Add m-esr52 at 52.6.0

17 files changed, 2103 insertions, 0 deletions

diff --git a/testing/web-platform/harness/wptrunner/executors/__init__.py b/testing/web-platform/harness/wptrunner/executors/__init__.py
new file mode 100644
index 000000000..11e0c4cd7
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/__init__.py
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from base import (executor_kwargs,
+                  testharness_result_converter,
+                  reftest_result_converter,
+                  TestExecutor)
diff --git a/testing/web-platform/harness/wptrunner/executors/base.py b/testing/web-platform/harness/wptrunner/executors/base.py
new file mode 100644
index 000000000..f0ce16658
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/base.py
@@ -0,0 +1,329 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import hashlib
+import json
+import os
+import traceback
+import urlparse
+from abc import ABCMeta, abstractmethod
+
+from ..testrunner import Stop
+
+here = os.path.split(__file__)[0]
+
+
+def executor_kwargs(test_type, server_config, cache_manager, **kwargs):
+    timeout_multiplier = kwargs["timeout_multiplier"]
+    if timeout_multiplier is None:
+        timeout_multiplier = 1
+
+    executor_kwargs = {"server_config": server_config,
+                       "timeout_multiplier": timeout_multiplier,
+                       "debug_info": kwargs["debug_info"]}
+
+    if test_type == "reftest":
+        executor_kwargs["screenshot_cache"] = cache_manager.dict()
+
+    return executor_kwargs
+
+
+def strip_server(url):
+    """Remove the scheme and netloc from a url, leaving only the path and any query
+    or fragment.
+
+    url - the url to strip
+
+    e.g. http://example.org:8000/tests?id=1#2 becomes /tests?id=1#2"""
+
+    url_parts = list(urlparse.urlsplit(url))
+    url_parts[0] = ""
+    url_parts[1] = ""
+    return urlparse.urlunsplit(url_parts)
+
+
+class TestharnessResultConverter(object):
+    harness_codes = {0: "OK",
+                     1: "ERROR",
+                     2: "TIMEOUT"}
+
+    test_codes = {0: "PASS",
+                  1: "FAIL",
+                  2: "TIMEOUT",
+                  3: "NOTRUN"}
+
+    def __call__(self, test, result):
+        """Convert a JSON result into a (TestResult, [SubtestResult]) tuple"""
+        result_url, status, message, stack, subtest_results = result
+        assert result_url == test.url, ("Got results from %s, expected %s" %
+                                      (result_url, test.url))
+        harness_result = test.result_cls(self.harness_codes[status], message)
+        return (harness_result,
+                [test.subtest_result_cls(name, self.test_codes[status], message, stack)
+                 for name, status, message, stack in subtest_results])
+
+
+testharness_result_converter = TestharnessResultConverter()
+
+
+def reftest_result_converter(self, test, result):
+    return (test.result_cls(result["status"], result["message"],
+                            extra=result.get("extra")), [])
+
+
+def pytest_result_converter(self, test, data):
+    harness_data, subtest_data = data
+
+    if subtest_data is None:
+        subtest_data = []
+
+    harness_result = test.result_cls(*harness_data)
+    subtest_results = [test.subtest_result_cls(*item) for item in subtest_data]
+
+    return (harness_result, subtest_results)
+
+
+class ExecutorException(Exception):
+    def __init__(self, status, message):
+        self.status = status
+        self.message = message
+
+
+class TestExecutor(object):
+    __metaclass__ = ABCMeta
+
+    test_type = None
+    convert_result = None
+
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 debug_info=None):
+        """Abstract Base class for object that actually executes the tests in a
+        specific browser. Typically there will be a different TestExecutor
+        subclass for each test type and method of executing tests.
+
+        :param browser: ExecutorBrowser instance providing properties of the
+                        browser that will be tested.
+        :param server_config: Dictionary of wptserve server configuration of the
+                              form stored in TestEnvironment.external_config
+        :param timeout_multiplier: Multiplier relative to base timeout to use
+                                   when setting test timeout.
+        """
+        self.runner = None
+        self.browser = browser
+        self.server_config = server_config
+        self.timeout_multiplier = timeout_multiplier
+        self.debug_info = debug_info
+        self.last_environment = {"protocol": "http",
+                                 "prefs": {}}
+        self.protocol = None # This must be set in subclasses
+
+    @property
+    def logger(self):
+        """StructuredLogger for this executor"""
+        if self.runner is not None:
+            return self.runner.logger
+
+    def setup(self, runner):
+        """Run steps needed before tests can be started e.g. connecting to
+        browser instance
+
+        :param runner: TestRunner instance that is going to run the tests"""
+        self.runner = runner
+        if self.protocol is not None:
+            self.protocol.setup(runner)
+
+    def teardown(self):
+        """Run cleanup steps after tests have finished"""
+        if self.protocol is not None:
+            self.protocol.teardown()
+
+    def run_test(self, test):
+        """Run a particular test.
+
+        :param test: The test to run"""
+        if test.environment != self.last_environment:
+            self.on_environment_change(test.environment)
+
+        try:
+            result = self.do_test(test)
+        except Exception as e:
+            result = self.result_from_exception(test, e)
+
+        if result is Stop:
+            return result
+
+        # log result of parent test
+        if result[0].status == "ERROR":
+            self.logger.debug(result[0].message)
+
+        self.last_environment = test.environment
+
+        self.runner.send_message("test_ended", test, result)
+
+    def server_url(self, protocol):
+        return "%s://%s:%s" % (protocol,
+                               self.server_config["host"],
+                               self.server_config["ports"][protocol][0])
+
+    def test_url(self, test):
+        return urlparse.urljoin(self.server_url(test.environment["protocol"]), test.url)
+
+    @abstractmethod
+    def do_test(self, test):
+        """Test-type and protocol specific implementation of running a
+        specific test.
+
+        :param test: The test to run."""
+        pass
+
+    def on_environment_change(self, new_environment):
+        pass
+
+    def result_from_exception(self, test, e):
+        if hasattr(e, "status") and e.status in test.result_cls.statuses:
+            status = e.status
+        else:
+            status = "ERROR"
+        message = unicode(getattr(e, "message", ""))
+        if message:
+            message += "\n"
+        message += traceback.format_exc(e)
+        return test.result_cls(status, message), []
+
+
+class TestharnessExecutor(TestExecutor):
+    convert_result = testharness_result_converter
+
+
+class RefTestExecutor(TestExecutor):
+    convert_result = reftest_result_converter
+
+    def __init__(self, browser, server_config, timeout_multiplier=1, screenshot_cache=None,
+                 debug_info=None):
+        TestExecutor.__init__(self, browser, server_config,
+                              timeout_multiplier=timeout_multiplier,
+                              debug_info=debug_info)
+
+        self.screenshot_cache = screenshot_cache
+
+
+class RefTestImplementation(object):
+    def __init__(self, executor):
+        self.timeout_multiplier = executor.timeout_multiplier
+        self.executor = executor
+        # Cache of url:(screenshot hash, screenshot). Typically the
+        # screenshot is None, but we set this value if a test fails
+        # and the screenshot was taken from the cache so that we may
+        # retrieve the screenshot from the cache directly in the future
+        self.screenshot_cache = self.executor.screenshot_cache
+        self.message = None
+
+    @property
+    def logger(self):
+        return self.executor.logger
+
+    def get_hash(self, test, viewport_size, dpi):
+        timeout = test.timeout * self.timeout_multiplier
+        key = (test.url, viewport_size, dpi)
+
+        if key not in self.screenshot_cache:
+            success, data = self.executor.screenshot(test, viewport_size, dpi)
+
+            if not success:
+                return False, data
+
+            screenshot = data
+            hash_value = hashlib.sha1(screenshot).hexdigest()
+
+            self.screenshot_cache[key] = (hash_value, None)
+
+            rv = (hash_value, screenshot)
+        else:
+            rv = self.screenshot_cache[key]
+
+        self.message.append("%s %s" % (test.url, rv[0]))
+        return True, rv
+
+    def is_pass(self, lhs_hash, rhs_hash, relation):
+        assert relation in ("==", "!=")
+        self.message.append("Testing %s %s %s" % (lhs_hash, relation, rhs_hash))
+        return ((relation == "==" and lhs_hash == rhs_hash) or
+                (relation == "!=" and lhs_hash != rhs_hash))
+
+    def run_test(self, test):
+        viewport_size = test.viewport_size
+        dpi = test.dpi
+        self.message = []
+
+        # Depth-first search of reference tree, with the goal
+        # of reachings a leaf node with only pass results
+
+        stack = list(((test, item[0]), item[1]) for item in reversed(test.references))
+        while stack:
+            hashes = [None, None]
+            screenshots = [None, None]
+
+            nodes, relation = stack.pop()
+
+            for i, node in enumerate(nodes):
+                success, data = self.get_hash(node, viewport_size, dpi)
+                if success is False:
+                    return {"status": data[0], "message": data[1]}
+
+                hashes[i], screenshots[i] = data
+
+            if self.is_pass(hashes[0], hashes[1], relation):
+                if nodes[1].references:
+                    stack.extend(list(((nodes[1], item[0]), item[1]) for item in reversed(nodes[1].references)))
+                else:
+                    # We passed
+                    return {"status":"PASS", "message": None}
+
+        # We failed, so construct a failure message
+
+        for i, (node, screenshot) in enumerate(zip(nodes, screenshots)):
+            if screenshot is None:
+                success, screenshot = self.retake_screenshot(node, viewport_size, dpi)
+                if success:
+                    screenshots[i] = screenshot
+
+        log_data = [{"url": nodes[0].url, "screenshot": screenshots[0]}, relation,
+                    {"url": nodes[1].url, "screenshot": screenshots[1]}]
+
+        return {"status": "FAIL",
+                "message": "\n".join(self.message),
+                "extra": {"reftest_screenshots": log_data}}
+
+    def retake_screenshot(self, node, viewport_size, dpi):
+        success, data = self.executor.screenshot(node, viewport_size, dpi)
+        if not success:
+            return False, data
+
+        key = (node.url, viewport_size, dpi)
+        hash_val, _ = self.screenshot_cache[key]
+        self.screenshot_cache[key] = hash_val, data
+        return True, data
+
+
+class WdspecExecutor(TestExecutor):
+    convert_result = pytest_result_converter
+
+
+class Protocol(object):
+    def __init__(self, executor, browser):
+        self.executor = executor
+        self.browser = browser
+
+    @property
+    def logger(self):
+        return self.executor.logger
+
+    def setup(self, runner):
+        pass
+
+    def teardown(self):
+        pass
+
+    def wait(self):
+        pass
diff --git a/testing/web-platform/harness/wptrunner/executors/executormarionette.py b/testing/web-platform/harness/wptrunner/executors/executormarionette.py
new file mode 100644
index 000000000..e212c2945
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/executormarionette.py
@@ -0,0 +1,595 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import hashlib
+import httplib
+import os
+import socket
+import threading
+import time
+import traceback
+import urlparse
+import uuid
+from collections import defaultdict
+
+from ..wpttest import WdspecResult, WdspecSubtestResult
+
+errors = None
+marionette = None
+webdriver = None
+
+here = os.path.join(os.path.split(__file__)[0])
+
+from . import pytestrunner
+from .base import (ExecutorException,
+                   Protocol,
+                   RefTestExecutor,
+                   RefTestImplementation,
+                   TestExecutor,
+                   TestharnessExecutor,
+                   testharness_result_converter,
+                   reftest_result_converter,
+                   strip_server,
+                   WdspecExecutor)
+from ..testrunner import Stop
+from ..webdriver_server import GeckoDriverServer
+
+# Extra timeout to use after internal test timeout at which the harness
+# should force a timeout
+extra_timeout = 5 # seconds
+
+
+def do_delayed_imports():
+    global errors, marionette, webdriver
+
+    # Marionette client used to be called marionette, recently it changed
+    # to marionette_driver for unfathomable reasons
+    try:
+        import marionette
+        from marionette import errors
+    except ImportError:
+        from marionette_driver import marionette, errors
+
+    import webdriver
+
+
+class MarionetteProtocol(Protocol):
+    def __init__(self, executor, browser):
+        do_delayed_imports()
+
+        Protocol.__init__(self, executor, browser)
+        self.marionette = None
+        self.marionette_port = browser.marionette_port
+        self.timeout = None
+        self.runner_handle = None
+
+    def setup(self, runner):
+        """Connect to browser via Marionette."""
+        Protocol.setup(self, runner)
+
+        self.logger.debug("Connecting to Marionette on port %i" % self.marionette_port)
+        self.marionette = marionette.Marionette(host='localhost',
+                                                port=self.marionette_port,
+                                                socket_timeout=None)
+
+        # XXX Move this timeout somewhere
+        self.logger.debug("Waiting for Marionette connection")
+        while True:
+            success = self.marionette.wait_for_port(60)
+            #When running in a debugger wait indefinitely for firefox to start
+            if success or self.executor.debug_info is None:
+                break
+
+        session_started = False
+        if success:
+            try:
+                self.logger.debug("Starting Marionette session")
+                self.marionette.start_session()
+            except Exception as e:
+                self.logger.warning("Starting marionette session failed: %s" % e)
+            else:
+                self.logger.debug("Marionette session started")
+                session_started = True
+
+        if not success or not session_started:
+            self.logger.warning("Failed to connect to Marionette")
+            self.executor.runner.send_message("init_failed")
+        else:
+            try:
+                self.after_connect()
+            except Exception:
+                self.logger.warning("Post-connection steps failed")
+                self.logger.error(traceback.format_exc())
+                self.executor.runner.send_message("init_failed")
+            else:
+                self.executor.runner.send_message("init_succeeded")
+
+    def teardown(self):
+        try:
+            self.marionette.delete_session()
+        except Exception:
+            # This is typically because the session never started
+            pass
+        del self.marionette
+
+    @property
+    def is_alive(self):
+        """Check if the Marionette connection is still active."""
+        try:
+            self.marionette.current_window_handle
+        except Exception:
+            return False
+        return True
+
+    def after_connect(self):
+        self.load_runner("http")
+
+    def set_timeout(self, timeout):
+        """Set the Marionette script timeout.
+
+        :param timeout: Script timeout in seconds
+
+        """
+        self.marionette.timeout.script = timeout
+        self.timeout = timeout
+
+    def load_runner(self, protocol):
+        # Check if we previously had a test window open, and if we did make sure it's closed
+        self.marionette.execute_script("if (window.wrappedJSObject.win) {window.wrappedJSObject.win.close()}")
+        url = urlparse.urljoin(self.executor.server_url(protocol), "/testharness_runner.html")
+        self.logger.debug("Loading %s" % url)
+        self.runner_handle = self.marionette.current_window_handle
+        try:
+            self.marionette.navigate(url)
+        except Exception as e:
+            self.logger.critical(
+                "Loading initial page %s failed. Ensure that the "
+                "there are no other programs bound to this port and "
+                "that your firewall rules or network setup does not "
+                "prevent access.\e%s" % (url, traceback.format_exc(e)))
+        self.marionette.execute_script(
+            "document.title = '%s'" % threading.current_thread().name.replace("'", '"'))
+
+    def close_old_windows(self, protocol):
+        handles = self.marionette.window_handles
+        runner_handle = None
+        try:
+            handles.remove(self.runner_handle)
+            runner_handle = self.runner_handle
+        except ValueError:
+            # The runner window probably changed id but we can restore it
+            # This isn't supposed to happen, but marionette ids are not yet stable
+            # We assume that the first handle returned corresponds to the runner,
+            # but it hopefully doesn't matter too much if that assumption is
+            # wrong since we reload the runner in that tab anyway.
+            runner_handle = handles.pop(0)
+
+        for handle in handles:
+            self.marionette.switch_to_window(handle)
+            self.marionette.close()
+
+        self.marionette.switch_to_window(runner_handle)
+        if runner_handle != self.runner_handle:
+            self.load_runner(protocol)
+
+    def wait(self):
+        socket_timeout = self.marionette.client.sock.gettimeout()
+        if socket_timeout:
+            self.marionette.timeout.script = socket_timeout / 2
+
+        while True:
+            try:
+                self.marionette.execute_async_script("")
+            except errors.ScriptTimeoutException:
+                self.logger.debug("Script timed out")
+                pass
+            except (socket.timeout, IOError):
+                self.logger.debug("Socket closed")
+                break
+            except Exception as e:
+                self.logger.error(traceback.format_exc(e))
+                break
+
+    def on_environment_change(self, old_environment, new_environment):
+        #Unset all the old prefs
+        for name in old_environment.get("prefs", {}).iterkeys():
+            value = self.executor.original_pref_values[name]
+            if value is None:
+                self.clear_user_pref(name)
+            else:
+                self.set_pref(name, value)
+
+        for name, value in new_environment.get("prefs", {}).iteritems():
+            self.executor.original_pref_values[name] = self.get_pref(name)
+            self.set_pref(name, value)
+
+    def set_pref(self, name, value):
+        if value.lower() not in ("true", "false"):
+            try:
+                int(value)
+            except ValueError:
+                value = "'%s'" % value
+        else:
+            value = value.lower()
+
+        self.logger.info("Setting pref %s (%s)" % (name, value))
+
+        script = """
+            let prefInterface = Components.classes["@mozilla.org/preferences-service;1"]
+                                          .getService(Components.interfaces.nsIPrefBranch);
+            let pref = '%s';
+            let type = prefInterface.getPrefType(pref);
+            let value = %s;
+            switch(type) {
+                case prefInterface.PREF_STRING:
+                    prefInterface.setCharPref(pref, value);
+                    break;
+                case prefInterface.PREF_BOOL:
+                    prefInterface.setBoolPref(pref, value);
+                    break;
+                case prefInterface.PREF_INT:
+                    prefInterface.setIntPref(pref, value);
+                    break;
+            }
+            """ % (name, value)
+        with self.marionette.using_context(self.marionette.CONTEXT_CHROME):
+            self.marionette.execute_script(script)
+
+    def clear_user_pref(self, name):
+        self.logger.info("Clearing pref %s" % (name))
+        script = """
+            let prefInterface = Components.classes["@mozilla.org/preferences-service;1"]
+                                          .getService(Components.interfaces.nsIPrefBranch);
+            let pref = '%s';
+            prefInterface.clearUserPref(pref);
+            """ % name
+        with self.marionette.using_context(self.marionette.CONTEXT_CHROME):
+            self.marionette.execute_script(script)
+
+    def get_pref(self, name):
+        script = """
+            let prefInterface = Components.classes["@mozilla.org/preferences-service;1"]
+                                          .getService(Components.interfaces.nsIPrefBranch);
+            let pref = '%s';
+            let type = prefInterface.getPrefType(pref);
+            switch(type) {
+                case prefInterface.PREF_STRING:
+                    return prefInterface.getCharPref(pref);
+                case prefInterface.PREF_BOOL:
+                    return prefInterface.getBoolPref(pref);
+                case prefInterface.PREF_INT:
+                    return prefInterface.getIntPref(pref);
+                case prefInterface.PREF_INVALID:
+                    return null;
+            }
+            """ % name
+        with self.marionette.using_context(self.marionette.CONTEXT_CHROME):
+            self.marionette.execute_script(script)
+
+
+class RemoteMarionetteProtocol(Protocol):
+    def __init__(self, executor, browser):
+        do_delayed_imports()
+        Protocol.__init__(self, executor, browser)
+        self.session = None
+        self.webdriver_binary = executor.webdriver_binary
+        self.marionette_port = browser.marionette_port
+        self.server = None
+
+    def setup(self, runner):
+        """Connect to browser via the Marionette HTTP server."""
+        try:
+            self.server = GeckoDriverServer(
+                self.logger, self.marionette_port, binary=self.webdriver_binary)
+            self.server.start(block=False)
+            self.logger.info(
+                "WebDriver HTTP server listening at %s" % self.server.url)
+
+            self.logger.info(
+                "Establishing new WebDriver session with %s" % self.server.url)
+            self.session = webdriver.Session(
+                self.server.host, self.server.port, self.server.base_path)
+        except Exception:
+            self.logger.error(traceback.format_exc())
+            self.executor.runner.send_message("init_failed")
+        else:
+            self.executor.runner.send_message("init_succeeded")
+
+    def teardown(self):
+        try:
+            if self.session.session_id is not None:
+                self.session.end()
+        except Exception:
+            pass
+        if self.server is not None and self.server.is_alive:
+            self.server.stop()
+
+    @property
+    def is_alive(self):
+        """Test that the Marionette connection is still alive.
+
+        Because the remote communication happens over HTTP we need to
+        make an explicit request to the remote.  It is allowed for
+        WebDriver spec tests to not have a WebDriver session, since this
+        may be what is tested.
+
+        An HTTP request to an invalid path that results in a 404 is
+        proof enough to us that the server is alive and kicking.
+        """
+        conn = httplib.HTTPConnection(self.server.host, self.server.port)
+        conn.request("HEAD", self.server.base_path + "invalid")
+        res = conn.getresponse()
+        return res.status == 404
+
+
+class ExecuteAsyncScriptRun(object):
+    def __init__(self, logger, func, protocol, url, timeout):
+        self.logger = logger
+        self.result = (None, None)
+        self.protocol = protocol
+        self.marionette = protocol.marionette
+        self.func = func
+        self.url = url
+        self.timeout = timeout
+        self.result_flag = threading.Event()
+
+    def run(self):
+        timeout = self.timeout
+
+        try:
+            if timeout is not None:
+                if timeout + extra_timeout != self.protocol.timeout:
+                    self.protocol.set_timeout(timeout + extra_timeout)
+            else:
+                # We just want it to never time out, really, but marionette doesn't
+                # make that possible. It also seems to time out immediately if the
+                # timeout is set too high. This works at least.
+                self.protocol.set_timeout(2**28 - 1)
+        except IOError:
+            self.logger.error("Lost marionette connection before starting test")
+            return Stop
+
+        executor = threading.Thread(target = self._run)
+        executor.start()
+
+        if timeout is not None:
+            wait_timeout = timeout + 2 * extra_timeout
+        else:
+            wait_timeout = None
+
+        flag = self.result_flag.wait(wait_timeout)
+        if self.result[1] is None:
+            self.logger.debug("Timed out waiting for a result")
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+        return self.result
+
+    def _run(self):
+        try:
+            self.result = True, self.func(self.marionette, self.url, self.timeout)
+        except errors.ScriptTimeoutException:
+            self.logger.debug("Got a marionette timeout")
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+        except (socket.timeout, IOError):
+            # This can happen on a crash
+            # Also, should check after the test if the firefox process is still running
+            # and otherwise ignore any other result and set it to crash
+            self.result = False, ("CRASH", None)
+        except Exception as e:
+            message = getattr(e, "message", "")
+            if message:
+                message += "\n"
+            message += traceback.format_exc(e)
+            self.result = False, ("ERROR", e)
+
+        finally:
+            self.result_flag.set()
+
+
+class MarionetteTestharnessExecutor(TestharnessExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 close_after_done=True, debug_info=None, **kwargs):
+        """Marionette-based executor for testharness.js tests"""
+        TestharnessExecutor.__init__(self, browser, server_config,
+                                     timeout_multiplier=timeout_multiplier,
+                                     debug_info=debug_info)
+
+        self.protocol = MarionetteProtocol(self, browser)
+        self.script = open(os.path.join(here, "testharness_marionette.js")).read()
+        self.close_after_done = close_after_done
+        self.window_id = str(uuid.uuid4())
+
+        self.original_pref_values = {}
+
+        if marionette is None:
+            do_delayed_imports()
+
+    def is_alive(self):
+        return self.protocol.is_alive
+
+    def on_environment_change(self, new_environment):
+        self.protocol.on_environment_change(self.last_environment, new_environment)
+
+        if new_environment["protocol"] != self.last_environment["protocol"]:
+            self.protocol.load_runner(new_environment["protocol"])
+
+    def do_test(self, test):
+        timeout = (test.timeout * self.timeout_multiplier if self.debug_info is None
+                   else None)
+
+        success, data = ExecuteAsyncScriptRun(self.logger,
+                                              self.do_testharness,
+                                              self.protocol,
+                                              self.test_url(test),
+                                              timeout).run()
+        if success:
+            return self.convert_result(test, data)
+
+        return (test.result_cls(*data), [])
+
+    def do_testharness(self, marionette, url, timeout):
+        if self.close_after_done:
+            marionette.execute_script("if (window.wrappedJSObject.win) {window.wrappedJSObject.win.close()}")
+            self.protocol.close_old_windows(self.protocol)
+
+        if timeout is not None:
+            timeout_ms = str(timeout * 1000)
+        else:
+            timeout_ms = "null"
+
+        script = self.script % {"abs_url": url,
+                                "url": strip_server(url),
+                                "window_id": self.window_id,
+                                "timeout_multiplier": self.timeout_multiplier,
+                                "timeout": timeout_ms,
+                                "explicit_timeout": timeout is None}
+
+        rv = marionette.execute_async_script(script, new_sandbox=False)
+        return rv
+
+
+class MarionetteRefTestExecutor(RefTestExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 screenshot_cache=None, close_after_done=True,
+                 debug_info=None, **kwargs):
+
+        """Marionette-based executor for reftests"""
+        RefTestExecutor.__init__(self,
+                                 browser,
+                                 server_config,
+                                 screenshot_cache=screenshot_cache,
+                                 timeout_multiplier=timeout_multiplier,
+                                 debug_info=debug_info)
+        self.protocol = MarionetteProtocol(self, browser)
+        self.implementation = RefTestImplementation(self)
+        self.close_after_done = close_after_done
+        self.has_window = False
+        self.original_pref_values = {}
+
+        with open(os.path.join(here, "reftest.js")) as f:
+            self.script = f.read()
+        with open(os.path.join(here, "reftest-wait.js")) as f:
+            self.wait_script = f.read()
+
+    def is_alive(self):
+        return self.protocol.is_alive
+
+    def on_environment_change(self, new_environment):
+        self.protocol.on_environment_change(self.last_environment, new_environment)
+
+    def do_test(self, test):
+        if self.close_after_done and self.has_window:
+            self.protocol.marionette.close()
+            self.protocol.marionette.switch_to_window(
+                self.protocol.marionette.window_handles[-1])
+            self.has_window = False
+
+        if not self.has_window:
+            self.protocol.marionette.execute_script(self.script)
+            self.protocol.marionette.switch_to_window(self.protocol.marionette.window_handles[-1])
+            self.has_window = True
+
+        result = self.implementation.run_test(test)
+        return self.convert_result(test, result)
+
+    def screenshot(self, test, viewport_size, dpi):
+        # https://github.com/w3c/wptrunner/issues/166
+        assert viewport_size is None
+        assert dpi is None
+
+        timeout =  self.timeout_multiplier * test.timeout if self.debug_info is None else None
+
+        test_url = self.test_url(test)
+
+        return ExecuteAsyncScriptRun(self.logger,
+                             self._screenshot,
+                             self.protocol,
+                             test_url,
+                             timeout).run()
+
+    def _screenshot(self, marionette, url, timeout):
+        marionette.navigate(url)
+
+        marionette.execute_async_script(self.wait_script)
+
+        screenshot = marionette.screenshot()
+        # strip off the data:img/png, part of the url
+        if screenshot.startswith("data:image/png;base64,"):
+            screenshot = screenshot.split(",", 1)[1]
+
+        return screenshot
+
+
+class WdspecRun(object):
+    def __init__(self, func, session, path, timeout):
+        self.func = func
+        self.result = (None, None)
+        self.session = session
+        self.path = path
+        self.timeout = timeout
+        self.result_flag = threading.Event()
+
+    def run(self):
+        """Runs function in a thread and interrupts it if it exceeds the
+        given timeout.  Returns (True, (Result, [SubtestResult ...])) in
+        case of success, or (False, (status, extra information)) in the
+        event of failure.
+        """
+
+        executor = threading.Thread(target=self._run)
+        executor.start()
+
+        flag = self.result_flag.wait(self.timeout)
+        if self.result[1] is None:
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+
+        return self.result
+
+    def _run(self):
+        try:
+            self.result = True, self.func(self.session, self.path, self.timeout)
+        except (socket.timeout, IOError):
+            self.result = False, ("CRASH", None)
+        except Exception as e:
+            message = getattr(e, "message")
+            if message:
+                message += "\n"
+            message += traceback.format_exc(e)
+            self.result = False, ("ERROR", message)
+        finally:
+            self.result_flag.set()
+
+
+class MarionetteWdspecExecutor(WdspecExecutor):
+    def __init__(self, browser, server_config, webdriver_binary,
+                 timeout_multiplier=1, close_after_done=True, debug_info=None):
+        WdspecExecutor.__init__(self, browser, server_config,
+                                timeout_multiplier=timeout_multiplier,
+                                debug_info=debug_info)
+        self.webdriver_binary = webdriver_binary
+        self.protocol = RemoteMarionetteProtocol(self, browser)
+
+    def is_alive(self):
+        return self.protocol.is_alive
+
+    def on_environment_change(self, new_environment):
+        pass
+
+    def do_test(self, test):
+        timeout = test.timeout * self.timeout_multiplier + extra_timeout
+
+        success, data = WdspecRun(self.do_wdspec,
+                                  self.protocol.session,
+                                  test.abs_path,
+                                  timeout).run()
+
+        if success:
+            return self.convert_result(test, data)
+
+        return (test.result_cls(*data), [])
+
+    def do_wdspec(self, session, path, timeout):
+        harness_result = ("OK", None)
+        subtest_results = pytestrunner.run(
+            path, session, self.server_url, timeout=timeout)
+        return (harness_result, subtest_results)
diff --git a/testing/web-platform/harness/wptrunner/executors/executorselenium.py b/testing/web-platform/harness/wptrunner/executors/executorselenium.py
new file mode 100644
index 000000000..b8b209a77
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/executorselenium.py
@@ -0,0 +1,271 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+import socket
+import sys
+import threading
+import time
+import traceback
+import urlparse
+import uuid
+
+from .base import (ExecutorException,
+                   Protocol,
+                   RefTestExecutor,
+                   RefTestImplementation,
+                   TestExecutor,
+                   TestharnessExecutor,
+                   testharness_result_converter,
+                   reftest_result_converter,
+                   strip_server)
+from ..testrunner import Stop
+
+
+here = os.path.join(os.path.split(__file__)[0])
+
+webdriver = None
+exceptions = None
+
+extra_timeout = 5
+
+def do_delayed_imports():
+    global webdriver
+    global exceptions
+    from selenium import webdriver
+    from selenium.common import exceptions
+
+
+class SeleniumProtocol(Protocol):
+    def __init__(self, executor, browser, capabilities, **kwargs):
+        do_delayed_imports()
+
+        Protocol.__init__(self, executor, browser)
+        self.capabilities = capabilities
+        self.url = browser.webdriver_url
+        self.webdriver = None
+
+    def setup(self, runner):
+        """Connect to browser via Selenium's WebDriver implementation."""
+        self.runner = runner
+        self.logger.debug("Connecting to Selenium on URL: %s" % self.url)
+
+        session_started = False
+        try:
+            self.webdriver = webdriver.Remote(
+                self.url, desired_capabilities=self.capabilities)
+        except:
+            self.logger.warning(
+                "Connecting to Selenium failed:\n%s" % traceback.format_exc())
+        else:
+            self.logger.debug("Selenium session started")
+            session_started = True
+
+        if not session_started:
+            self.logger.warning("Failed to connect to Selenium")
+            self.executor.runner.send_message("init_failed")
+        else:
+            try:
+                self.after_connect()
+            except:
+                print >> sys.stderr, traceback.format_exc()
+                self.logger.warning(
+                    "Failed to connect to navigate initial page")
+                self.executor.runner.send_message("init_failed")
+            else:
+                self.executor.runner.send_message("init_succeeded")
+
+    def teardown(self):
+        self.logger.debug("Hanging up on Selenium session")
+        try:
+            self.webdriver.quit()
+        except:
+            pass
+        del self.webdriver
+
+    def is_alive(self):
+        try:
+            # Get a simple property over the connection
+            self.webdriver.current_window_handle
+        # TODO what exception?
+        except (socket.timeout, exceptions.ErrorInResponseException):
+            return False
+        return True
+
+    def after_connect(self):
+        self.load_runner("http")
+
+    def load_runner(self, protocol):
+        url = urlparse.urljoin(self.executor.server_url(protocol),
+                               "/testharness_runner.html")
+        self.logger.debug("Loading %s" % url)
+        self.webdriver.get(url)
+        self.webdriver.execute_script("document.title = '%s'" %
+                                      threading.current_thread().name.replace("'", '"'))
+
+    def wait(self):
+        while True:
+            try:
+                self.webdriver.execute_async_script("");
+            except exceptions.TimeoutException:
+                pass
+            except (socket.timeout, exceptions.NoSuchWindowException,
+                    exceptions.ErrorInResponseException, IOError):
+                break
+            except Exception as e:
+                self.logger.error(traceback.format_exc(e))
+                break
+
+
+class SeleniumRun(object):
+    def __init__(self, func, webdriver, url, timeout):
+        self.func = func
+        self.result = None
+        self.webdriver = webdriver
+        self.url = url
+        self.timeout = timeout
+        self.result_flag = threading.Event()
+
+    def run(self):
+        timeout = self.timeout
+
+        try:
+            self.webdriver.set_script_timeout((timeout + extra_timeout) * 1000)
+        except exceptions.ErrorInResponseException:
+            self.logger.error("Lost WebDriver connection")
+            return Stop
+
+        executor = threading.Thread(target=self._run)
+        executor.start()
+
+        flag = self.result_flag.wait(timeout + 2 * extra_timeout)
+        if self.result is None:
+            assert not flag
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+
+        return self.result
+
+    def _run(self):
+        try:
+            self.result = True, self.func(self.webdriver, self.url, self.timeout)
+        except exceptions.TimeoutException:
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+        except (socket.timeout, exceptions.ErrorInResponseException):
+            self.result = False, ("CRASH", None)
+        except Exception as e:
+            message = getattr(e, "message", "")
+            if message:
+                message += "\n"
+            message += traceback.format_exc(e)
+            self.result = False, ("ERROR", e)
+        finally:
+            self.result_flag.set()
+
+
+class SeleniumTestharnessExecutor(TestharnessExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 close_after_done=True, capabilities=None, debug_info=None):
+        """Selenium-based executor for testharness.js tests"""
+        TestharnessExecutor.__init__(self, browser, server_config,
+                                     timeout_multiplier=timeout_multiplier,
+                                     debug_info=debug_info)
+        self.protocol = SeleniumProtocol(self, browser, capabilities)
+        with open(os.path.join(here, "testharness_webdriver.js")) as f:
+            self.script = f.read()
+        self.close_after_done = close_after_done
+        self.window_id = str(uuid.uuid4())
+
+    def is_alive(self):
+        return self.protocol.is_alive()
+
+    def on_protocol_change(self, new_protocol):
+        self.protocol.load_runner(new_protocol)
+
+    def do_test(self, test):
+        url = self.test_url(test)
+
+        success, data = SeleniumRun(self.do_testharness,
+                                    self.protocol.webdriver,
+                                    url,
+                                    test.timeout * self.timeout_multiplier).run()
+
+        if success:
+            return self.convert_result(test, data)
+
+        return (test.result_cls(*data), [])
+
+    def do_testharness(self, webdriver, url, timeout):
+        return webdriver.execute_async_script(
+            self.script % {"abs_url": url,
+                           "url": strip_server(url),
+                           "window_id": self.window_id,
+                           "timeout_multiplier": self.timeout_multiplier,
+                           "timeout": timeout * 1000})
+
+class SeleniumRefTestExecutor(RefTestExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 screenshot_cache=None, close_after_done=True,
+                 debug_info=None, capabilities=None):
+        """Selenium WebDriver-based executor for reftests"""
+        RefTestExecutor.__init__(self,
+                                 browser,
+                                 server_config,
+                                 screenshot_cache=screenshot_cache,
+                                 timeout_multiplier=timeout_multiplier,
+                                 debug_info=debug_info)
+        self.protocol = SeleniumProtocol(self, browser,
+                                         capabilities=capabilities)
+        self.implementation = RefTestImplementation(self)
+        self.close_after_done = close_after_done
+        self.has_window = False
+
+        with open(os.path.join(here, "reftest.js")) as f:
+            self.script = f.read()
+        with open(os.path.join(here, "reftest-wait_webdriver.js")) as f:
+            self.wait_script = f.read()
+
+    def is_alive(self):
+        return self.protocol.is_alive()
+
+    def do_test(self, test):
+        self.logger.info("Test requires OS-level window focus")
+
+        if self.close_after_done and self.has_window:
+            self.protocol.webdriver.close()
+            self.protocol.webdriver.switch_to_window(
+                self.protocol.webdriver.window_handles[-1])
+            self.has_window = False
+
+        if not self.has_window:
+            self.protocol.webdriver.execute_script(self.script)
+            self.protocol.webdriver.switch_to_window(
+                self.protocol.webdriver.window_handles[-1])
+            self.has_window = True
+
+        result = self.implementation.run_test(test)
+
+        return self.convert_result(test, result)
+
+    def screenshot(self, test, viewport_size, dpi):
+        # https://github.com/w3c/wptrunner/issues/166
+        assert viewport_size is None
+        assert dpi is None
+
+        return SeleniumRun(self._screenshot,
+                           self.protocol.webdriver,
+                           self.test_url(test),
+                           test.timeout).run()
+
+    def _screenshot(self, webdriver, url, timeout):
+        webdriver.get(url)
+
+        webdriver.execute_async_script(self.wait_script)
+
+        screenshot = webdriver.get_screenshot_as_base64()
+
+        # strip off the data:img/png, part of the url
+        if screenshot.startswith("data:image/png;base64,"):
+            screenshot = screenshot.split(",", 1)[1]
+
+        return screenshot
diff --git a/testing/web-platform/harness/wptrunner/executors/executorservo.py b/testing/web-platform/harness/wptrunner/executors/executorservo.py
new file mode 100644
index 000000000..068061b95
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/executorservo.py
@@ -0,0 +1,275 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import base64
+import hashlib
+import json
+import os
+import subprocess
+import tempfile
+import threading
+import urlparse
+import uuid
+from collections import defaultdict
+
+from mozprocess import ProcessHandler
+
+from .base import (ExecutorException,
+                   Protocol,
+                   RefTestImplementation,
+                   testharness_result_converter,
+                   reftest_result_converter)
+from .process import ProcessTestExecutor
+from ..browsers.base import browser_command
+render_arg = None
+
+
+def do_delayed_imports():
+    global render_arg
+    from ..browsers.servo import render_arg
+
+hosts_text = """127.0.0.1 web-platform.test
+127.0.0.1 www.web-platform.test
+127.0.0.1 www1.web-platform.test
+127.0.0.1 www2.web-platform.test
+127.0.0.1 xn--n8j6ds53lwwkrqhv28a.web-platform.test
+127.0.0.1 xn--lve-6lad.web-platform.test
+"""
+
+def make_hosts_file():
+    hosts_fd, hosts_path = tempfile.mkstemp()
+    with os.fdopen(hosts_fd, "w") as f:
+        f.write(hosts_text)
+    return hosts_path
+
+
+class ServoTestharnessExecutor(ProcessTestExecutor):
+    convert_result = testharness_result_converter
+
+    def __init__(self, browser, server_config, timeout_multiplier=1, debug_info=None,
+                 pause_after_test=False):
+        do_delayed_imports()
+        ProcessTestExecutor.__init__(self, browser, server_config,
+                                     timeout_multiplier=timeout_multiplier,
+                                     debug_info=debug_info)
+        self.pause_after_test = pause_after_test
+        self.result_data = None
+        self.result_flag = None
+        self.protocol = Protocol(self, browser)
+        self.hosts_path = make_hosts_file()
+
+    def teardown(self):
+        try:
+            os.unlink(self.hosts_path)
+        except OSError:
+            pass
+        ProcessTestExecutor.teardown(self)
+
+    def do_test(self, test):
+        self.result_data = None
+        self.result_flag = threading.Event()
+
+        args = [render_arg(self.browser.render_backend), "--hard-fail", "-u", "Servo/wptrunner",
+                "-Z", "replace-surrogates", "-z", self.test_url(test)]
+        for stylesheet in self.browser.user_stylesheets:
+            args += ["--user-stylesheet", stylesheet]
+        for pref, value in test.environment.get('prefs', {}).iteritems():
+            args += ["--pref", "%s=%s" % (pref, value)]
+        args += self.browser.binary_args
+        debug_args, command = browser_command(self.binary, args, self.debug_info)
+
+        self.command = command
+
+        if self.pause_after_test:
+            self.command.remove("-z")
+
+        self.command = debug_args + self.command
+
+        env = os.environ.copy()
+        env["HOST_FILE"] = self.hosts_path
+        env["RUST_BACKTRACE"] = "1"
+
+
+        if not self.interactive:
+            self.proc = ProcessHandler(self.command,
+                                       processOutputLine=[self.on_output],
+                                       onFinish=self.on_finish,
+                                       env=env,
+                                       storeOutput=False)
+            self.proc.run()
+        else:
+            self.proc = subprocess.Popen(self.command, env=env)
+
+        try:
+            timeout = test.timeout * self.timeout_multiplier
+
+            # Now wait to get the output we expect, or until we reach the timeout
+            if not self.interactive and not self.pause_after_test:
+                wait_timeout = timeout + 5
+                self.result_flag.wait(wait_timeout)
+            else:
+                wait_timeout = None
+                self.proc.wait()
+
+            proc_is_running = True
+
+            if self.result_flag.is_set():
+                if self.result_data is not None:
+                    result = self.convert_result(test, self.result_data)
+                else:
+                    self.proc.wait()
+                    result = (test.result_cls("CRASH", None), [])
+                    proc_is_running = False
+            else:
+                result = (test.result_cls("TIMEOUT", None), [])
+
+
+            if proc_is_running:
+                if self.pause_after_test:
+                    self.logger.info("Pausing until the browser exits")
+                    self.proc.wait()
+                else:
+                    self.proc.kill()
+        except KeyboardInterrupt:
+            self.proc.kill()
+            raise
+
+        return result
+
+    def on_output(self, line):
+        prefix = "ALERT: RESULT: "
+        line = line.decode("utf8", "replace")
+        if line.startswith(prefix):
+            self.result_data = json.loads(line[len(prefix):])
+            self.result_flag.set()
+        else:
+            if self.interactive:
+                print line
+            else:
+                self.logger.process_output(self.proc.pid,
+                                           line,
+                                           " ".join(self.command))
+
+    def on_finish(self):
+        self.result_flag.set()
+
+
+class TempFilename(object):
+    def __init__(self, directory):
+        self.directory = directory
+        self.path = None
+
+    def __enter__(self):
+        self.path = os.path.join(self.directory, str(uuid.uuid4()))
+        return self.path
+
+    def __exit__(self, *args, **kwargs):
+        try:
+            os.unlink(self.path)
+        except OSError:
+            pass
+
+
+class ServoRefTestExecutor(ProcessTestExecutor):
+    convert_result = reftest_result_converter
+
+    def __init__(self, browser, server_config, binary=None, timeout_multiplier=1,
+                 screenshot_cache=None, debug_info=None, pause_after_test=False):
+        do_delayed_imports()
+        ProcessTestExecutor.__init__(self,
+                                     browser,
+                                     server_config,
+                                     timeout_multiplier=timeout_multiplier,
+                                     debug_info=debug_info)
+
+        self.protocol = Protocol(self, browser)
+        self.screenshot_cache = screenshot_cache
+        self.implementation = RefTestImplementation(self)
+        self.tempdir = tempfile.mkdtemp()
+        self.hosts_path = make_hosts_file()
+
+    def teardown(self):
+        try:
+            os.unlink(self.hosts_path)
+        except OSError:
+            pass
+        os.rmdir(self.tempdir)
+        ProcessTestExecutor.teardown(self)
+
+    def screenshot(self, test, viewport_size, dpi):
+        full_url = self.test_url(test)
+
+        with TempFilename(self.tempdir) as output_path:
+            debug_args, command = browser_command(
+                self.binary,
+                [render_arg(self.browser.render_backend), "--hard-fail", "--exit",
+                 "-u", "Servo/wptrunner", "-Z", "disable-text-aa,load-webfonts-synchronously,replace-surrogates",
+                 "--output=%s" % output_path, full_url],
+                self.debug_info)
+
+            for stylesheet in self.browser.user_stylesheets:
+                command += ["--user-stylesheet", stylesheet]
+
+            for pref in test.environment.get('prefs', {}):
+                command += ["--pref", pref]
+
+            if viewport_size:
+                command += ["--resolution", viewport_size]
+
+            if dpi:
+                command += ["--device-pixel-ratio", dpi]
+
+            self.command = debug_args + command
+
+            env = os.environ.copy()
+            env["HOST_FILE"] = self.hosts_path
+            env["RUST_BACKTRACE"] = "1"
+
+            if not self.interactive:
+                self.proc = ProcessHandler(self.command,
+                                           processOutputLine=[self.on_output],
+                                           env=env)
+
+
+                try:
+                    self.proc.run()
+                    timeout = test.timeout * self.timeout_multiplier + 5
+                    rv = self.proc.wait(timeout=timeout)
+                except KeyboardInterrupt:
+                    self.proc.kill()
+                    raise
+            else:
+                self.proc = subprocess.Popen(self.command,
+                                             env=env)
+                try:
+                    rv = self.proc.wait()
+                except KeyboardInterrupt:
+                    self.proc.kill()
+                    raise
+
+            if rv is None:
+                self.proc.kill()
+                return False, ("EXTERNAL-TIMEOUT", None)
+
+            if rv != 0 or not os.path.exists(output_path):
+                return False, ("CRASH", None)
+
+            with open(output_path) as f:
+                # Might need to strip variable headers or something here
+                data = f.read()
+                return True, base64.b64encode(data)
+
+    def do_test(self, test):
+        result = self.implementation.run_test(test)
+
+        return self.convert_result(test, result)
+
+    def on_output(self, line):
+        line = line.decode("utf8", "replace")
+        if self.interactive:
+            print line
+        else:
+            self.logger.process_output(self.proc.pid,
+                                       line,
+                                       " ".join(self.command))
diff --git a/testing/web-platform/harness/wptrunner/executors/executorservodriver.py b/testing/web-platform/harness/wptrunner/executors/executorservodriver.py
new file mode 100644
index 000000000..fceeb58fa
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/executorservodriver.py
@@ -0,0 +1,262 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import json
+import os
+import socket
+import threading
+import time
+import traceback
+
+from .base import (Protocol,
+                   RefTestExecutor,
+                   RefTestImplementation,
+                   TestharnessExecutor,
+                   strip_server)
+from .. import webdriver
+from ..testrunner import Stop
+
+webdriver = None
+
+here = os.path.join(os.path.split(__file__)[0])
+
+extra_timeout = 5
+
+
+def do_delayed_imports():
+    global webdriver
+    import webdriver
+
+
+class ServoWebDriverProtocol(Protocol):
+    def __init__(self, executor, browser, capabilities, **kwargs):
+        do_delayed_imports()
+        Protocol.__init__(self, executor, browser)
+        self.capabilities = capabilities
+        self.host = browser.webdriver_host
+        self.port = browser.webdriver_port
+        self.session = None
+
+    def setup(self, runner):
+        """Connect to browser via WebDriver."""
+        self.runner = runner
+
+        url = "http://%s:%d" % (self.host, self.port)
+        session_started = False
+        try:
+            self.session = webdriver.Session(self.host, self.port,
+                extension=webdriver.servo.ServoCommandExtensions)
+            self.session.start()
+        except:
+            self.logger.warning(
+                "Connecting with WebDriver failed:\n%s" % traceback.format_exc())
+        else:
+            self.logger.debug("session started")
+            session_started = True
+
+        if not session_started:
+            self.logger.warning("Failed to connect via WebDriver")
+            self.executor.runner.send_message("init_failed")
+        else:
+            self.executor.runner.send_message("init_succeeded")
+
+    def teardown(self):
+        self.logger.debug("Hanging up on WebDriver session")
+        try:
+            self.session.end()
+        except:
+            pass
+
+    def is_alive(self):
+        try:
+            # Get a simple property over the connection
+            self.session.window_handle
+        # TODO what exception?
+        except Exception:
+            return False
+        return True
+
+    def after_connect(self):
+        pass
+
+    def wait(self):
+        while True:
+            try:
+                self.session.execute_async_script("")
+            except webdriver.TimeoutException:
+                pass
+            except (socket.timeout, IOError):
+                break
+            except Exception as e:
+                self.logger.error(traceback.format_exc(e))
+                break
+
+    def on_environment_change(self, old_environment, new_environment):
+        #Unset all the old prefs
+        self.session.extension.reset_prefs(*old_environment.get("prefs", {}).keys())
+        self.session.extension.set_prefs(new_environment.get("prefs", {}))
+
+
+class ServoWebDriverRun(object):
+    def __init__(self, func, session, url, timeout, current_timeout=None):
+        self.func = func
+        self.result = None
+        self.session = session
+        self.url = url
+        self.timeout = timeout
+        self.result_flag = threading.Event()
+
+    def run(self):
+        executor = threading.Thread(target=self._run)
+        executor.start()
+
+        flag = self.result_flag.wait(self.timeout + extra_timeout)
+        if self.result is None:
+            assert not flag
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+
+        return self.result
+
+    def _run(self):
+        try:
+            self.result = True, self.func(self.session, self.url, self.timeout)
+        except webdriver.TimeoutException:
+            self.result = False, ("EXTERNAL-TIMEOUT", None)
+        except (socket.timeout, IOError):
+            self.result = False, ("CRASH", None)
+        except Exception as e:
+            message = getattr(e, "message", "")
+            if message:
+                message += "\n"
+            message += traceback.format_exc(e)
+            self.result = False, ("ERROR", e)
+        finally:
+            self.result_flag.set()
+
+
+def timeout_func(timeout):
+    if timeout:
+        t0 = time.time()
+        return lambda: time.time() - t0 > timeout + extra_timeout
+    else:
+        return lambda: False
+
+
+class ServoWebDriverTestharnessExecutor(TestharnessExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 close_after_done=True, capabilities=None, debug_info=None):
+        TestharnessExecutor.__init__(self, browser, server_config, timeout_multiplier=1,
+                                     debug_info=None)
+        self.protocol = ServoWebDriverProtocol(self, browser, capabilities=capabilities)
+        with open(os.path.join(here, "testharness_servodriver.js")) as f:
+            self.script = f.read()
+        self.timeout = None
+
+    def on_protocol_change(self, new_protocol):
+        pass
+
+    def is_alive(self):
+        return self.protocol.is_alive()
+
+    def do_test(self, test):
+        url = self.test_url(test)
+
+        timeout = test.timeout * self.timeout_multiplier + extra_timeout
+
+        if timeout != self.timeout:
+            try:
+                self.protocol.session.timeouts.script = timeout
+                self.timeout = timeout
+            except IOError:
+                self.logger.error("Lost webdriver connection")
+                return Stop
+
+        success, data = ServoWebDriverRun(self.do_testharness,
+                                          self.protocol.session,
+                                          url,
+                                          timeout).run()
+
+        if success:
+            return self.convert_result(test, data)
+
+        return (test.result_cls(*data), [])
+
+    def do_testharness(self, session, url, timeout):
+        session.url = url
+        result = json.loads(
+            session.execute_async_script(
+                self.script % {"abs_url": url,
+                               "url": strip_server(url),
+                               "timeout_multiplier": self.timeout_multiplier,
+                               "timeout": timeout * 1000}))
+        # Prevent leaking every page in history until Servo develops a more sane
+        # page cache
+        session.back()
+        return result
+
+
+class TimeoutError(Exception):
+    pass
+
+
+class ServoWebDriverRefTestExecutor(RefTestExecutor):
+    def __init__(self, browser, server_config, timeout_multiplier=1,
+                 screenshot_cache=None, capabilities=None, debug_info=None):
+        """Selenium WebDriver-based executor for reftests"""
+        RefTestExecutor.__init__(self,
+                                 browser,
+                                 server_config,
+                                 screenshot_cache=screenshot_cache,
+                                 timeout_multiplier=timeout_multiplier,
+                                 debug_info=debug_info)
+        self.protocol = ServoWebDriverProtocol(self, browser,
+                                               capabilities=capabilities)
+        self.implementation = RefTestImplementation(self)
+        self.timeout = None
+        with open(os.path.join(here, "reftest-wait_servodriver.js")) as f:
+            self.wait_script = f.read()
+
+    def is_alive(self):
+        return self.protocol.is_alive()
+
+    def do_test(self, test):
+        try:
+            result = self.implementation.run_test(test)
+            return self.convert_result(test, result)
+        except IOError:
+            return test.result_cls("CRASH", None), []
+        except TimeoutError:
+            return test.result_cls("TIMEOUT", None), []
+        except Exception as e:
+            message = getattr(e, "message", "")
+            if message:
+                message += "\n"
+            message += traceback.format_exc(e)
+            return test.result_cls("ERROR", message), []
+
+    def screenshot(self, test, viewport_size, dpi):
+        # https://github.com/w3c/wptrunner/issues/166
+        assert viewport_size is None
+        assert dpi is None
+
+        timeout = (test.timeout * self.timeout_multiplier + extra_timeout
+                   if self.debug_info is None else None)
+
+        if self.timeout != timeout:
+            try:
+                self.protocol.session.timeouts.script = timeout
+                self.timeout = timeout
+            except IOError:
+                self.logger.error("Lost webdriver connection")
+                return Stop
+
+        return ServoWebDriverRun(self._screenshot,
+                                 self.protocol.session,
+                                 self.test_url(test),
+                                 timeout).run()
+
+    def _screenshot(self, session, url, timeout):
+        session.url = url
+        session.execute_async_script(self.wait_script)
+        return session.screenshot()
diff --git a/testing/web-platform/harness/wptrunner/executors/process.py b/testing/web-platform/harness/wptrunner/executors/process.py
new file mode 100644
index 000000000..45f33ab2c
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/process.py
@@ -0,0 +1,24 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from .base import TestExecutor
+
+
+class ProcessTestExecutor(TestExecutor):
+    def __init__(self, *args, **kwargs):
+        TestExecutor.__init__(self, *args, **kwargs)
+        self.binary = self.browser.binary
+        self.interactive = (False if self.debug_info is None
+                            else self.debug_info.interactive)
+
+    def setup(self, runner):
+        self.runner = runner
+        self.runner.send_message("init_succeeded")
+        return True
+
+    def is_alive(self):
+        return True
+
+    def do_test(self, test):
+        raise NotImplementedError
diff --git a/testing/web-platform/harness/wptrunner/executors/pytestrunner/__init__.py b/testing/web-platform/harness/wptrunner/executors/pytestrunner/__init__.py
new file mode 100644
index 000000000..de3a34a79
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/pytestrunner/__init__.py
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from . import fixtures
+from .runner import run
diff --git a/testing/web-platform/harness/wptrunner/executors/pytestrunner/fixtures.py b/testing/web-platform/harness/wptrunner/executors/pytestrunner/fixtures.py
new file mode 100644
index 000000000..1b4e8d43d
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/pytestrunner/fixtures.py
@@ -0,0 +1,76 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import pytest
+
+import urlparse
+
+
+"""pytest fixtures for use in Python-based WPT tests.
+
+The purpose of test fixtures is to provide a fixed baseline upon which
+tests can reliably and repeatedly execute.
+"""
+
+
+class Session(object):
+    """Fixture to allow access to wptrunner's existing WebDriver session
+    in tests.
+
+    The session is not created by default to enable testing of session
+    creation.  However, a module-scoped session will be implicitly created
+    at the first call to a WebDriver command.  This means methods such as
+    `session.send_command` and `session.session_id` are possible to use
+    without having a session.
+
+    To illustrate implicit session creation::
+
+        def test_session_scope(session):
+            # at this point there is no session
+            assert session.session_id is None
+
+            # window_id is a WebDriver command,
+            # and implicitly creates the session for us
+            assert session.window_id is not None
+
+            # we now have a session
+            assert session.session_id is not None
+
+    You can also access the session in custom fixtures defined in the
+    tests, such as a setup function::
+
+        @pytest.fixture(scope="function")
+        def setup(request, session):
+            session.url = "https://example.org"
+
+        def test_something(setup, session):
+            assert session.url == "https://example.org"
+
+    The session is closed when the test module goes out of scope by an
+    implicit call to `session.end`.
+    """
+
+    def __init__(self, client):
+        self.client = client
+
+    @pytest.fixture(scope="module")
+    def session(self, request):
+        request.addfinalizer(self.client.end)
+        return self.client
+
+class Server(object):
+    """Fixture to allow access to wptrunner's base server url.
+
+    :param url_getter: Function to get server url from test environment, given
+        a protocol.
+    """
+    def __init__(self, url_getter):
+        self.server_url = url_getter
+
+    def where_is(self, uri, protocol="http"):
+        return urlparse.urljoin(self.server_url(protocol), uri)
+
+    @pytest.fixture
+    def server(self, request):
+        return self
diff --git a/testing/web-platform/harness/wptrunner/executors/pytestrunner/runner.py b/testing/web-platform/harness/wptrunner/executors/pytestrunner/runner.py
new file mode 100644
index 000000000..28b8f609c
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/pytestrunner/runner.py
@@ -0,0 +1,116 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+"""Provides interface to deal with pytest.
+
+Usage::
+
+    session = webdriver.client.Session("127.0.0.1", "4444", "/")
+    harness_result = ("OK", None)
+    subtest_results = pytestrunner.run("/path/to/test", session.url)
+    return (harness_result, subtest_results)
+"""
+
+import errno
+import shutil
+import tempfile
+
+from . import fixtures
+
+
+pytest = None
+
+
+def do_delayed_imports():
+    global pytest
+    import pytest
+
+
+def run(path, session, url_getter, timeout=0):
+    """Run Python test at ``path`` in pytest.  The provided ``session``
+    is exposed as a fixture available in the scope of the test functions.
+
+    :param path: Path to the test file.
+    :param session: WebDriver session to expose.
+    :param url_getter: Function to get server url from test environment, given
+        a protocol.
+    :param timeout: Duration before interrupting potentially hanging
+        tests.  If 0, there is no timeout.
+
+    :returns: List of subtest results, which are tuples of (test id,
+        status, message, stacktrace).
+    """
+
+    if pytest is None:
+        do_delayed_imports()
+
+    recorder = SubtestResultRecorder()
+    plugins = [recorder,
+               fixtures.Session(session),
+               fixtures.Server(url_getter)]
+
+    # TODO(ato): Deal with timeouts
+
+    with TemporaryDirectory() as cache:
+        pytest.main(["--strict",  # turn warnings into errors
+                     "--verbose",  # show each individual subtest
+                     "--capture", "no",  # enable stdout/stderr from tests
+                     "--basetemp", cache,  # temporary directory
+                     path],
+                    plugins=plugins)
+
+    return recorder.results
+
+
+class SubtestResultRecorder(object):
+    def __init__(self):
+        self.results = []
+
+    def pytest_runtest_logreport(self, report):
+        if report.passed and report.when == "call":
+            self.record_pass(report)
+        elif report.failed:
+            if report.when != "call":
+                self.record_error(report)
+            else:
+                self.record_fail(report)
+        elif report.skipped:
+            self.record_skip(report)
+
+    def record_pass(self, report):
+        self.record(report.nodeid, "PASS")
+
+    def record_fail(self, report):
+        self.record(report.nodeid, "FAIL", stack=report.longrepr)
+
+    def record_error(self, report):
+        # error in setup/teardown
+        if report.when != "call":
+            message = "%s error" % report.when
+        self.record(report.nodeid, "ERROR", message, report.longrepr)
+
+    def record_skip(self, report):
+        self.record(report.nodeid, "ERROR",
+                    "In-test skip decorators are disallowed, "
+                    "please use WPT metadata to ignore tests.")
+
+    def record(self, test, status, message=None, stack=None):
+        if stack is not None:
+            stack = str(stack)
+        new_result = (test, status, message, stack)
+        self.results.append(new_result)
+
+
+class TemporaryDirectory(object):
+    def __enter__(self):
+        self.path = tempfile.mkdtemp(prefix="pytest-")
+        return self.path
+
+    def __exit__(self, *args):
+        try:
+            shutil.rmtree(self.path)
+        except OSError as e:
+            # no such file or directory
+            if e.errno != errno.ENOENT:
+                raise
diff --git a/testing/web-platform/harness/wptrunner/executors/reftest-wait.js b/testing/web-platform/harness/wptrunner/executors/reftest-wait.js
new file mode 100644
index 000000000..a2bc66565
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/reftest-wait.js
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function test(x) {
+  log("classList: " + root.classList);
+  if (!root.classList.contains("reftest-wait")) {
+    observer.disconnect();
+    marionetteScriptFinished();
+  }
+}
+
+var root = document.documentElement;
+var observer = new MutationObserver(test);
+
+observer.observe(root, {attributes: true});
+
+if (document.readyState != "complete") {
+  onload = test
+} else {
+  test();
+}
diff --git a/testing/web-platform/harness/wptrunner/executors/reftest-wait_servodriver.js b/testing/web-platform/harness/wptrunner/executors/reftest-wait_servodriver.js
new file mode 100644
index 000000000..6040b4336
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/reftest-wait_servodriver.js
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+callback = arguments[arguments.length - 1];
+
+function check_done() {
+    if (!document.body.classList.contains('reftest-wait')) {
+        callback();
+    } else {
+        setTimeout(check_done, 50);
+    }
+}
+
+if (document.readyState === 'complete') {
+    check_done();
+} else {
+    addEventListener("load", check_done);
+}
diff --git a/testing/web-platform/harness/wptrunner/executors/reftest-wait_webdriver.js b/testing/web-platform/harness/wptrunner/executors/reftest-wait_webdriver.js
new file mode 100644
index 000000000..187f5daac
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/reftest-wait_webdriver.js
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var callback = arguments[arguments.length - 1];
+
+function test(x) {
+  if (!root.classList.contains("reftest-wait")) {
+    observer.disconnect();
+    callback()
+  }
+}
+
+var root = document.documentElement;
+var observer = new MutationObserver(test);
+
+observer.observe(root, {attributes: true});
+
+if (document.readyState != "complete") {
+    onload = test;
+} else {
+    test();
+}
diff --git a/testing/web-platform/harness/wptrunner/executors/reftest.js b/testing/web-platform/harness/wptrunner/executors/reftest.js
new file mode 100644
index 000000000..3d7a9b6d2
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/reftest.js
@@ -0,0 +1,5 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var win = window.open("about:blank", "test", "width=600,height=600");
diff --git a/testing/web-platform/harness/wptrunner/executors/testharness_marionette.js b/testing/web-platform/harness/wptrunner/executors/testharness_marionette.js
new file mode 100644
index 000000000..0d0e4017a
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/testharness_marionette.js
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+window.wrappedJSObject.timeout_multiplier = %(timeout_multiplier)d;
+window.wrappedJSObject.explicit_timeout = %(explicit_timeout)d;
+
+window.wrappedJSObject.addEventListener("message", function listener(event) {
+    if (event.data.type != "complete") {
+        return;
+    }
+    window.wrappedJSObject.removeEventListener("message", listener);
+    clearTimeout(timer);
+    var tests = event.data.tests;
+    var status = event.data.status;
+
+    var subtest_results = tests.map(function (x) {
+        return [x.name, x.status, x.message, x.stack]
+    });
+
+    marionetteScriptFinished(["%(url)s",
+                              status.status,
+                              status.message,
+                              status.stack,
+                              subtest_results]);
+}, false);
+
+window.wrappedJSObject.win = window.open("%(abs_url)s", "%(window_id)s");
+
+var timer = null;
+if (%(timeout)s) {
+    timer = setTimeout(function() {
+        log("Timeout fired");
+        window.wrappedJSObject.win.timeout();
+    }, %(timeout)s);
+}
diff --git a/testing/web-platform/harness/wptrunner/executors/testharness_servodriver.js b/testing/web-platform/harness/wptrunner/executors/testharness_servodriver.js
new file mode 100644
index 000000000..20aeb34b9
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/testharness_servodriver.js
@@ -0,0 +1,6 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+window.__wd_results_callback__ = arguments[arguments.length - 1];
+window.__wd_results_timer__ = setTimeout(timeout, %(timeout)s);
diff --git a/testing/web-platform/harness/wptrunner/executors/testharness_webdriver.js b/testing/web-platform/harness/wptrunner/executors/testharness_webdriver.js
new file mode 100644
index 000000000..7ca8d5737
--- /dev/null
+++ b/testing/web-platform/harness/wptrunner/executors/testharness_webdriver.js
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var callback = arguments[arguments.length - 1];
+window.timeout_multiplier = %(timeout_multiplier)d;
+
+window.addEventListener("message", function(event) {
+  var tests = event.data[0];
+  var status = event.data[1];
+
+  var subtest_results = tests.map(function(x) {
+      return [x.name, x.status, x.message, x.stack]
+  });
+
+  clearTimeout(timer);
+  callback(["%(url)s",
+            status.status,
+            status.message,
+            status.stack,
+            subtest_results]);
+}, false);
+
+window.win = window.open("%(abs_url)s", "%(window_id)s");
+
+var timer = setTimeout(function() {
+  window.win.timeout();
+  window.win.close();
+}, %(timeout)s);