_not_equals(actual, expected, description)
+    {
+         /*
+          * Test if two primitives are unequal or two objects
+          * are different objects
+          */
+        assert(!same_value(actual, expected), "assert_not_equals", description,
+                                              "got disallowed value ${actual}",
+                                              {actual:actual});
+    }
+    expose(assert_not_equals, "assert_not_equals");
+
+    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_in_array, "assert_in_array");
+
+    function assert_object_equals(actual, expected, description)
+    {
+         //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, actual:actual});
+                 }
+             }
+             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_object_equals, "assert_object_equals");
+
+    function assert_array_equals(actual, expected, description)
+    {
+        assert(actual.length === expected.length,
+               "assert_array_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_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(same_value(expected[i], actual[i]),
+                   "assert_array_equals", description,
+                   "property ${i}, expected ${expected} but got ${actual}",
+                   {i:i, expected:expected[i], actual:actual[i]});
+        }
+    }
+    expose(assert_array_equals, "assert_array_equals");
+
+    function assert_approx_equals(actual, expected, epsilon, description)
+    {
+        /*
+         * Test if two primitive numbers are equal withing +/- epsilon
+         */
+        assert(typeof actual === "number",
+               "assert_approx_equals", description,
+               "expected a number but got a ${type_actual}",
+               {type_actual:typeof actual});
+
+        assert(Math.abs(actual - expected) <= epsilon,
+               "assert_approx_equals", description,
+               "expected ${expected} +/- ${epsilon} but got ${actual}",
+               {expected:expected, actual:actual, epsilon:epsilon});
+    }
+    expose(assert_approx_equals, "assert_approx_equals");
+
+    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_less_than, "assert_less_than");
+
+    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_greater_than, "assert_greater_than");
+
+    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_between_exclusive, "assert_between_exclusive");
+
+    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_less_than_equal, "assert_less_than_equal");
+
+    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_greater_than_equal, "assert_greater_than_equal");
+
+    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_between_inclusive, "assert_between_inclusive");
+
+    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_regexp_match, "assert_regexp_match");
+
+    function assert_class_string(object, class_string, description) {
+        assert_equals({}.toString.call(object), "[object " + class_string + "]",
+                      description);
+    }
+    expose(assert_class_string, "assert_class_string");
+
+
+    function _assert_own_property(name) {
+        return function(object, property_name, description)
+        {
+            assert(object.hasOwnProperty(property_name),
+                   name, description,
+                   "expected property ${p} missing", {p:property_name});
+        };
+    }
+    expose(_assert_own_property("assert_exists"), "assert_exists");
+    expose(_assert_own_property("assert_own_property"), "assert_own_property");
+
+    function assert_not_exists(object, property_name, description)
+    {
+        assert(!object.hasOwnProperty(property_name),
+               "assert_not_exists", description,
+               "unexpected property ${p} found", {p:property_name});
+    }
+    expose(assert_not_exists, "assert_not_exists");
+
+    function _assert_inherits(name) {
+        return function (object, property_name, description)
+        {
+            assert(typeof object === "object",
+                   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});
+        };
+    }
+    expose(_assert_inherits("assert_inherits"), "assert_inherits");
+    expose(_assert_inherits("assert_idl_attribute"), "assert_idl_attribute");
+
+    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 ${p} succeeded",
+                    {p:property_name});
+         } finally {
+             object[property_name] = initial_value;
+         }
+    }
+    expose(assert_readonly, "assert_readonly");
+
+    function assert_throws(code, func, description)
+    {
+        try {
+            func.call(this);
+            assert(false, "assert_throws", description,
+                   "${func} did not throw", {func:func});
+        } catch (e) {
+            if (e instanceof AssertionError) {
+                throw e;
+            }
+            if (code === null) {
+                return;
+            }
+            if (typeof code === "object") {
+                assert(typeof e == "object" && "name" in e && e.name == code.name,
+                       "assert_throws", description,
+                       "${func} threw ${actual} (${actual_name}) expected ${expected} (${expected_name})",
+                                    {func:func, actual:e, actual_name:e.name,
+                                     expected:code,
+                                     expected_name:code.name});
+                return;
+            }
+
+            var code_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',
+                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 in code_name_map ? code_name_map[code] : code;
+
+            var name_code_map = {
+                IndexSizeError: 1,
+                HierarchyRequestError: 3,
+                WrongDocumentError: 4,
+                InvalidCharacterError: 5,
+                NoModificationAllowedError: 7,
+                NotFoundError: 8,
+                NotSupportedError: 9,
+                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,
+            };
+
+            if (!(name in name_code_map)) {
+                throw new AssertionError('Test bug: unrecognized DOMException code "' + code + '" passed to assert_throws()');
+            }
+
+            var required_props = { code: name_code_map[name] };
+
+            if (required_props.code === 0 ||
+               (typeof e == "object" &&
+                "name" in e &&
+                e.name !== e.name.toUpperCase() &&
+                e.name !== "DOMException")) {
+                // New style exception: also test the name property.
+                required_props.name = name;
+            }
+
+            //We'd like to test that e instanceof the appropriate interface,
+            //but we can't, because we don't know what window it was created
+            //in.  It might be an instanceof the appropriate interface on some
+            //unknown other window.  TODO: Work around this somehow?
+
+            assert(typeof e == "object",
+                   "assert_throws", description,
+                   "${func} threw ${e} with type ${type}, not an object",
+                   {func:func, e:e, type:typeof e});
+
+            for (var prop in required_props) {
+                assert(typeof e == "object" && prop in e && e[prop] == required_props[prop],
+                       "assert_throws", description,
+                       "${func} threw ${e} that is not a DOMException " + code + ": property ${prop} is equal to ${actual}, expected ${expected}",
+                       {func:func, e:e, prop:prop, actual:e[prop], expected:required_props[prop]});
+            }
+        }
+    }
+    expose(assert_throws, "assert_throws");
+
+    function assert_unreached(description) {
+         assert(false, "assert_unreached", description,
+                "Reached unreachable code");
+    }
+    expose(assert_unreached, "assert_unreached");
+
+    function assert_any(assert_func, actual, expected_array)
+    {
+        var args = [].slice.call(arguments, 3);
+        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"));
+        }
+    }
+    expose(assert_any, "assert_any");
+
+    function Test(name, properties)
+    {
+        if (tests.file_is_test && tests.tests.length) {
+            throw new Error("Tried to create a test with file_is_test");
+        }
+        this.name = name;
+
+        this.phase = this.phases.INITIAL;
+
+        this.status = this.NOTRUN;
+        this.timeout_id = null;
+        this.index = null;
+
+        this.properties = properties;
+        var timeout = properties.timeout ? properties.timeout : settings.test_timeout;
+        if (timeout !== null) {
+            this.timeout_length = timeout * tests.timeout_multiplier;
+        } else {
+            this.timeout_length = null;
+        }
+
+        this.message = null;
+        this.stack = null;
+
+        this.steps = [];
+
+        this.cleanup_callbacks = [];
+
+        tests.push(this);
+    }
+
+    Test.statuses = {
+        PASS:0,
+        FAIL:1,
+        TIMEOUT:2,
+        NOTRUN:3
+    };
+
+    Test.prototype = merge({}, Test.statuses);
+
+    Test.prototype.phases = {
+        INITIAL:0,
+        STARTED:1,
+        HAS_RESULT:2,
+        COMPLETE:3
+    };
+
+    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),
+            }, 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;
+        return this._structured_clone;
+    };
+
+    Test.prototype.step = function(func, this_obj)
+    {
+        if (this.phase > this.phases.STARTED) {
+            return;
+        }
+        this.phase = this.phases.STARTED;
+        //If we don't get a result before the harness times out that will be a test timout
+        this.set_status(this.TIMEOUT, "Test timed out");
+
+        tests.started = true;
+        tests.notify_test_state(this);
+
+        if (this.timeout_id === null) {
+            this.set_timeout();
+        }
+
+        this.steps.push(func);
+
+        if (arguments.length === 1) {
+            this_obj = this;
+        }
+
+        try {
+            return func.apply(this_obj, Array.prototype.slice.call(arguments, 2));
+        } catch (e) {
+            if (this.phase >= this.phases.HAS_RESULT) {
+                return;
+            }
+            var message = String((typeof e === "object" && e !== null) ? e.message : e);
+            var stack = e.stack ? e.stack : null;
+
+            this.set_status(this.FAIL, message, stack);
+            this.phase = this.phases.HAS_RESULT;
+            this.done();
+        }
+    };
+
+    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)));
+        };
+    };
+
+    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();
+        };
+    };
+
+    Test.prototype.unreached_func = function(description)
+    {
+        return this.step_func(function() {
+            assert_unreached(description);
+        });
+    };
+
+    Test.prototype.step_timeout = function(f, timeout) {
+        var test_this = this;
+        var args = Array.prototype.slice.call(arguments, 2);
+        return setTimeout(this.step_func(function() {
+            return f.apply(test_this, args);
+        }, timeout * tests.timeout_multiplier));
+    }
+
+    Test.prototype.add_cleanup = function(callback) {
+        this.cleanup_callbacks.push(callback);
+    };
+
+    Test.prototype.force_timeout = function() {
+        this.set_status(this.TIMEOUT);
+        this.phase = this.phases.HAS_RESULT;
+    };
+
+    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;
+    };
+
+    Test.prototype.timeout = function()
+    {
+        this.timeout_id = null;
+        this.set_status(this.TIMEOUT, "Test timed out");
+        this.phase = this.phases.HAS_RESULT;
+        this.done();
+    };
+
+    Test.prototype.done = function()
+    {
+        if (this.phase == this.phases.COMPLETE) {
+            return;
+        }
+
+        if (this.phase <= this.phases.STARTED) {
+            this.set_status(this.PASS, null);
+        }
+
+        this.phase = this.phases.COMPLETE;
+
+        clearTimeout(this.timeout_id);
+        tests.result(this);
+        this.cleanup();
+    };
+
+    Test.prototype.cleanup = function() {
+        forEach(this.cleanup_callbacks,
+                function(cleanup_callback) {
+                    cleanup_callback();
+                });
+    };
+
+    /*
+     * 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);
+        tests.push(this);
+    }
+
+    RemoteTest.prototype.structured_clone = function() {
+        var clone = {};
+        Object.keys(this).forEach(
+                (function(key) {
+                    if (typeof(this[key]) === "object") {
+                        clone[key] = merge({}, this[key]);
+                    } else {
+                        clone[key] = this[key];
+                    }
+                }).bind(this));
+        clone.phases = merge({}, this.phases);
+        return clone;
+    };
+
+    RemoteTest.prototype.cleanup = function() {};
+    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;
+    }
+
+    /*
+     * A RemoteWorker listens for test events from a worker. These events are
+     * then used to construct and maintain RemoteTest objects that mirror the
+     * tests running on the remote worker.
+     */
+    function RemoteWorker(worker) {
+        this.running = true;
+        this.tests = new Array();
+
+        var this_obj = this;
+        worker.onerror = function(error) { this_obj.worker_error(error); };
+
+        var message_port;
+
+        if (is_service_worker(worker)) {
+            if (window.MessageChannel) {
+                // The ServiceWorker's implicit MessagePort is currently not
+                // reliably accessible from the ServiceWorkerGlobalScope due to
+                // Blink setting MessageEvent.source to null for messages sent
+                // via ServiceWorker.postMessage(). Until that's resolved,
+                // create an explicit MessageChannel and pass one end to the
+                // worker.
+                var message_channel = new MessageChannel();
+                message_port = message_channel.port1;
+                message_port.start();
+                worker.postMessage({type: "connect"}, [message_channel.port2]);
+            } else {
+                // If MessageChannel is not available, then try the
+                // ServiceWorker.postMessage() approach using MessageEvent.source
+                // on the other end.
+                message_port = navigator.serviceWorker;
+                worker.postMessage({type: "connect"});
+            }
+        } else if (is_shared_worker(worker)) {
+            message_port = worker.port;
+        } else {
+            message_port = worker;
+        }
+
+        // Keeping a reference to the worker until worker_done() is seen
+        // prevents the Worker object and its MessageChannel from going away
+        // before all the messages are dispatched.
+        this.worker = worker;
+
+        message_port.onmessage =
+            function(message) {
+                if (this_obj.running && (message.data.type in this_obj.message_handlers)) {
+                    this_obj.message_handlers[message.data.type].call(this_obj, message.data);
+                }
+            };
+    }
+
+    RemoteWorker.prototype.worker_error = function(error) {
+        var message = error.message || String(error);
+        var filename = (error.filename ? " " + error.filename: "");
+        // FIXME: Display worker error states separately from main document
+        // error state.
+        this.worker_done({
+            status: {
+                status: tests.status.ERROR,
+                message: "Error in worker" + filename + ": " + message,
+                stack: error.stack
+            }
+        });
+        error.preventDefault();
+    };
+
+    RemoteWorker.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);
+    };
+
+    RemoteWorker.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);
+    };
+
+    RemoteWorker.prototype.worker_done = function(data) {
+        if (tests.status.status === null &&
+            data.status.status !== data.status.OK) {
+            tests.status.status = data.status.status;
+            tests.status.message = data.status.message;
+            tests.status.stack = data.status.stack;
+        }
+        this.running = false;
+        this.worker = null;
+        if (tests.all_done()) {
+            tests.complete();
+        }
+    };
+
+    RemoteWorker.prototype.message_handlers = {
+        test_state: RemoteWorker.prototype.test_state,
+        result: RemoteWorker.prototype.test_done,
+        complete: RemoteWorker.prototype.worker_done
+    };
+
+    /*
+     * Harness
+     */
+
+    function TestsStatus()
+    {
+        this.status = null;
+        this.message = null;
+        this.stack = null;
+    }
+
+    TestsStatus.statuses = {
+        OK:0,
+        ERROR:1,
+        TIMEOUT:2
+    };
+
+    TestsStatus.prototype = merge({}, TestsStatus.statuses);
+
+    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;
+    };
+
+    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.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.pending_workers = [];
+
+        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 == "timeout_multiplier") {
+                    this.timeout_multiplier = value;
+                }
+            }
+        }
+
+        if (func) {
+            try {
+                func();
+            } catch (e) {
+                this.status.status = this.status.ERROR;
+                this.status.message = String(e);
+                this.status.stack = e.stack ? e.stack : null;
+            }
+        }
+        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
+        async_test();
+    };
+
+    Tests.prototype.set_timeout = function() {
+        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() {
+        if (this.status.status === null) {
+            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 && test_environment.all_loaded &&
+                this.num_pending === 0 && !this.wait_for_finish &&
+                !this.processing_callbacks &&
+                !this.pending_workers.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 (this.phase > this.phases.HAVE_RESULTS) {
+            return;
+        }
+        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;
+        }
+        this.phase = this.phases.COMPLETE;
+        var this_obj = this;
+        this.tests.forEach(
+            function(x)
+            {
+                if (x.phase < x.phases.COMPLETE) {
+                    this_obj.notify_result(x);
+                    x.cleanup();
+                    x.phase = x.phases.COMPLETE;
+                }
+            }
+        );
+        this.notify_complete();
+    };
+
+    Tests.prototype.notify_complete = function() {
+        var this_obj = this;
+        if (this.status.status === null) {
+            this.status.status = this.status.OK;
+        }
+
+        forEach (this.all_done_callbacks,
+                 function(callback)
+                 {
+                     callback(this_obj.tests, this_obj.status);
+                 });
+    };
+
+    Tests.prototype.fetch_tests_from_worker = function(worker) {
+        if (this.phase >= this.phases.COMPLETE) {
+            return;
+        }
+
+        this.pending_workers.push(new RemoteWorker(worker));
+    };
+
+    function fetch_tests_from_worker(port) {
+        tests.fetch_tests_from_worker(port);
+    }
+    expose(fetch_tests_from_worker, 'fetch_tests_from_worker');
+
+    function timeout() {
+        if (tests.timeout_length === null) {
+            tests.timeout();
+        }
+    }
+    expose(timeout, 'timeout');
+
+    function add_start_callback(callback) {
+        tests.start_callbacks.push(callback);
+    }
+
+    function add_test_state_callback(callback) {
+        tests.test_state_callbacks.push(callback);
+    }
+
+    function add_result_callback(callback) {
+        tests.test_done_callbacks.push(callback);
+    }
+
+    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 (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 (!document.body || document.readyState == "loading") {
+                return;
+            }
+            node = output_document.createElement("div");
+            node.id = "log";
+            output_document.body.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) {
+            return;
+        }
+        if (this.phase < this.HAVE_RESULTS) {
+            this.resolve_log();
+            this.phase = this.HAVE_RESULTS;
+        }
+        var done_count = tests.tests.length - tests.num_pending;
+        if (this.output_node) {
+            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) {
+        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 harness_url = get_harness_url();
+        if (harness_url !== null) {
+            var stylesheet = output_document.createElementNS(xhtml_ns, "link");
+            stylesheet.setAttribute("rel", "stylesheet");
+            stylesheet.setAttribute("href", harness_url + "testharness.css");
+            var heads = output_document.getElementsByTagName("head");
+            if (heads.length) {
+                heads[0].appendChild(stylesheet);
+            }
+        }
+
+        var status_text_harness = {};
+        status_text_harness[harness_status.OK] = "OK";
+        status_text_harness[harness_status.ERROR] = "Error";
+        status_text_harness[harness_status.TIMEOUT] = "Timeout";
+
+        var status_text = {};
+        status_text[Test.prototype.PASS] = "Pass";
+        status_text[Test.prototype.FAIL] = "Fail";
+        status_text[Test.prototype.TIMEOUT] = "Timeout";
+        status_text[Test.prototype.NOTRUN] = "Not Run";
+
+        var status_number = {};
+        forEach(tests,
+                function(test) {
+                    var status = status_text[test.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 = status_text_harness[harness_status.status];
+                                    var rv = [["section", {},
+                                               ["p", {},
+                                                "Harness status: ",
+                                                ["span", {"class":status_class(status)},
+                                                 status
+                                                ],
+                                               ]
+                                              ]];
+
+                                    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 (status_text.hasOwnProperty(i)) {
+                                        if (status_number.hasOwnProperty(status_text[i])) {
+                                            var status = status_text[i];
+                                            rv[0].push(["div", {"class":status_class(status)},
+                                                        ["label", {},
+                                                         ["input", {type:"checkbox", checked:"checked"}],
+                                                         status_number[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.parentNode.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."+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 '';
+        }
+
+        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++) {
+            html += '<tr class="' +
+                escape_html(status_class(status_text[tests[i].status])) +
+                '"><td>' +
+                escape_html(status_text[tests[i].status]) +
+                "</td><td>" +
+                escape_html(tests[i].name) +
+                "</td><td>" +
+                (assertions ? escape_html(get_assertion(tests[i])) + "</td><td>" : "") +
+                escape_html(tests[i].message ? tests[i].message : " ") +
+                (tests[i].stack ? "<pre>" +
+                 escape_html(tests[i].stack) +
+                 "</pre>": "") +
+                "</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 funcions
+     */
+    function assert(expected_true, function_name, description, error, substitutions)
+    {
+        if (tests.tests.length === 0) {
+            tests.set_file_is_test();
+        }
+        if (expected_true !== true) {
+            var msg = make_message(function_name, description,
+                                   error, substitutions);
+            throw new AssertionError(msg);
+        }
+    }
+
+    function AssertionError(message)
+    {
+        this.message = message;
+        this.stack = this.get_stack();
+    }
+
+    AssertionError.prototype = Object.create(Error.prototype);
+
+    AssertionError.prototype.get_stack = function() {
+        var stack = new Error().stack;
+        // IE11 does not initialize 'Error.stack' until the object is thrown.
+        if (!stack) {
+            try {
+                throw new Error();
+            } catch (e) {
+                stack = e.stack;
+            }
+        }
+
+        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').
+        var re = new RegExp((get_script_url() || "\\btestharness.js") + ":\\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 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);
+            }
+        }
+    }
+
+    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 = test_environment.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 self)) {
+            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 URL path at which the files for testharness.js are assumed to reside (e.g., '/resources/').
+        The path is derived from inspecting the 'src' of the <script> tag that included 'testharness.js'. */
+    function get_harness_url()
+    {
+        var script_url = get_script_url();
+
+        // Exclude the 'testharness.js' file from the returned path, but '+ 1' to include the trailing slash.
+        return script_url ? script_url.slice(0, script_url.lastIndexOf('/') + 1) : undefined;
+    }
+
+    function supports_post_message(w)
+    {
+        var supports;
+        var type;
+        // Given IE implements postMessage across nested iframes but not across
+        // windows or tabs, you can't infer cross-origin communication from the presence
+        // of postMessage on the current window object only.
+        //
+        // Touching the postMessage prop on a window can throw if the window is
+        // not from the same origin AND post message is not supported in that
+        // browser. So just doing an existence test here won't do, you also need
+        // to wrap it in a try..cacth block.
+        try {
+            type = typeof w.postMessage;
+            if (type === "function") {
+                supports = true;
+            }
+
+            // IE8 supports postMessage, but implements it as a host object which
+            // returns "object" as its `typeof`.
+            else if (type === "object") {
+                supports = true;
+            }
+
+            // This is the case where postMessage isn't supported AND accessing a
+            // window property across origins does NOT throw (e.g. old Safari browser).
+            else {
+                supports = false;
+            }
+        } catch (e) {
+            // This is the case where postMessage isn't supported AND accessing a
+            // window property across origins throws (e.g. old Firefox browser).
+            supports = false;
+        }
+        return supports;
+    }
+
+    /**
+     * Setup globals
+     */
+
+    var tests = new Tests();
+
+    addEventListener("error", function(e) {
+        if (tests.file_is_test) {
+            var test = tests.tests[0];
+            if (test.phase >= test.phases.HAS_RESULT) {
+                return;
+            }
+            test.set_status(test.FAIL, e.message, e.stack);
+            test.phase = test.phases.HAS_RESULT;
+            test.done();
+            done();
+        } else if (!tests.allow_uncaught_exception) {
+            tests.status.status = tests.status.ERROR;
+            tests.status.message = e.message;
+            tests.status.stack = e.stack;
+        }
+    });
+
+    test_environment.on_tests_ready();
+
+})();
+// vim: set expandtab shiftwidth=4 tabstop=4: