--- a/testing/mozbase/mozprocess/mozprocess/processhandler.py
+++ b/testing/mozbase/mozprocess/mozprocess/processhandler.py
@@ -8,17 +8,20 @@ import errno
 import os
 import signal
 import subprocess
 import sys
 import threading
 import time
 import traceback
 
-from Queue import Queue, Empty
+try:
+    from queue import Queue, Empty
+except ImportError:
+    from Queue import Queue, Empty
 from datetime import datetime
 
 
 __all__ = ['ProcessHandlerMixin', 'ProcessHandler', 'LogOutput',
            'StoreOutput', 'StreamOutput']
 
 # Set the MOZPROCESS_DEBUG environment variable to 1 to see some debugging output
 MOZPROCESS_DEBUG = os.getenv("MOZPROCESS_DEBUG")
@@ -119,24 +122,24 @@ class ProcessHandlerMixin(object):
                 raise
 
         def debug(self, msg):
             if not MOZPROCESS_DEBUG:
                 return
             thread = threading.current_thread().name
             print("DBG::MOZPROC PID:{} ({}) | {}".format(self.pid, thread, msg))
 
-        def __del__(self, _maxint=sys.maxint):
+        def __del__(self, _maxint=sys.maxsize):
             if isWin:
                 handle = getattr(self, '_handle', None)
                 if handle:
                     if hasattr(self, '_internal_poll'):
                         self._internal_poll(_deadstate=_maxint)
                     else:
-                        self.poll(_deadstate=sys.maxint)
+                        self.poll(_deadstate=sys.maxsize)
                 if handle or self._job or self._io_port:
                     self._cleanup()
             else:
                 subprocess.Popen.__del__(self)
 
         def kill(self, sig=None):
             if isWin:
                 try:
@@ -1064,17 +1067,17 @@ class StoreOutput(object):
 class StreamOutput(object):
     """pass output to a stream and flush"""
 
     def __init__(self, stream):
         self.stream = stream
 
     def __call__(self, line):
         try:
-            self.stream.write(line + '\n')
+            self.stream.write(line.decode() + '\n')
         except UnicodeDecodeError:
             # TODO: Workaround for bug #991866 to make sure we can display when
             # when normal UTF-8 display is failing
             self.stream.write(line.decode('iso8859-1') + '\n')
         self.stream.flush()
 
 
 class LogOutput(StreamOutput):

--- a/testing/mozbase/mozprocess/setup.py
+++ b/testing/mozbase/mozprocess/setup.py
@@ -1,28 +1,29 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from __future__ import absolute_import
 
 from setuptools import setup
 
-PACKAGE_VERSION = '0.26'
+PACKAGE_VERSION = '1.0.0'
 
 setup(name='mozprocess',
       version=PACKAGE_VERSION,
       description="Mozilla-authored process handling",
       long_description="see https://firefox-source-docs.mozilla.org/mozbase/index.html",
       classifiers=['Environment :: Console',
                    'Intended Audience :: Developers',
                    'License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)',
                    'Natural Language :: English',
                    'Operating System :: OS Independent',
-                   'Programming Language :: Python',
+                   'Programming Language :: Python :: 2.7',
+                   'Programming Language :: Python :: 3.5'
                    'Topic :: Software Development :: Libraries :: Python Modules',
                    ],
       keywords='mozilla',
       author='Mozilla Automation and Tools team',
       author_email='tools@lists.mozilla.org',
       url='https://wiki.mozilla.org/Auto-tools/Projects/Mozbase',
       license='MPL 2.0',
       packages=['mozprocess'],

--- a/testing/mozbase/mozprocess/tests/manifest.ini
+++ b/testing/mozbase/mozprocess/tests/manifest.ini
@@ -1,10 +1,9 @@
 [DEFAULT]
 subsuite = mozbase, os == "linux"
-skip-if = python == 3
 [test_kill.py]
 [test_misc.py]
 [test_poll.py]
 [test_wait.py]
 [test_output.py]
 [test_params.py]
 [test_process_reader.py]

--- a/testing/mozbase/mozprocess/tests/proclaunch.py
+++ b/testing/mozbase/mozprocess/tests/proclaunch.py
@@ -1,15 +1,18 @@
 #!/usr/bin/env python
 
 from __future__ import absolute_import, print_function
 
 import argparse
 import collections
-import ConfigParser
+try:
+    import configparser as ConfigParser
+except ImportError:
+    import ConfigParser
 import multiprocessing
 import time
 
 ProcessNode = collections.namedtuple('ProcessNode', ['maxtime', 'children'])
 
 
 class ProcessLauncher(object):
 

--- a/testing/mozbase/mozprocess/tests/test_output.py
+++ b/testing/mozbase/mozprocess/tests/test_output.py
@@ -1,19 +1,19 @@
 #!/usr/bin/env python
 
 from __future__ import absolute_import
 
-import io
 import os
 
 import mozunit
 
 import proctest
 from mozprocess import processhandler
+import six
 
 here = os.path.dirname(os.path.abspath(__file__))
 
 
 class ProcTestOutput(proctest.ProcTest):
     """ Class to test operations related to output handling """
 
     def test_process_output_twice(self):
@@ -44,34 +44,32 @@ class ProcTestOutput(proctest.ProcTest):
         self.determine_status(p, False, ())
 
     def test_stream_process_output(self):
         """
         Process output stream does not buffer
         """
         expected = '\n'.join([str(n) for n in range(0, 10)])
 
-        stream = io.BytesIO()
-        buf = io.BufferedRandom(stream)
+        stream = six.StringIO()
 
         p = processhandler.ProcessHandler([self.python,
                                            os.path.join("scripts", "proccountfive.py")],
                                           cwd=here,
-                                          stream=buf)
+                                          stream=stream)
 
         p.run()
         p.wait()
         for i in range(5, 10):
             stream.write(str(i) + '\n')
 
-        buf.flush()
         self.assertEquals(stream.getvalue().strip(), expected)
 
         # make sure mozprocess doesn't close the stream
         # since mozprocess didn't create it
-        self.assertFalse(buf.closed)
-        buf.close()
+        self.assertFalse(stream.closed)
+        stream.close()
 
         self.determine_status(p, False, ())
 
 
 if __name__ == '__main__':
     mozunit.main()

--- a/testing/mozbase/mozprocess/tests/test_process_reader.py
+++ b/testing/mozbase/mozprocess/tests/test_process_reader.py
@@ -28,38 +28,38 @@ class TestProcessReader(unittest.TestCas
         def on_timeout():
             self.timeout = True
         self.reader = ProcessReader(stdout_callback=self.out,
                                     stderr_callback=self.err,
                                     finished_callback=on_finished,
                                     timeout_callback=on_timeout)
 
     def test_stdout_callback(self):
-        proc = run_python('print 1; print 2')
+        proc = run_python('print(1); print(2)')
         self.reader.start(proc)
         self.reader.thread.join()
 
-        self.assertEqual(self.out.output, ['1', '2'])
+        self.assertEqual(self.out.output, [b'1', b'2'])
         self.assertEqual(self.err.output, [])
 
     def test_stderr_callback(self):
         proc = run_python('import sys; sys.stderr.write("hello world\\n")')
         self.reader.start(proc)
         self.reader.thread.join()
 
         self.assertEqual(self.out.output, [])
-        self.assertEqual(self.err.output, ['hello world'])
+        self.assertEqual(self.err.output, [b'hello world'])
 
     def test_stdout_and_stderr_callbacks(self):
-        proc = run_python('import sys; sys.stderr.write("hello world\\n"); print 1; print 2')
+        proc = run_python('import sys; sys.stderr.write("hello world\\n"); print(1); print(2)')
         self.reader.start(proc)
         self.reader.thread.join()
 
-        self.assertEqual(self.out.output, ['1', '2'])
-        self.assertEqual(self.err.output, ['hello world'])
+        self.assertEqual(self.out.output, [b'1', b'2'])
+        self.assertEqual(self.err.output, [b'hello world'])
 
     def test_finished_callback(self):
         self.assertFalse(self.finished)
         proc = run_python('')
         self.reader.start(proc)
         self.reader.thread.join()
         self.assertTrue(self.finished)
 
@@ -80,28 +80,28 @@ class TestProcessReader(unittest.TestCas
         self.reader.thread.join()
         self.assertTrue(self.timeout)
         self.assertFalse(self.finished)
 
     def test_read_without_eol(self):
         proc = run_python('import sys; sys.stdout.write("1")')
         self.reader.start(proc)
         self.reader.thread.join()
-        self.assertEqual(self.out.output, ['1'])
+        self.assertEqual(self.out.output, [b'1'])
 
     def test_read_with_strange_eol(self):
         proc = run_python('import sys; sys.stdout.write("1\\r\\r\\r\\n")')
         self.reader.start(proc)
         self.reader.thread.join()
-        self.assertEqual(self.out.output, ['1'])
+        self.assertEqual(self.out.output, [b'1'])
 
     def test_mixed_stdout_stderr(self):
-        proc = run_python('import sys; sys.stderr.write("hello world\\n"); print 1; print 2',
+        proc = run_python('import sys; sys.stderr.write("hello world\\n"); print(1); print(2)',
                           stderr=subprocess.STDOUT)
         self.reader.start(proc)
         self.reader.thread.join()
 
-        self.assertEqual(sorted(self.out.output), sorted(['1', '2', 'hello world']))
+        self.assertEqual(sorted(self.out.output), sorted([b'1', b'2', b'hello world']))
         self.assertEqual(self.err.output, [])
 
 
 if __name__ == '__main__':
     mozunit.main()

--- a/testing/mozbase/mozrunner/setup.py
+++ b/testing/mozbase/mozrunner/setup.py
@@ -11,17 +11,17 @@ PACKAGE_VERSION = '7.0.1'
 
 desc = """Reliable start/stop/configuration of Mozilla Applications (Firefox, Thunderbird, etc.)"""
 
 deps = [
     'mozdevice>=1.*',
     'mozfile==1.*',
     'mozinfo>=0.7,<2',
     'mozlog==3.*',
-    'mozprocess>=0.23,<1',
+    'mozprocess>=0.23,<2',
     'mozprofile>=1.1.0,<2',
     'six>=1.10.0,<2',
 ]
 
 EXTRAS_REQUIRE = {'crash': ['mozcrash >= 1.0']}
 
 
 setup(name=PACKAGE_NAME,

--- a/testing/tps/setup.py
+++ b/testing/tps/setup.py
@@ -8,17 +8,17 @@ import sys
 
 version = '0.6'
 
 deps = ['httplib2 == 0.9.2',
         'mozfile == 1.2',
         'mozhttpd == 0.7',
         'mozinfo >= 0.10',
         'mozinstall == 1.16',
-        'mozprocess == 0.26',
+        'mozprocess == 1.0.0',
         'mozprofile == 1.1.0',
         'mozrunner == 7.0.1',
         'mozversion == 1.5',
        ]
 
 # we only support python 2.6+ right now
 assert sys.version_info[0] == 2
 assert sys.version_info[1] >= 6