--- a/npm-shrinkwrap.json
+++ b/npm-shrinkwrap.json
@@ -1577,9 +1577,9 @@
       "integrity": "sha1-pcbVMr5lbiPbgg77lDofBJmNY68="
     },
     "yallist": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-2.1.2.tgz",
       "integrity": "sha1-HBH5IY8HYImkfdUS+TxmmaaoHVI="
     }
   }
-}
+}
\ No newline at end of file

--- a/testing/marionette/client/docs/conf.py
+++ b/testing/marionette/client/docs/conf.py
@@ -6,16 +6,18 @@
 # This file is execfile()d with the current directory set to its containing dir.
 #
 # Note that not all possible configuration values are present in this
 # autogenerated file.
 #
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
+from __future__ import absolute_import
+
 import os
 import sys
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 # sys.path.insert(0, os.path.abspath('.'))
 

--- a/testing/marionette/client/marionette_driver/__init__.py
+++ b/testing/marionette/client/marionette_driver/__init__.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 __version__ = '2.5.0'
 
 from marionette_driver import (
     addons,
     by,
     date_time_value,
     decorators,
     errors,

--- a/testing/marionette/client/marionette_driver/addons.py
+++ b/testing/marionette/client/marionette_driver/addons.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from . import errors
 
 __all__ = ["Addons", "AddonInstallException"]
 
 
 class AddonInstallException(errors.MarionetteException):
     pass
 

--- a/testing/marionette/client/marionette_driver/by.py
+++ b/testing/marionette/client/marionette_driver/by.py
@@ -8,16 +8,18 @@
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import
+
 
 class By(object):
     ID = "id"
     XPATH = "xpath"
     LINK_TEXT = "link text"
     PARTIAL_LINK_TEXT = "partial link text"
     NAME = "name"
     TAG_NAME = "tag name"

--- a/testing/marionette/client/marionette_driver/date_time_value.py
+++ b/testing/marionette/client/marionette_driver/date_time_value.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 
 class DateTimeValue(object):
     """
     Interface for setting the value of HTML5 "date" and "time" input elements.
 
     Simple usage example:
 
     ::

--- a/testing/marionette/client/marionette_driver/decorators.py
+++ b/testing/marionette/client/marionette_driver/decorators.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import,
+    print_function
+)
+
 from functools import wraps
 import socket
 
 
 def _find_marionette_in_args(*args, **kwargs):
     try:
         m = [a for a in args + tuple(kwargs.values()) if hasattr(a, 'session')][0]
     except IndexError:

--- a/testing/marionette/client/marionette_driver/errors.py
+++ b/testing/marionette/client/marionette_driver/errors.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import traceback
 
 
 class MarionetteException(Exception):
 
     """Raised when a generic non-recoverable exception has occured."""
 
     status = "webdriver error"

--- a/testing/marionette/client/marionette_driver/expected.py
+++ b/testing/marionette/client/marionette_driver/expected.py
@@ -1,16 +1,18 @@
 # 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 errors
+from __future__ import absolute_import
+
 import types
+from . import errors
 
-from marionette import HTMLElement
+from .marionette import HTMLElement
 
 """This file provides a set of expected conditions for common use
 cases when writing Marionette tests.
 
 The conditions rely on explicit waits that retries conditions a number
 of times until they are either successfully met, or they time out.
 
 """

--- a/testing/marionette/client/marionette_driver/geckoinstance.py
+++ b/testing/marionette/client/marionette_driver/geckoinstance.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 import sys
 import tempfile
 import time
 
 from copy import deepcopy
 
 import mozversion
@@ -204,17 +206,17 @@ class GeckoInstance(object):
             if not app and kwargs["bin"] is not None:
                 app_id = mozversion.get_version(binary=kwargs["bin"])["application_id"]
                 app = app_ids[app_id]
 
             instance_class = apps[app]
         except (IOError, KeyError):
             exc, val, tb = sys.exc_info()
             msg = 'Application "{0}" unknown (should be one of {1})'
-            raise NotImplementedError, msg.format(app, apps.keys()), tb
+            raise NotImplementedError(msg.format(app, apps.keys()), tb)
 
         return instance_class(*args, **kwargs)
 
     def start(self):
         self._update_profile()
         self.runner = self.runner_class(**self._get_runner_args())
         self.runner.start()
 
@@ -347,17 +349,17 @@ class FennecInstance(GeckoInstance):
         self.runner = self.runner_class(**self._get_runner_args())
         try:
             if self.connect_to_running_emulator:
                 self.runner.device.connect()
             self.runner.start()
         except Exception as e:
             exc, val, tb = sys.exc_info()
             message = "Error possibly due to runner or device args: {}"
-            raise exc, message.format(e.message), tb
+            raise exc(message.format(e.message), tb)
         # gecko_log comes from logcat when running with device/emulator
         logcat_args = {
             "filterspec": "Gecko",
             "serial": self.runner.device.dm._deviceSerial
         }
         if self.gecko_log == "-":
             logcat_args["stream"] = sys.stdout
         else:

--- a/testing/marionette/client/marionette_driver/gestures.py
+++ b/testing/marionette/client/marionette_driver/gestures.py
@@ -1,13 +1,15 @@
 # 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 marionette import MultiActions, Actions
+from __future__ import absolute_import
+
+from .marionette import MultiActions, Actions
 
 
 def smooth_scroll(marionette_session, start_element, axis, direction,
                   length, increments=None, wait_period=None, scroll_back=None):
     """
         :param axis:  y or x
         :param direction: 0 for positive, and -1 for negative
         :param length: total length of scroll scroll

--- a/testing/marionette/client/marionette_driver/keys.py
+++ b/testing/marionette/client/marionette_driver/keys.py
@@ -8,16 +8,18 @@
 #     http //www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing software
 # distributed under the License is distributed on an "AS IS" BASIS
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import
+
 
 class Keys(object):
 
     NULL = u'\ue000'
     CANCEL = u'\ue001'  # ^break
     HELP = u'\ue002'
     BACK_SPACE = u'\ue003'
     TAB = u'\ue004'

--- a/testing/marionette/client/marionette_driver/localization.py
+++ b/testing/marionette/client/marionette_driver/localization.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 
 class L10n(object):
     """An API which allows Marionette to handle localized content.
 
     The `localization`_ of UI elements in Gecko based applications is done via
     entities and properties. For static values entities are used, which are located
     in .dtd files. Whereby for dynamically updated content the values come from
     .property files. Both types of elements can be identifed via a unique id,

--- a/testing/marionette/client/marionette_driver/marionette.py
+++ b/testing/marionette/client/marionette_driver/marionette.py
@@ -1,26 +1,28 @@
 # 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 __future__ import absolute_import
+
 import base64
 import datetime
 import json
 import os
 import socket
 import sys
 import time
 import traceback
 import warnings
 
 from contextlib import contextmanager
 
-import errors
-import transport
+from . import errors
+from . import transport
 
 from .decorators import do_process_check
 from .geckoinstance import GeckoInstance
 from .keys import Keys
 from .timeout import Timeouts
 
 WEBELEMENT_KEY = "ELEMENT"
 W3C_WEBELEMENT_KEY = "element-6066-11e4-a52e-4f735466cecf"
@@ -634,17 +636,17 @@ class Marionette(object):
         except socket.timeout:
             # Something went wrong with starting up Marionette server. Given
             # that the process will not quit itself, force a shutdown immediately.
             self.cleanup()
 
             msg = "Process killed after {}s because no connection to Marionette "\
                   "server could be established. Check gecko.log for errors"
             _, _, tb = sys.exc_info()
-            raise IOError, msg.format(timeout), tb
+            raise IOError(msg.format(timeout), tb)
 
     def cleanup(self):
         if self.session is not None:
             try:
                 self.delete_session()
             except (errors.MarionetteException, IOError):
                 # These exceptions get thrown if the Marionette server
                 # hit an exception/died or the connection died. We can
@@ -788,17 +790,17 @@ class Marionette(object):
         frame, and is only called via the `@do_process_check` decorator.
 
         """
         exc, val, tb = sys.exc_info()
 
         # If the application hasn't been launched by Marionette no further action can be done.
         # In such cases we simply re-throw the exception.
         if not self.instance:
-            raise exc, val, tb
+            raise exc(val, tb)
 
         else:
             # Somehow the socket disconnected. Give the application some time to shutdown
             # itself before killing the process.
             returncode = self.instance.runner.wait(timeout=self.DEFAULT_SHUTDOWN_TIMEOUT)
 
             if returncode is None:
                 message = ('Process killed because the connection to Marionette server is '
@@ -816,17 +818,17 @@ class Marionette(object):
                         message = 'Process crashed (Exit code: {returncode})'
                 else:
                     message = 'Process has been unexpectedly closed (Exit code: {returncode})'
 
                 self.delete_session(send_request=False, reset_session_id=True)
 
             message += ' (Reason: {reason})'
 
-            raise IOError, message.format(returncode=returncode, reason=val), tb
+            raise IOError(message.format(returncode=returncode, reason=val), tb)
 
     @staticmethod
     def convert_keys(*string):
         typing = []
         for val in string:
             if isinstance(val, Keys):
                 typing.append(val)
             elif isinstance(val, int):
@@ -1146,17 +1148,17 @@ class Marionette(object):
 
             try:
                 timeout = self.DEFAULT_SHUTDOWN_TIMEOUT + self.DEFAULT_STARTUP_TIMEOUT
                 self.raise_for_port(timeout=timeout)
             except socket.timeout:
                 if self.instance.runner.returncode is not None:
                     exc, val, tb = sys.exc_info()
                     self.cleanup()
-                    raise exc, "Requested restart of the application was aborted", tb
+                    raise exc("Requested restart of the application was aborted", tb)
 
         else:
             self.delete_session()
             self.instance.restart(clean=clean)
             self.raise_for_port(timeout=self.DEFAULT_STARTUP_TIMEOUT)
 
         if cause not in (None, "restart"):
             raise errors.MarionetteException("Unexpected shutdown reason '{}' for "

--- a/testing/marionette/client/marionette_driver/selection.py
+++ b/testing/marionette/client/marionette_driver/selection.py
@@ -1,13 +1,15 @@
 # -*- coding: utf-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 __future__ import absolute_import
+
 
 class SelectionManager(object):
     '''Interface for manipulating the selection and carets of the element.
 
     We call the blinking cursor (nsCaret) as cursor, and call AccessibleCaret as
     caret for short.
 
     Simple usage example:

--- a/testing/marionette/client/marionette_driver/timeout.py
+++ b/testing/marionette/client/marionette_driver/timeout.py
@@ -1,14 +1,16 @@
 # 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 errors
+from __future__ import absolute_import
+
+from . import errors
 
 
 DEFAULT_SCRIPT_TIMEOUT = 30
 DEFAULT_PAGE_LOAD_TIMEOUT = 300
 DEFAULT_IMPLICIT_WAIT_TIMEOUT = 0
 
 
 class Timeouts(object):

--- a/testing/marionette/client/marionette_driver/transport.py
+++ b/testing/marionette/client/marionette_driver/transport.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import json
 import socket
 import sys
 import time
 
 
 class SocketTimeout(object):
     def __init__(self, socket, timeout):
@@ -199,17 +201,17 @@ class TcpTransport(object):
             with SocketTimeout(self._sock, 60.0):
                 # first packet is always a JSON Object
                 # which we can use to tell which protocol level we are at
                 raw = self.receive(unmarshal=False)
         except socket.timeout:
             msg = "Connection attempt failed because no data has been received over the socket: {}"
             exc, val, tb = sys.exc_info()
 
-            raise exc, msg.format(val), tb
+            raise exc(msg.format(val), tb)
 
         hello = json.loads(raw)
         application_type = hello.get("applicationType")
         protocol = hello.get("marionetteProtocol")
 
         if application_type != "gecko":
             raise ValueError("Application type '{}' is not supported".format(application_type))
 

--- a/testing/marionette/client/marionette_driver/wait.py
+++ b/testing/marionette/client/marionette_driver/wait.py
@@ -1,14 +1,16 @@
 # 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 __future__ import absolute_import
+
 import collections
-import errors
+from . import errors
 import sys
 import time
 
 DEFAULT_TIMEOUT = 5
 DEFAULT_INTERVAL = 0.1
 
 
 class Wait(object):

--- a/testing/marionette/client/setup.py
+++ b/testing/marionette/client/setup.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 import re
 from setuptools import setup, find_packages
 
 THIS_DIR = os.path.dirname(os.path.realpath(__name__))
 
 
 def read(*parts):

--- a/testing/marionette/harness/marionette_harness/__init__.py
+++ b/testing/marionette/harness/marionette_harness/__init__.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 __version__ = '4.3.0'
 
 from .marionette_test import (
     CommonTestCase,
     expectedFailure,
     MarionetteTestCase,
     parameterized,
     run_if_e10s,

--- a/testing/marionette/harness/marionette_harness/marionette_test/__init__.py
+++ b/testing/marionette/harness/marionette_harness/marionette_test/__init__.py
@@ -1,15 +1,16 @@
 # 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 __future__ import absolute_import
+
 __version__ = '3.1.0'
 
-
 from unittest.case import (
     expectedFailure,
     skip,
     SkipTest,
 )
 
 from .decorators import (
     parameterized,

--- a/testing/marionette/harness/marionette_harness/marionette_test/decorators.py
+++ b/testing/marionette/harness/marionette_harness/marionette_test/decorators.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import functools
 import types
 
 from unittest.case import (
     SkipTest,
 )
 
 

--- a/testing/marionette/harness/marionette_harness/marionette_test/testcases.py
+++ b/testing/marionette/harness/marionette_harness/marionette_test/testcases.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import imp
 import re
 import sys
 import time
 import types
 import unittest
 import warnings
 import weakref

--- a/testing/marionette/harness/marionette_harness/runner/__init__.py
+++ b/testing/marionette/harness/marionette_harness/runner/__init__.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from .base import (
     BaseMarionetteArguments,
     BaseMarionetteTestRunner,
     Marionette,
     MarionetteTest,
     MarionetteTestResult,
     MarionetteTextTestRunner,
     TestManifest,

--- a/testing/marionette/harness/marionette_harness/runner/base.py
+++ b/testing/marionette/harness/marionette_harness/runner/base.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import json
 import os
 import random
 import re
 import socket
 import sys
 import time
 import traceback
@@ -15,24 +17,24 @@ import unittest
 from argparse import ArgumentParser
 from collections import defaultdict
 from copy import deepcopy
 
 import mozinfo
 import moznetwork
 import mozprofile
 import mozversion
-import serve
+from . import serve
 
 from manifestparser import TestManifest
 from manifestparser.filters import tags
 from marionette_driver.marionette import Marionette
 from moztest.adapters.unit import StructuredTestResult, StructuredTestRunner
 from moztest.results import TestResult, TestResultCollection, relevant_line
-from serve import iter_proc, iter_url
+from .serve import iter_proc, iter_url
 
 here = os.path.abspath(os.path.dirname(__file__))
 
 
 def update_mozinfo(path=None):
     """Walk up directories to find mozinfo.json and update the info."""
     path = path or here
     dirs = set()
@@ -651,17 +653,17 @@ class BaseMarionetteTestRunner(object):
                 if not os.path.exists(path):
                     raise IOError('--testvars file {} does not exist'.format(path))
                 try:
                     with open(path) as f:
                         data.append(json.loads(f.read()))
                 except ValueError as e:
                     exc, val, tb = sys.exc_info()
                     msg = "JSON file ({0}) is not properly formatted: {1}"
-                    raise exc, msg.format(os.path.abspath(path), e.message), tb
+                    raise exc(msg.format(os.path.abspath(path), e.message), tb)
         return data
 
     @property
     def capabilities(self):
         if self._capabilities:
             return self._capabilities
 
         self.marionette.start_session()
@@ -762,17 +764,17 @@ class BaseMarionetteTestRunner(object):
                 try:
                     # Establish a socket connection so we can vertify the data come back
                     connection = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                     connection.connect((host, int(port)))
                     connection.close()
                 except Exception as e:
                     exc, val, tb = sys.exc_info()
                     msg = "Connection attempt to {0}:{1} failed with error: {2}"
-                    raise exc, msg.format(host, port, e), tb
+                    raise exc(msg.format(host, port, e), tb)
         if self.workspace:
             kwargs['workspace'] = self.workspace_path
         if self.headless:
             kwargs['headless'] = True
 
         return kwargs
 
     def record_crash(self):
@@ -912,17 +914,17 @@ class BaseMarionetteTestRunner(object):
             # raise only the exception if we were not interrupted
             if not interrupted:
                 raise
         finally:
             self.cleanup()
 
             # reraise previous interruption now
             if interrupted:
-                raise interrupted[0], interrupted[1], interrupted[2]
+                raise interrupted[0](interrupted[1], interrupted[2])
 
     def _print_summary(self, tests):
         self.logger.info('\nSUMMARY\n-------')
         self.logger.info('passed: {}'.format(self.passed))
         if self.unexpected_successes == 0:
             self.logger.info('failed: {}'.format(self.failed))
         else:
             self.logger.info(

--- a/testing/marionette/harness/marionette_harness/runner/httpd.py
+++ b/testing/marionette/harness/marionette_harness/runner/httpd.py
@@ -3,16 +3,20 @@
 # 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/.
 
 """Specialisation of wptserver.server.WebTestHttpd for testing
 Marionette.
 
 """
+from __future__ import (
+    absolute_import,
+    print_function
+)
 
 import argparse
 import os
 import select
 import sys
 import time
 import urlparse
 
@@ -170,11 +174,13 @@ e.g. \"https://0.0.0.0:0/base/\"""")
         "-k", dest="ssl_key", default=default_ssl_key,
         help="path to SSL certificate key (default %(default)s)")
     args = parser.parse_args()
 
     httpd = FixtureServer(args.doc_root, args.url,
                           ssl_cert=args.ssl_cert,
                           ssl_key=args.ssl_key)
     httpd.start()
-    print >>sys.stderr, "%s: started fixture server on %s" % \
-        (sys.argv[0], httpd.get_url("/"))
+    print(
+        sys.stderr,
+        "%s: started fixture server on %s" % (sys.argv[0], httpd.get_url("/"))
+        )
     httpd.wait()

--- a/testing/marionette/harness/marionette_harness/runner/mixins/__init__.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/__init__.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from .browsermob import (
     BrowserMobProxyTestCaseMixin,
     BrowserMobProxyArguments,
     BrowserMobTestCase,
 )
 
 from .window_manager import (
     WindowManagerMixin,

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/__init__.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/__init__.py
@@ -1,6 +1,8 @@
+from __future__ import absolute_import
+
 __version__ = '0.5.0'
 
 from .server import Server
 from .client import Client
 
 __all__ = ['Server', 'Client', 'browsermobproxy']

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/client.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/client.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import requests
 
 try:
   from urllib.parse import urlencode, unquote
 except ImportError:
   from urllib import urlencode, unquote
 import json
 

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/server.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/server.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import os
 import platform
 import socket
 import subprocess
 import time
 
 from .client import Client
 

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/webdriver_event_listener.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/browsermobproxy/webdriver_event_listener.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from selenium.webdriver.support.abstract_event_listener import AbstractEventListener
 
 class WebDriverEventListener(AbstractEventListener):
 
     def __init__(self, client, refs={}):
         self.client = client
         self.hars = []
         self.refs = refs

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/docs/conf.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/docs/conf.py
@@ -6,16 +6,18 @@
 # This file is execfile()d with the current directory set to its containing dir.
 #
 # Note that not all possible configuration values are present in this
 # autogenerated file.
 #
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
+from __future__ import absolute_import
+
 import sys, os
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 sys.path.insert(0, os.path.abspath('../'))
 
 # -- General configuration -----------------------------------------------------

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/setup.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/setup.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from setuptools import setup, find_packages
 
 setup(name='browsermob-proxy',
       version='0.6.0',
       description='A library for interacting with the Browsermob Proxy',
       author='David Burns',
       author_email='david.burns at theautomatedtester dot co dot uk',
       url='http://oss.theautomatedtester.co.uk/browsermob-proxy-py',

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_client.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_client.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import os.path
 import pytest
 import sys
 
 
 def setup_module(module):
     sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
 

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_remote.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_remote.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from selenium import webdriver
 import selenium.webdriver.common.desired_capabilities
 import os
 import sys
 import time
 import pytest
 
 def setup_module(module):

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_webdriver.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob-proxy-py/test/test_webdriver.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from selenium import webdriver
 import selenium.webdriver.common.desired_capabilities
 from selenium.webdriver.common.proxy import Proxy
 import os
 import sys
 import copy
 import time
 import pytest

--- a/testing/marionette/harness/marionette_harness/runner/mixins/browsermob.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/browsermob.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 
 from browsermobproxy import Server
 from marionette_harness import MarionetteTestCase
 
 
 class BrowserMobProxyArguments(object):
     name = 'Browsermob Proxy'

--- a/testing/marionette/harness/marionette_harness/runner/mixins/window_manager.py
+++ b/testing/marionette/harness/marionette_harness/runner/mixins/window_manager.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import sys
 
 from marionette_driver import By, Wait
 
 
 class WindowManagerMixin(object):
 
     _menu_item_new_tab = (By.ID, "menu_newNavigatorTab")
@@ -63,17 +65,17 @@ class WindowManagerMixin(object):
         try:
             if callable(trigger):
                 trigger()
             elif trigger == 'menu':
                 with self.marionette.using_context("chrome"):
                     self.marionette.find_element(*self._menu_item_new_tab).click()
         except Exception:
             exc, val, tb = sys.exc_info()
-            raise exc, 'Failed to trigger opening a new tab: {}'.format(val), tb
+            raise exc('Failed to trigger opening a new tab: {}'.format(val), tb)
         else:
             Wait(self.marionette).until(
                 lambda mn: len(mn.window_handles) == len(current_tabs) + 1,
                 message="No new tab has been opened"
             )
 
             [new_tab] = list(set(self.marionette.window_handles) - set(current_tabs))
 
@@ -94,17 +96,17 @@ class WindowManagerMixin(object):
         try:
             if callable(trigger):
                 trigger()
             else:
                 with self.marionette.using_context("chrome"):
                     self.marionette.execute_script("window.open();")
         except Exception:
             exc, val, tb = sys.exc_info()
-            raise exc, 'Failed to trigger opening a new window: {}'.format(val), tb
+            raise exc('Failed to trigger opening a new window: {}'.format(val), tb)
         else:
             Wait(self.marionette).until(
                 lambda mn: len(mn.chrome_window_handles) == len(current_windows) + 1,
                 message="No new window has been opened"
             )
 
             [new_window] = list(set(self.marionette.chrome_window_handles) - set(current_windows))
 

--- a/testing/marionette/harness/marionette_harness/runner/serve.py
+++ b/testing/marionette/harness/marionette_harness/runner/serve.py
@@ -4,24 +4,29 @@
 # 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/.
 
 """Spawns necessary HTTP servers for testing Marionette in child
 processes.
 
 """
 
+from __future__ import (
+    absolute_import,
+    print_function
+)
+
 import argparse
 import multiprocessing
 import os
 import sys
 
 from collections import defaultdict
 
-import httpd
+from . import httpd
 
 
 __all__ = ["default_doc_root",
            "iter_proc",
            "iter_url",
            "registered_servers",
            "servers",
            "start",
@@ -207,17 +212,17 @@ def main(args):
 
     parser = argparse.ArgumentParser()
     parser.add_argument("-r", dest="doc_root",
                         help="Path to document root.  Overrides default.")
     args = parser.parse_args()
 
     servers = start(args.doc_root)
     for url in iter_url(servers):
-        print >>sys.stderr, "{}: listening on {}".format(sys.argv[0], url)
+        print(sys.stderr, "{}: listening on {}".format(sys.argv[0], url))
 
     try:
         while any(proc.is_alive for proc in iter_proc(servers)):
             for proc in iter_proc(servers):
                 proc.proc.join(1)
     except KeyboardInterrupt:
         for proc in iter_proc(servers):
             proc.kill()

--- a/testing/marionette/harness/marionette_harness/runtests.py
+++ b/testing/marionette/harness/marionette_harness/runtests.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import sys
 
 import mozlog
 
 from marionette_driver import __version__ as driver_version
 
 from marionette_harness import (
     __version__,

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/conftest.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/conftest.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import pytest
 
 from mock import Mock, MagicMock
 
 from marionette_driver.marionette import Marionette
 
 from marionette_harness.runner.httpd import FixtureServer
 

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_httpd.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_httpd.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import json
 import os
 import types
 import urllib2
 
 import mozunit
 import pytest
 

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_arguments.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_arguments.py
@@ -1,11 +1,14 @@
 # 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 __future__ import absolute_import
+
 import mozunit
 import pytest
 
 from marionette_harness.runtests import MarionetteArguments
 
 
 @pytest.mark.parametrize("socket_timeout", ['A', '10', '1B-', '1C2', '44.35'])
 def test_parse_arg_socket_timeout(socket_timeout):

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_harness.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_harness.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import mozunit
 import pytest
 
 from mock import Mock, patch, sentinel
 
 import marionette_harness.marionette_test as marionette_test
 
 from marionette_harness.runtests import MarionetteTestRunner, MarionetteHarness, cli

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_runner.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_runner.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import manifestparser
 import mozunit
 import pytest
 
 from mock import Mock, patch, mock_open, sentinel, DEFAULT
 
 from marionette_harness.runtests import MarionetteTestRunner
 

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_test_result.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_marionette_test_result.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import mozunit
 import pytest
 
 from marionette_harness import MarionetteTestResult
 
 
 @pytest.fixture
 def empty_marionette_testcase():

--- a/testing/marionette/harness/marionette_harness/tests/harness_unit/test_serve.py
+++ b/testing/marionette/harness/marionette_harness/tests/harness_unit/test_serve.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import types
 
 import mozunit
 import pytest
 
 from marionette_harness.runner import serve
 from marionette_harness.runner.serve import iter_proc, iter_url
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/single_finger_functions.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/single_finger_functions.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from marionette_driver.marionette import Actions
 from marionette_driver.errors import TimeoutException
 from marionette_driver.by import By
 
 
 def wait_for_condition_else_raise(marionette, wait_for_condition, expected, script):
     try:
         wait_for_condition(lambda m: expected in m.execute_script(script))

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_accessibility.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_accessibility.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import sys
 import unittest
 
 from marionette_driver.by import By
 from marionette_driver.errors import (
     ElementNotAccessibleException,
     ElementNotInteractableException,
     ElementClickInterceptedException,

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_addons.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_addons.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 
 from marionette_driver.addons import Addons, AddonInstallException
 from marionette_harness import MarionetteTestCase
 
 
 here = os.path.abspath(os.path.dirname(__file__))
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_anonymous_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_anonymous_content.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import NoSuchElementException
 from marionette_driver.marionette import HTMLElement
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestAnonymousNodes(WindowManagerMixin, MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_browsermobproxy.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_browsermobproxy.py
@@ -1,10 +1,12 @@
 import datetime
 
+from __future__ import absolute_import
+
 from marionette_harness.runner import BrowserMobTestCase
 
 
 class TestBrowserMobProxy(BrowserMobTestCase):
     """To run this test, you'll need to download the browsermob-proxy from
        http://bmp.lightbody.net/, and then pass the path to the startup
        script (typically /path/to/browsermob-proxy-2.0.0/bin/browsermob-proxy)
        as the --browsermob-script argument when running runtests.py.

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_capabilities.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_capabilities.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import,
+    print_function
+)
+
 from marionette_driver.errors import SessionNotCreatedException
 
 from marionette_harness import MarionetteTestCase
 
 # Unlike python 3, python 2 doesn't have a proper implementation of realpath or
 # samefile for Windows. However this function, which does exactly what we want,
 # was added to python 2 to fix an issue with tcl installations and symlinks.
 from FixTk import convert_path

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_checkbox.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_checkbox.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestCheckbox(MarionetteTestCase):
     def test_selected(self):
         test_html = self.marionette.absolute_url("test.html")

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_checkbox_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_checkbox_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestSelectedChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_chrome.py
@@ -8,16 +8,18 @@
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 #Unless required by applicable law or agreed to in writing, software
 #distributed under the License is distributed on an "AS IS" BASIS,
 #WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #See the License for the specific language governing permissions and
 #limitations under the License.
 
+from __future__ import absolute_import
+
 from marionette_driver import By
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class ChromeTests(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_chrome_element_css.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_chrome_element_css.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestChromeElementCSS(MarionetteTestCase):
 
     def get_element_computed_style(self, element, property):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_clearing.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_clearing.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import InvalidElementStateException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestClear(MarionetteTestCase):
     def testWriteableTextInputShouldClear(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_cli_arguments.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_cli_arguments.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import copy
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestCommandLineArguments(MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_click.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_click.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver import By, errors
 
 from marionette_harness import (
     MarionetteTestCase,
     run_if_e10s,
     skip_if_mobile,

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_click_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_click_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestClickChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_click_scrolling.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_click_scrolling.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import MoveTargetOutOfBoundsException
 
 from marionette_harness import MarionetteTestCase, skip, skip_if_mobile
 
 
 class TestClickScrolling(MarionetteTestCase):
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_cookies.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_cookies.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 import calendar
 import random
 import time
 
 from marionette_driver.errors import UnsupportedOperationException
 from marionette_harness import MarionetteTestCase
 
 
@@ -46,17 +51,17 @@ class CookieTest(MarionetteTestCase):
             self.assertRaises(UnsupportedOperationException,
                               self.marionette.delete_all_cookies)
             self.assertRaises(UnsupportedOperationException,
                               self.marionette.get_cookies)
 
     def test_delete_all_cookie(self):
         self.marionette.add_cookie(self.COOKIE_A)
         cookie_returned = str(self.marionette.execute_script("return document.cookie"))
-        print cookie_returned
+        print(cookie_returned)
         self.assertTrue(self.COOKIE_A["name"] in cookie_returned)
         self.marionette.delete_all_cookies()
         self.assertFalse(self.marionette.get_cookies())
 
     def test_delete_cookie(self):
         self.marionette.add_cookie(self.COOKIE_A)
         cookie_returned = str(self.marionette.execute_script("return document.cookie"))
         self.assertTrue(self.COOKIE_A["name"] in cookie_returned)

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_crash.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_crash.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import glob
 import shutil
 
 from marionette_driver import Wait
 from marionette_driver.errors import (
     MarionetteException,
     NoSuchWindowException,
     TimeoutException

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_data_driven.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_data_driven.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness.marionette_test import (
     parameterized,
     with_parameters,
     MetaParameterized,
     MarionetteTestCase
 )
 
 class Parameterizable(object):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_date_time_value.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_date_time_value.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from datetime import datetime
 
 from marionette_driver.by import By
 from marionette_driver.date_time_value import DateTimeValue
 from marionette_harness import MarionetteTestCase
 
 
 class TestDateTime(MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_element_retrieval.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_element_retrieval.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import re
 import urllib
 
 from marionette_driver.by import By
 from marionette_driver.errors import NoSuchElementException, InvalidSelectorException
 from marionette_driver.marionette import HTMLElement
 
 from marionette_harness import MarionetteTestCase, skip

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_element_state.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_element_state.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 import types
 import urllib
 
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_element_state_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_element_state_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase, skip, WindowManagerMixin
 
 
 class TestElementState(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_elementsize.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_elementsize.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestElementSize(MarionetteTestCase):
     def testShouldReturnTheSizeOfALink(self):
         test_html = self.marionette.absolute_url("testSize.html")

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_elementsize_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_elementsize_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestElementSizeChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_errors.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_errors.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import sys
 
 from marionette_driver import errors
 
 from marionette_harness import marionette_test
 
 
 def fake_cause():

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_execute_async_script.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_execute_async_script.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 from marionette_driver.errors import (
     JavascriptException,
     ScriptTimeoutException,
 )
 
 from marionette_harness import MarionetteTestCase
 
 
@@ -55,17 +57,17 @@ class TestExecuteAsyncContent(Marionette
 
     def test_execute_js_exception(self):
         try:
             self.marionette.execute_async_script("""
                 let a = 1;
                 foo(bar);
                 """)
             self.assertFalse(True)
-        except JavascriptException, inst:
+        except JavascriptException as inst:
             self.assertTrue('foo(bar)' in inst.stacktrace)
 
     def test_execute_async_js_exception(self):
         self.assertRaises(JavascriptException,
             self.marionette.execute_async_script, """
             var callback = arguments[arguments.length - 1];
             callback(foo());
             """)

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_execute_isolate.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_execute_isolate.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import ScriptTimeoutException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestExecuteIsolationContent(MarionetteTestCase):
     def setUp(self):
         super(TestExecuteIsolationContent, self).setUp()

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_execute_sandboxes.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_execute_sandboxes.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import JavascriptException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestExecuteSandboxes(MarionetteTestCase):
     def setUp(self):
         super(TestExecuteSandboxes, self).setUp()

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_execute_script.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_execute_script.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import os
 import urllib
 
 from marionette_driver import By, errors
 from marionette_driver.marionette import Alert, HTMLElement
 from marionette_driver.wait import Wait
 
 from marionette_harness import MarionetteTestCase, skip_if_mobile, WindowManagerMixin

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_expected.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_expected.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver import expected
 from marionette_driver.by import By
 
 from marionette_harness import marionette_test
 
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_expectedfail.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_expectedfail.py
@@ -1,11 +1,13 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestFail(MarionetteTestCase):
     def test_fails(self):
         # this test is supposed to fail!
         self.assertEquals(True, False)

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_file_upload.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_file_upload.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import contextlib
 import urllib
 
 from tempfile import NamedTemporaryFile as tempfile
 
 from marionette_driver import By, errors, expected
 from marionette_driver.wait import Wait
 from marionette_harness import MarionetteTestCase, skip

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_findelement_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_findelement_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import NoSuchElementException
 from marionette_driver.marionette import HTMLElement
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestElementsChrome(WindowManagerMixin, MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_geckoinstance.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_geckoinstance.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.geckoinstance import apps, GeckoInstance
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestGeckoInstance(MarionetteTestCase):
 
     def test_create(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_get_current_url_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_get_current_url_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import NoSuchWindowException
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin, skip_if_mobile
 
 
 class TestGetCurrentUrlChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_getactiveframe_oop.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_getactiveframe_oop.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 OOP_BY_DEFAULT = "dom.ipc.browser_frames.oop_by_default"
 BROWSER_FRAMES_ENABLED = "dom.mozBrowserFramesEnabeld"
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_implicit_waits.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_implicit_waits.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import NoSuchElementException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestImplicitWaits(MarionetteTestCase):
     def test_implicitly_wait_for_single_element(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_key_actions.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_key_actions.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 from marionette_driver.keys import Keys
 from marionette_driver.marionette import Actions
 
 from marionette_harness import MarionetteTestCase, skip_if_mobile, WindowManagerMixin
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_localization.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_localization.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import By
 from marionette_driver.errors import (
     InvalidArgumentException,
     NoSuchElementException,
     UnknownException
 )
 from marionette_driver.localization import L10n
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_marionette.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_marionette.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import socket
 import time
 
 from marionette_driver import errors
 from marionette_driver.marionette import Marionette
 from marionette_harness import MarionetteTestCase, run_if_manage_instance, skip_if_mobile
 
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_modal_dialogs.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_modal_dialogs.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.expected import element_present
 from marionette_driver import errors
 from marionette_driver.marionette import Alert
 from marionette_driver.wait import Wait
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_mouse_action.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_mouse_action.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 from marionette_driver.keys import Keys
 from marionette_driver.marionette import Actions
 
 from marionette_harness import MarionetteTestCase
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_navigation.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_navigation.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 import contextlib
 import os
 import urllib
 
 from marionette_driver import By, errors, expected, Wait
 from marionette_driver.keys import Keys
 from marionette_harness import (
     MarionetteTestCase,
@@ -700,26 +705,26 @@ class TestTLSNavigation(MarionetteTestCa
         self.marionette.navigate(
             inline("<a href=%s>https is the future</a>" % link_url))
         self.marionette.find_element(By.TAG_NAME, "a").click()
         self.assertIn("https", self.marionette.get_url())
 
     def test_deactivation(self):
         invalid_cert_url = self.test_page_insecure
 
-        print "with safe session"
+        print("with safe session")
         with self.safe_session() as session:
             with self.assertRaises(errors.InsecureCertificateException):
                 session.navigate(invalid_cert_url)
 
-        print "with unsafe session"
+        print("with unsafe session")
         with self.unsafe_session() as session:
             session.navigate(invalid_cert_url)
 
-        print "with safe session again"
+        print("with safe session again")
         with self.safe_session() as session:
             with self.assertRaises(errors.InsecureCertificateException):
                 session.navigate(invalid_cert_url)
 
 
 class TestPageLoadStrategy(BaseNavigationTestCase):
 
     def tearDown(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_pagesource.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_pagesource.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestPageSource(MarionetteTestCase):
     def testShouldReturnTheSourceOfAPage(self):
         test_html = self.marionette.absolute_url("testPageSource.html")
         self.marionette.navigate(test_html)
         source = self.marionette.page_source

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_pagesource_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_pagesource_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestPageSourceChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):
         super(TestPageSourceChrome, self).setUp()
         self.marionette.set_context("chrome")

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_position.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_position.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestPosition(MarionetteTestCase):
 
     def test_should_get_element_position_back(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_prefs.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_prefs.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import JavascriptException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestPreferences(MarionetteTestCase):
     prefs = {
         "bool": "marionette.test.bool",

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_profile_management.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_profile_management.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestProfileManagement(MarionetteTestCase):
 
     def setUp(self):
         MarionetteTestCase.setUp(self)
         self.marionette.enforce_gecko_prefs(

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_proxy.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_proxy.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import errors
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestProxyCapabilities(MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_quit_restart.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_quit_restart.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 import unittest
 
 from marionette_driver import errors
 
 from marionette_harness import MarionetteTestCase, skip
 
 
 class TestServerQuitApplication(MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_rendered_element.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_rendered_element.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 from marionette_harness import MarionetteTestCase
 
 
 def inline(doc):
     return "data:text/html;charset=utf-8,{}".format(urllib.quote(doc))

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_report.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_report.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, expectedFailure, skip
 
 
 class TestReport(MarionetteTestCase):
 
     def test_pass(self):
         assert True
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_run_js_test.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_run_js_test.py
@@ -1,10 +1,12 @@
 # Any copyright is dedicated to the Public Domain.
 # http://creativecommons.org/publicdomain/zero/1.0/
 
+from __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestRunJSTest(MarionetteTestCase):
     def test_basic(self):
         self.run_js_test('test_simpletest_pass.js')
         self.run_js_test('test_simpletest_fail.js')

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_screen_orientation.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_screen_orientation.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import errors
 from mozrunner.devices.emulator_screen import EmulatorScreen
 
 from marionette_harness import MarionetteTestCase, skip_if_desktop, skip_if_mobile
 
 
 default_orientation = "portrait-primary"
 unknown_orientation = "Unknown screen orientation: {}"

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_screenshot.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_screenshot.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import base64
 import hashlib
 import imghdr
 import struct
 import urllib
 
 from marionette_driver import By
 from marionette_driver.errors import NoSuchElementException, NoSuchWindowException

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_select.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_select.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 def inline(doc):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_session.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_session.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import errors
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestSession(MarionetteTestCase):
     def setUp(self):
         super(TestSession, self).setUp()

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_shadow_dom.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_shadow_dom.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import (
     NoSuchElementException,
     StaleElementException,
     UnsupportedOperationException,
 )
 
 from marionette_harness import MarionetteTestCase

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_single_finger_desktop.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_single_finger_desktop.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 import sys
 
 from marionette_driver.errors import MarionetteException
 from marionette_driver import Actions, By
 
 from marionette_harness import MarionetteTestCase, skip
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_skip_setup.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_skip_setup.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, SkipTest
 
 
 class TestSetUpSkipped(MarionetteTestCase):
 
     testVar = {'test':'SkipTest'}
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_switch_frame.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_switch_frame.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import (
     JavascriptException,
     NoSuchFrameException,
 )
 
 from marionette_harness import MarionetteTestCase
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_switch_frame_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_switch_frame_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import JavascriptException
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestSwitchFrameChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_switch_window_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_switch_window_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 import sys
 from unittest import skipIf
 
 from marionette_driver import By
 
 # add this directory to the path
 sys.path.append(os.path.dirname(__file__))

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_switch_window_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_switch_window_content.py
@@ -1,12 +1,14 @@
 # This Source Code Form is subject to the terms of the Mozilla ublic
 # 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 __future__ import absolute_import
+
 from marionette_driver import Actions, By, Wait
 from marionette_driver.keys import Keys
 
 from marionette_harness import MarionetteTestCase, skip_if_mobile, WindowManagerMixin
 
 
 class TestSwitchToWindowContent(WindowManagerMixin, MarionetteTestCase):
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_teardown_context_preserved.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_teardown_context_preserved.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, SkipTest
 
 
 class TestTearDownContext(MarionetteTestCase):
     def setUp(self):
         MarionetteTestCase.setUp(self)
         self.marionette.set_context(self.marionette.CONTEXT_CHROME)
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_text.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_text.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_harness import MarionetteTestCase
 
 
 class TestText(MarionetteTestCase):
 
     def test_get_text(self):
         test_html = self.marionette.absolute_url("test.html")

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_text_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_text_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase, skip, WindowManagerMixin
 
 
 @skip("Disabled in bug 896043 and when working on Chrome code re-enable for bug 896046")
 class TestTextChrome(WindowManagerMixin, MarionetteTestCase):
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_timeouts.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_timeouts.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 from marionette_driver.errors import (
     MarionetteException,
     NoSuchElementException,
     ScriptTimeoutException,
 )
 from marionette_driver.marionette import HTMLElement
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_title.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_title.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 from marionette_harness import MarionetteTestCase, skip
 
 
 def inline(doc):
     return "data:text/html;charset=utf-8,{}".format(urllib.quote(doc))

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_title_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_title_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestTitleChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):
         super(TestTitleChrome, self).setUp()
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_transport.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_transport.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import json
 
 from marionette_driver.transport import (
     Command,
     Proto2Command,
     Proto2Response,
     Response,
 )

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_typing.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_typing.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import urllib
 
 from marionette_driver.by import By
 from marionette_driver.errors import ElementNotInteractableException
 from marionette_driver.keys import Keys
 
 from marionette_harness import MarionetteTestCase, skip, skip_if_mobile
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_visibility.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_visibility.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.by import By
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestVisibility(MarionetteTestCase):
 
     def testShouldAllowTheUserToTellIfAnElementIsDisplayedOrNot(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_wait.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_wait.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import sys
 import time
 
 from marionette_driver import errors, wait
 from marionette_driver.wait import Wait
 
 from marionette_harness import MarionetteTestCase
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_close_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_close_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestCloseWindow(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):
         super(TestCloseWindow, self).setUp()
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_close_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_close_content.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, skip_if_mobile, WindowManagerMixin
 
 
 class TestCloseWindow(WindowManagerMixin, MarionetteTestCase):
 
     def tearDown(self):
         self.close_all_windows()
         self.close_all_tabs()

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_fullscreen.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_fullscreen.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestWindowFullscreen(MarionetteTestCase):
 
     def setUp(self):
         MarionetteTestCase.setUp(self)
         self.max = self.marionette.execute_script("""

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_handles_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_handles_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import types
 
 from marionette_driver import By, errors, Wait
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestWindowHandles(WindowManagerMixin, MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_handles_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_handles_content.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import types
 
 from marionette_driver import By, errors, Wait
 
 from marionette_harness import MarionetteTestCase, skip_if_mobile, WindowManagerMixin
 
 
 class TestWindowHandles(WindowManagerMixin, MarionetteTestCase):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_management.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_management.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import By
 from marionette_driver.errors import NoSuchWindowException
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin, skip_if_mobile
 
 
 class TestNoSuchWindowContent(WindowManagerMixin, MarionetteTestCase):
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_maximize.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_maximize.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase
 
 
 class TestWindowMaximize(MarionetteTestCase):
 
     def setUp(self):
         MarionetteTestCase.setUp(self)
         self.max = self.marionette.execute_script("""

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_minimize.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_minimize.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import InvalidArgumentException
 
 from marionette_harness import MarionetteTestCase
 
 class TestWindowMinimize(MarionetteTestCase):
 
     def setUp(self):
         MarionetteTestCase.setUp(self)

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_rect.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_rect.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 from marionette_driver.errors import InvalidArgumentException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestPosition(MarionetteTestCase):
 
     def setUp(self):

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import os
 import sys
 
 # add this directory to the path
 sys.path.append(os.path.dirname(__file__))
 
 from test_window_status_content import TestNoSuchWindowContent
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_content.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_status_content.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver import By
 from marionette_driver.errors import NoSuchWindowException
 
 from marionette_harness import MarionetteTestCase, WindowManagerMixin, skip_if_mobile
 
 
 class TestNoSuchWindowContent(WindowManagerMixin, MarionetteTestCase):
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_window_type_chrome.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_window_type_chrome.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_harness import MarionetteTestCase, WindowManagerMixin
 
 
 class TestWindowTypeChrome(WindowManagerMixin, MarionetteTestCase):
 
     def setUp(self):
         super(TestWindowTypeChrome, self).setUp()
 

--- a/testing/marionette/harness/marionette_harness/tests/unit/test_with_using_context.py
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_with_using_context.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.decorators import using_context
 from marionette_driver.errors import MarionetteException
 
 from marionette_harness import MarionetteTestCase
 
 
 class TestSetContext(MarionetteTestCase):
     def setUp(self):

--- a/testing/marionette/harness/setup.py
+++ b/testing/marionette/harness/setup.py
@@ -1,8 +1,10 @@
+from __future__ import absolute_import
+
 import os
 import re
 
 from setuptools import find_packages, setup
 
 
 THIS_DIR = os.path.dirname(os.path.realpath(__name__))
 

--- a/testing/marionette/mach_commands.py
+++ b/testing/marionette/mach_commands.py
@@ -1,13 +1,17 @@
 # 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 __future__ import absolute_import, unicode_literals
+from __future__ import (
+    absolute_import,
+    print_function,
+    unicode_literals
+)
 
 import argparse
 import os
 import sys
 
 from mach.decorators import (
     CommandArgument,
     CommandProvider,
@@ -74,18 +78,18 @@ class MachCommands(MachCommandBase):
 
     @Command("marionette-test",
              category="testing",
              description="Remote control protocol to Gecko, used for functional UI tests and browser automation.",
              conditions=[is_firefox_or_android],
              parser=create_parser_tests,
              )
     def run_marionette_test(self, tests, **kwargs):
-        print >>sys.stderr, ("warning: ./mach marionette-test is deprecated; "
-                             "please use ./mach marionette test")
+        print (sys.stderr, ("warning: ./mach marionette-test is deprecated; "
+                             "please use ./mach marionette test"))
 
         if "test_objects" in kwargs:
             tests = []
             for obj in kwargs["test_objects"]:
                 tests.append(obj["file_relpath"])
             del kwargs["test_objects"]
 
         if not kwargs.get("binary") and conditions.is_firefox(self):
@@ -151,13 +155,13 @@ class Marionette(MachCommandBase):
 
             host, port = http.split(":")
             host = host or "127.0.0.1"
             port = int(port)
 
             handler = SimpleHTTPServer.SimpleHTTPRequestHandler
             httpd = SocketServer.TCPServer((host, int(port)), handler)
 
-            print "serving at %s:%s" % (host, port)
+            print("serving at %s:%s" % (host, port))
             os.chdir(os.path.join(self.srcdir, "doc"))
             httpd.serve_forever()
 
         return proc.returncode

--- a/testing/marionette/mach_test_package_commands.py
+++ b/testing/marionette/mach_test_package_commands.py
@@ -1,12 +1,17 @@
 # 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 __future__ import (
+    absolute_import, 
+    print_function
+)
+
 import argparse
 import os
 import sys
 from functools import partial
 
 from mach.decorators import (
     CommandProvider,
     Command,

--- a/testing/marionette/puppeteer/firefox/docs/conf.py
+++ b/testing/marionette/puppeteer/firefox/docs/conf.py
@@ -7,16 +7,18 @@
 # containing dir.
 #
 # Note that not all possible configuration values are present in this
 # autogenerated file.
 #
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
+from __future__ import absolute_import
+
 import os
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 # sys.path.insert(0, os.path.abspath('.'))
 
 # -- General configuration ------------------------------------------------

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/__init__.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/__init__.py
@@ -1,9 +1,11 @@
 # 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 __future__ import absolute_import
+
 from firefox_puppeteer.mixins import PuppeteerMixin
 from firefox_puppeteer.puppeteer import Puppeteer
 
 
 __version__ = '52.1.0'

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/appinfo.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/appinfo.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from firefox_puppeteer.base import BaseLib
 
 
 class AppInfo(BaseLib):
     """This class provides access to various attributes of AppInfo.
 
     For more details on AppInfo, visit:
     https://developer.mozilla.org/en-US/docs/Mozilla/QA/Mozmill_tests/Shared_Modules/UtilsAPI/appInfo

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/keys.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/keys.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import marionette_driver
 
 
 class Keys(marionette_driver.keys.Keys):
     """Proxy to marionette's keys with an "accel" provided for convenience
     testing across platforms."""
 
     def __init__(self, marionette):

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/l10n.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/l10n.py
@@ -3,16 +3,18 @@
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
 # -----------------
 # DEPRECATED module
 # -----------------
 # Replace its use in tests when Firefox 45 ESR support ends with
 # marionette_driver.localization.L10n
 
+from __future__ import absolute_import
+
 import copy
 
 from marionette_driver.errors import (
     NoSuchElementException,
     UnknownCommandException,
 )
 from marionette_driver.localization import L10n as L10nMarionette
 

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/places.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/places.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from collections import namedtuple
 from time import sleep
 
 from marionette_driver.errors import MarionetteException
 
 from firefox_puppeteer.base import BaseLib
 
 

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/security.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/security.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import re
 
 from firefox_puppeteer.base import BaseLib
 from firefox_puppeteer.errors import NoCertificateError
 
 
 class Security(BaseLib):
     """Low-level access to security (SSL, TLS) related information."""

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/software_update.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/software_update.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 import ConfigParser
 import os
 import re
 import sys
 
 import mozinfo
 
 from firefox_puppeteer.base import BaseLib
@@ -361,18 +363,18 @@ class SoftwareUpdate(BaseLib):
         :param update_url: URL to the update snippet
         """
         import urllib2
         try:
             response = urllib2.urlopen(update_url)
             return response.read()
         except urllib2.URLError:
             exc, val, tb = sys.exc_info()
-            raise Exception, "Failed to retrieve update snippet '{}': {}".format(
-                update_url, val), tb
+            raise Exception("Failed to retrieve update snippet '{}': {}".format(
+                update_url, val), tb)
 
     def get_formatted_update_url(self, force=False):
         """Retrieve the formatted AUS update URL the update snippet is retrieved from.
 
         :param force: Boolean flag to force an update check
 
         :returns: The URL of the update snippet
         """

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/utils.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/api/utils.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from marionette_driver.errors import MarionetteException
 
 from firefox_puppeteer.base import BaseLib
 
 
 class Utils(BaseLib):
     """Low-level access to utility actions."""
 

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/base.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/base.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 
 class BaseLib(object):
     """A base class that handles lazily setting the "client" class attribute."""
 
     def __init__(self, marionette):
         self._marionette = marionette
 
     @property

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/decorators.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/decorators.py
@@ -1,12 +1,14 @@
 # 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 __future__ import absolute_import
+
 from functools import wraps
 from importlib import import_module
 
 
 class use_class_as_property(object):
     """
     This decorator imports a library module and sets an instance
     of the associated class as an attribute on the Puppeteer