diff --git a/js/src/jit-test/jit_test.py b/js/src/jit-test/jit_test.py
index 2808d2fa5432..18669a0d9cc2 100755
--- a/js/src/jit-test/jit_test.py
+++ b/js/src/jit-test/jit_test.py
@@ -15,19 +15,23 @@ import sys
 import traceback
 
 
-def add_libdir_to_path():
+def add_tests_dir_to_path():
     from os.path import dirname, exists, join, realpath
     js_src_dir = dirname(dirname(realpath(sys.argv[0])))
     assert exists(join(js_src_dir, 'jsapi.h'))
-    sys.path.insert(0, join(js_src_dir, 'lib'))
-    sys.path.insert(0, join(js_src_dir, 'tests', 'lib'))
+    sys.path.insert(0, join(js_src_dir, 'tests'))
 
 
-add_libdir_to_path()
+add_tests_dir_to_path()
 
-import jittests
-from tests import get_jitflags, valid_jitflags, get_cpu_count, get_environment_overlay, \
-    change_env
+from lib import jittests
+from lib.tests import (
+    get_jitflags,
+    valid_jitflags,
+    get_cpu_count,
+    get_environment_overlay,
+    change_env,
+)
 
 
 def which(name):
@@ -66,135 +70,132 @@ def choose_item(jobs, max_items, display):
 def main(argv):
     # The [TESTS] optional arguments are paths of test files relative
     # to the jit-test/tests directory.
-    from optparse import OptionParser, SUPPRESS_HELP
-    op = OptionParser(usage='%prog [options] JS_SHELL [TESTS]')
-    op.add_option('-s', '--show-cmd', dest='show_cmd', action='store_true',
-                  help='show js shell command run')
-    op.add_option('-f', '--show-failed-cmd', dest='show_failed',
-                  action='store_true',
-                  help='show command lines of failed tests')
-    op.add_option('-o', '--show-output', dest='show_output',
-                  action='store_true',
-                  help='show output from js shell')
-    op.add_option('-F', '--failed-only', dest='failed_only',
-                  action='store_true',
-                  help="if --show-output is given, only print output for"
-                  " failed tests")
-    op.add_option('--no-show-failed', dest='no_show_failed',
-                  action='store_true',
-                  help="don't print output for failed tests"
-                  " (no-op with --show-output)")
-    op.add_option('-x', '--exclude', dest='exclude',
-                  default=[], action='append',
-                  help='exclude given test dir or path')
-    op.add_option('--exclude-from', dest='exclude_from', type=str,
-                  help='exclude each test dir or path in FILE')
-    op.add_option('--slow', dest='run_slow', action='store_true',
-                  help='also run tests marked as slow')
-    op.add_option('--no-slow', dest='run_slow', action='store_false',
-                  help='do not run tests marked as slow (the default)')
-    op.add_option('-t', '--timeout', dest='timeout', type=float, default=150.0,
-                  help='set test timeout in seconds')
-    op.add_option('--no-progress', dest='hide_progress', action='store_true',
-                  help='hide progress bar')
-    op.add_option('--tinderbox', dest='format', action='store_const',
-                  const='automation',
-                  help='Use automation-parseable output format')
-    op.add_option('--format', dest='format', default='none', type='choice',
-                  choices=['automation', 'none'],
-                  help='Output format. Either automation or none'
-                  ' (default %default).')
-    op.add_option('--args', dest='shell_args', metavar='ARGS', default='',
-                  help='extra args to pass to the JS shell')
-    op.add_option('--feature-args', dest='feature_args', metavar='ARGS',
-                  default='',
-                  help='even more args to pass to the JS shell '
-                       '(for compatibility with jstests.py)')
-    op.add_option('-w', '--write-failures', dest='write_failures',
-                  metavar='FILE',
-                  help='Write a list of failed tests to [FILE]')
-    op.add_option('-C', '--check-output', action='store_true', dest='check_output',
-                  help='Run tests to check output for different jit-flags')
-    op.add_option('-r', '--read-tests', dest='read_tests', metavar='FILE',
-                  help='Run test files listed in [FILE]')
-    op.add_option('-R', '--retest', dest='retest', metavar='FILE',
-                  help='Retest using test list file [FILE]')
-    op.add_option('-g', '--debug', action='store_const', const='gdb', dest='debugger',
-                  help='Run a single test under the gdb debugger')
-    op.add_option('-G', '--debug-rr', action='store_const', const='rr', dest='debugger',
-                  help='Run a single test under the rr debugger')
-    op.add_option('--debugger', type='string',
-                  help='Run a single test under the specified debugger')
-    op.add_option('--valgrind', dest='valgrind', action='store_true',
-                  help='Enable the |valgrind| flag, if valgrind is in $PATH.')
-    op.add_option('--unusable-error-status', action='store_true',
-                  help='Ignore incorrect exit status on tests that should return nonzero.')
-    op.add_option('--valgrind-all', dest='valgrind_all', action='store_true',
-                  help='Run all tests with valgrind, if valgrind is in $PATH.')
-    op.add_option('--avoid-stdio', dest='avoid_stdio', action='store_true',
-                  help='Use js-shell file indirection instead of piping stdio.')
-    op.add_option('--write-failure-output', dest='write_failure_output',
-                  action='store_true',
-                  help='With --write-failures=FILE, additionally write the'
-                  ' output of failed tests to [FILE]')
-    op.add_option('--jitflags', dest='jitflags', default='none',
-                  choices=valid_jitflags(),
-                  help='IonMonkey option combinations. One of %s.' % ', '.join(valid_jitflags()))
-    op.add_option('--ion', dest='jitflags', action='store_const', const='ion',
-                  help='Run tests once with --ion-eager and once with'
-                  ' --baseline-eager (equivalent to --jitflags=ion)')
-    op.add_option('--tbpl', dest='jitflags', action='store_const', const='all',
-                  help='Run tests with all IonMonkey option combinations'
-                  ' (equivalent to --jitflags=all)')
-    op.add_option('-j', '--worker-count', dest='max_jobs', type=int,
-                  default=max(1, get_cpu_count()),
-                  help='Number of tests to run in parallel (default %default)')
-    op.add_option('--remote', action='store_true',
-                  help='Run tests on a remote device')
-    op.add_option('--deviceIP', action='store',
-                  type='string', dest='device_ip',
-                  help='IP address of remote device to test')
-    op.add_option('--devicePort', action='store',
-                  type=int, dest='device_port', default=20701,
-                  help='port of remote device to test')
-    op.add_option('--deviceSerial', action='store',
-                  type='string', dest='device_serial', default=None,
-                  help='ADB device serial number of remote device to test')
-    op.add_option('--remoteTestRoot', dest='remote_test_root', action='store',
-                  type='string', default='/data/local/tests',
-                  help='The remote directory to use as test root'
-                  ' (eg. /data/local/tests)')
-    op.add_option('--localLib', dest='local_lib', action='store',
-                  type='string',
-                  help='The location of libraries to push -- preferably'
-                  ' stripped')
-    op.add_option('--repeat', type=int, default=1,
-                  help='Repeat tests the given number of times.')
-    op.add_option('--this-chunk', type=int, default=1,
-                  help='The test chunk to run.')
-    op.add_option('--total-chunks', type=int, default=1,
-                  help='The total number of test chunks.')
-    op.add_option('--ignore-timeouts', dest='ignore_timeouts', metavar='FILE',
-                  help='Ignore timeouts of tests listed in [FILE]')
-    op.add_option('--test-reflect-stringify', dest="test_reflect_stringify",
-                  help="instead of running tests, use them to test the "
-                  "Reflect.stringify code in specified file")
-    op.add_option('--run-binast', action='store_true',
-                  dest="run_binast",
-                  help="By default BinAST testcases encoded from JS "
-                  "testcases are skipped. If specified, BinAST testcases "
-                  "are also executed.")
+    import argparse
+    op = argparse.ArgumentParser(description='Run jit-test JS shell tests')
+    op.add_argument('-s', '--show-cmd', dest='show_cmd', action='store_true',
+                    help='show js shell command run')
+    op.add_argument('-f', '--show-failed-cmd', dest='show_failed',
+                    action='store_true',
+                    help='show command lines of failed tests')
+    op.add_argument('-o', '--show-output', dest='show_output',
+                    action='store_true',
+                    help='show output from js shell')
+    op.add_argument('-F', '--failed-only', dest='failed_only',
+                    action='store_true',
+                    help="if --show-output is given, only print output for"
+                    " failed tests")
+    op.add_argument('--no-show-failed', dest='no_show_failed',
+                    action='store_true',
+                    help="don't print output for failed tests"
+                    " (no-op with --show-output)")
+    op.add_argument('-x', '--exclude', dest='exclude',
+                    default=[], action='append',
+                    help='exclude given test dir or path')
+    op.add_argument('--exclude-from', dest='exclude_from', type=str,
+                    help='exclude each test dir or path in FILE')
+    op.add_argument('--slow', dest='run_slow', action='store_true',
+                    help='also run tests marked as slow')
+    op.add_argument('--no-slow', dest='run_slow', action='store_false',
+                    help='do not run tests marked as slow (the default)')
+    op.add_argument('-t', '--timeout', dest='timeout', type=float, default=150.0,
+                    help='set test timeout in seconds')
+    op.add_argument('--no-progress', dest='hide_progress', action='store_true',
+                    help='hide progress bar')
+    op.add_argument('--tinderbox', dest='format', action='store_const',
+                    const='automation',
+                    help='Use automation-parseable output format')
+    op.add_argument('--format', dest='format', default='none',
+                    choices=('automation', 'none'),
+                    help='Output format (default %(default)s).')
+    op.add_argument('--args', dest='shell_args', metavar='ARGS', default='',
+                    help='extra args to pass to the JS shell')
+    op.add_argument('--feature-args', dest='feature_args', metavar='ARGS',
+                    default='',
+                    help='even more args to pass to the JS shell '
+                    '(for compatibility with jstests.py)')
+    op.add_argument('-w', '--write-failures', dest='write_failures',
+                    metavar='FILE',
+                    help='Write a list of failed tests to [FILE]')
+    op.add_argument('-C', '--check-output', action='store_true', dest='check_output',
+                    help='Run tests to check output for different jit-flags')
+    op.add_argument('-r', '--read-tests', dest='read_tests', metavar='FILE',
+                    help='Run test files listed in [FILE]')
+    op.add_argument('-R', '--retest', dest='retest', metavar='FILE',
+                    help='Retest using test list file [FILE]')
+    op.add_argument('-g', '--debug', action='store_const', const='gdb', dest='debugger',
+                    help='Run a single test under the gdb debugger')
+    op.add_argument('-G', '--debug-rr', action='store_const', const='rr', dest='debugger',
+                    help='Run a single test under the rr debugger')
+    op.add_argument('--debugger', type=str,
+                    help='Run a single test under the specified debugger')
+    op.add_argument('--valgrind', dest='valgrind', action='store_true',
+                    help='Enable the |valgrind| flag, if valgrind is in $PATH.')
+    op.add_argument('--unusable-error-status', action='store_true',
+                    help='Ignore incorrect exit status on tests that should return nonzero.')
+    op.add_argument('--valgrind-all', dest='valgrind_all', action='store_true',
+                    help='Run all tests with valgrind, if valgrind is in $PATH.')
+    op.add_argument('--avoid-stdio', dest='avoid_stdio', action='store_true',
+                    help='Use js-shell file indirection instead of piping stdio.')
+    op.add_argument('--write-failure-output', dest='write_failure_output',
+                    action='store_true',
+                    help='With --write-failures=FILE, additionally write the'
+                    ' output of failed tests to [FILE]')
+    op.add_argument('--jitflags', dest='jitflags', default='none',
+                    choices=valid_jitflags(),
+                    help='IonMonkey option combinations (default %(default)s).')
+    op.add_argument('--ion', dest='jitflags', action='store_const', const='ion',
+                    help='Run tests once with --ion-eager and once with'
+                    ' --baseline-eager (equivalent to --jitflags=ion)')
+    op.add_argument('--tbpl', dest='jitflags', action='store_const', const='all',
+                    help='Run tests with all IonMonkey option combinations'
+                    ' (equivalent to --jitflags=all)')
+    op.add_argument('-j', '--worker-count', dest='max_jobs', type=int,
+                    default=max(1, get_cpu_count()),
+                    help='Number of tests to run in parallel (default %(default)s).')
+    op.add_argument('--remote', action='store_true',
+                    help='Run tests on a remote device')
+    op.add_argument('--deviceIP', action='store',
+                    type=str, dest='device_ip',
+                    help='IP address of remote device to test')
+    op.add_argument('--devicePort', action='store',
+                    type=int, dest='device_port', default=20701,
+                    help='port of remote device to test')
+    op.add_argument('--deviceSerial', action='store',
+                    type=str, dest='device_serial', default=None,
+                    help='ADB device serial number of remote device to test')
+    op.add_argument('--remoteTestRoot', dest='remote_test_root', action='store',
+                    type=str, default='/data/local/tests',
+                    help='The remote directory to use as test root'
+                    ' (eg. /data/local/tests)')
+    op.add_argument('--localLib', dest='local_lib', action='store',
+                    type=str,
+                    help='The location of libraries to push -- preferably'
+                    ' stripped')
+    op.add_argument('--repeat', type=int, default=1,
+                    help='Repeat tests the given number of times.')
+    op.add_argument('--this-chunk', type=int, default=1,
+                    help='The test chunk to run.')
+    op.add_argument('--total-chunks', type=int, default=1,
+                    help='The total number of test chunks.')
+    op.add_argument('--ignore-timeouts', dest='ignore_timeouts', metavar='FILE',
+                    help='Ignore timeouts of tests listed in [FILE]')
+    op.add_argument('--test-reflect-stringify', dest="test_reflect_stringify",
+                    help="instead of running tests, use them to test the "
+                    "Reflect.stringify code in specified file")
+    op.add_argument('--run-binast', action='store_true',
+                    dest="run_binast",
+                    help="By default BinAST testcases encoded from JS "
+                    "testcases are skipped. If specified, BinAST testcases "
+                    "are also executed.")
     # --enable-webrender is ignored as it is not relevant for JIT
     # tests, but is required for harness compatibility.
-    op.add_option('--enable-webrender', action='store_true',
-                  dest="enable_webrender", default=False,
-                  help=SUPPRESS_HELP)
+    op.add_argument('--enable-webrender', action='store_true',
+                    dest="enable_webrender", default=False,
+                    help=argparse.SUPPRESS)
+    op.add_argument('js_shell', metavar='JS_SHELL', help='JS shell to run tests with')
 
-    options, args = op.parse_args(argv)
-    if len(args) < 1:
-        op.error('missing JS_SHELL argument')
-    js_shell = which(args[0])
-    test_args = args[1:]
+    options, test_args = op.parse_known_args(argv)
+    js_shell = which(options.js_shell)
     test_environment = get_environment_overlay(js_shell)
 
     if not (os.path.isfile(js_shell) and os.access(js_shell, os.X_OK)):
diff --git a/js/src/jit-test/tests/basic/bug1033946.js b/js/src/jit-test/tests/basic/bug1033946.js
index a9dda468cbd2..e2f07a8532ef 100644
--- a/js/src/jit-test/tests/basic/bug1033946.js
+++ b/js/src/jit-test/tests/basic/bug1033946.js
@@ -1,3 +1,2 @@
-
 assertEq((/(?!(?!(?!6)[\Wc]))/i).test(), false);
 assertEq("foobar\xff5baz\u1200".search(/bar\u0178\d/i), 3);
diff --git a/js/src/tests/lib/jittests.py b/js/src/tests/lib/jittests.py
index 7ba9bdba60df..19eccda73de1 100755
--- a/js/src/tests/lib/jittests.py
+++ b/js/src/tests/lib/jittests.py
@@ -16,13 +16,13 @@ from collections import namedtuple
 from datetime import datetime
 
 if sys.platform.startswith('linux') or sys.platform.startswith('darwin'):
-    from tasks_unix import run_all_tests
+    from .tasks_unix import run_all_tests
 else:
-    from tasks_win import run_all_tests
+    from .tasks_win import run_all_tests
 
-from progressbar import ProgressBar, NullProgressBar
-from results import TestOutput, escape_cmdline
-from structuredlog import TestLogger
+from .progressbar import ProgressBar, NullProgressBar
+from .results import TestOutput, escape_cmdline
+from .structuredlog import TestLogger
 
 TESTS_LIB_DIR = os.path.dirname(os.path.abspath(__file__))
 JS_DIR = os.path.dirname(os.path.dirname(TESTS_LIB_DIR))
@@ -203,7 +203,7 @@ class JitTest:
         # For each list of jit flags, make a copy of the test.
         return [self.copy_and_extend_jitflags(v) for v in variants]
 
-    COOKIE = '|jit-test|'
+    COOKIE = b'|jit-test|'
 
     # We would use 500019 (5k19), but quit() only accepts values up to 127, due to fuzzers
     SKIPPED_EXIT_STATUS = 59
@@ -212,10 +212,10 @@ class JitTest:
     @classmethod
     def find_directives(cls, file_name):
         meta = ''
-        line = open(file_name).readline()
+        line = open(file_name, "rb").readline()
         i = line.find(cls.COOKIE)
         if i != -1:
-            meta = ';' + line[i + len(cls.COOKIE):].strip('\n')
+            meta = ';' + line[i + len(cls.COOKIE):].decode(errors='strict').strip('\n')
         return meta
 
     @classmethod
diff --git a/js/src/tests/lib/manifest.py b/js/src/tests/lib/manifest.py
index bac4afcf3ad2..7c57a8956d11 100644
--- a/js/src/tests/lib/manifest.py
+++ b/js/src/tests/lib/manifest.py
@@ -9,7 +9,7 @@ import re
 import sys
 from subprocess import Popen, PIPE
 
-from tests import RefTestCase
+from .tests import RefTestCase
 
 
 def split_path_into_dirs(path):
@@ -106,7 +106,7 @@ class XULInfoTester:
                 '-e', self.js_prologue,
                 '-e', 'print(!!({}))'.format(cond)
             ]
-            p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
+            p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, universal_newlines=True)
             out, err = p.communicate()
             if out in ('true\n', 'true\r\n'):
                 ans = True
diff --git a/js/src/tests/lib/progressbar.py b/js/src/tests/lib/progressbar.py
index 5faa2e19fefa..4ee11d524cf1 100644
--- a/js/src/tests/lib/progressbar.py
+++ b/js/src/tests/lib/progressbar.py
@@ -1,13 +1,14 @@
 # Text progress bar library, like curl or scp.
 
-from datetime import datetime, timedelta
 import math
 import sys
 
+from datetime import datetime, timedelta
+
 if sys.platform.startswith('win'):
-    from terminal_win import Terminal
+    from .terminal_win import Terminal
 else:
-    from terminal_unix import Terminal
+    from .terminal_unix import Terminal
 
 
 class NullProgressBar(object):
diff --git a/js/src/tests/lib/results.py b/js/src/tests/lib/results.py
index 77477a407df6..7a51feaaf501 100644
--- a/js/src/tests/lib/results.py
+++ b/js/src/tests/lib/results.py
@@ -4,8 +4,8 @@ import json
 import pipes
 import re
 
-from progressbar import NullProgressBar, ProgressBar
-from structuredlog import TestLogger
+from .progressbar import NullProgressBar, ProgressBar
+from .structuredlog import TestLogger
 
 # subprocess.list2cmdline does not properly escape for sh-like shells
 
diff --git a/js/src/tests/lib/tasks_unix.py b/js/src/tests/lib/tasks_unix.py
index 40528b898d0f..9a3b8e715a99 100644
--- a/js/src/tests/lib/tasks_unix.py
+++ b/js/src/tests/lib/tasks_unix.py
@@ -7,9 +7,15 @@ import os
 import select
 import signal
 import sys
+
 from datetime import datetime, timedelta
-from progressbar import ProgressBar
-from results import NullTestOutput, TestOutput, escape_cmdline
+
+from .progressbar import ProgressBar
+from .results import (
+    NullTestOutput,
+    TestOutput,
+    escape_cmdline,
+)
 
 
 class Task(object):
@@ -186,8 +192,8 @@ def reap_zombies(tasks, timeout):
             TestOutput(
                 ended.test,
                 ended.cmd,
-                ''.join(ended.out),
-                ''.join(ended.err),
+                b''.join(ended.out).decode(errors='replace'),
+                b''.join(ended.err).decode(errors='replace'),
                 returncode,
                 (datetime.now() - ended.start).total_seconds(),
                 timed_out(ended, timeout),
diff --git a/js/src/tests/lib/tasks_win.py b/js/src/tests/lib/tasks_win.py
index 7a4540c60d8c..e8ef467b4a30 100644
--- a/js/src/tests/lib/tasks_win.py
+++ b/js/src/tests/lib/tasks_win.py
@@ -5,12 +5,14 @@ from __future__ import print_function, unicode_literals, division
 
 import subprocess
 import sys
+
 from datetime import datetime, timedelta
-from progressbar import ProgressBar
-from results import NullTestOutput, TestOutput, escape_cmdline
 from threading import Thread
 from Queue import Queue, Empty
 
+from .progressbar import ProgressBar
+from .results import NullTestOutput, TestOutput, escape_cmdline
+
 
 class EndMarker:
     pass
diff --git a/mach b/mach
index babdf5307561..ad227ddad03a 100755
--- a/mach
+++ b/mach
@@ -42,7 +42,6 @@ py2commands="
     ide
     import-pr
     install
-    jit-test
     jsapi-tests
     jsshell-bench
     jstestbrowser
diff --git a/testing/web-platform/manifestdownload.py b/testing/web-platform/manifestdownload.py
index a30be8a39ce6..cccc08177263 100644
--- a/testing/web-platform/manifestdownload.py
+++ b/testing/web-platform/manifestdownload.py
@@ -5,10 +5,15 @@ import os
 from datetime import datetime, timedelta
 import tarfile
 import requests
+import six
 import vcs
-from cStringIO import StringIO
 import logging
 
+try:
+    from cStringIO import StringIO as BytesIO
+except ImportError:
+    from io import BytesIO
+
 HEADERS = {'User-Agent': "wpt manifest download"}
 
 
@@ -117,7 +122,7 @@ def taskcluster_url(logger, commits):
 
 
 def download_manifest(logger, test_paths, commits_func, url_func, force=False):
-    manifest_paths = [item["manifest_path"] for item in test_paths.itervalues()]
+    manifest_paths = [item["manifest_path"] for item in six.itervalues(test_paths)]
 
     if not force and not should_download(logger, manifest_paths):
         return True
@@ -141,8 +146,8 @@ def download_manifest(logger, test_paths, commits_func, url_func, force=False):
                         "HTTP status %d" % req.status_code)
         return False
 
-    tar = tarfile.open(mode="r:gz", fileobj=StringIO(req.content))
-    for paths in test_paths.itervalues():
+    tar = tarfile.open(mode="r:gz", fileobj=BytesIO(req.content))
+    for paths in six.itervalues(test_paths):
         try:
             member = tar.getmember(paths["manifest_rel_path"].replace(os.path.sep, "/"))
         except KeyError:
@@ -151,7 +156,7 @@ def download_manifest(logger, test_paths, commits_func, url_func, force=False):
             try:
                 logger.debug("Unpacking %s to %s" % (member.name, paths["manifest_path"]))
                 src = tar.extractfile(member)
-                with open(paths["manifest_path"], "w") as dest:
+                with open(paths["manifest_path"], "wb") as dest:
                     dest.write(src.read())
                 src.close()
             except IOError:
diff --git a/testing/web-platform/manifestupdate.py b/testing/web-platform/manifestupdate.py
index 4fe70e99fa60..4878fdfbf222 100644
--- a/testing/web-platform/manifestupdate.py
+++ b/testing/web-platform/manifestupdate.py
@@ -6,6 +6,7 @@ import argparse
 import hashlib
 import imp
 import os
+import six
 import sys
 
 from six.moves import configparser
@@ -92,7 +93,7 @@ def run(src_root, obj_root, logger=None, **kwargs):
     test_paths = wptcommandline.get_test_paths(
         wptcommandline.config.read(config_path))
 
-    for paths in test_paths.itervalues():
+    for paths in six.itervalues(test_paths):
         if "manifest_path" not in paths:
             paths["manifest_path"] = os.path.join(paths["metadata_path"],
                                                   "MANIFEST.json")
@@ -125,7 +126,7 @@ def run(src_root, obj_root, logger=None, **kwargs):
 
 
 def ensure_manifest_directories(logger, test_paths):
-    for paths in test_paths.itervalues():
+    for paths in six.itervalues(test_paths):
         manifest_dir = os.path.dirname(paths["manifest_path"])
         if not os.path.exists(manifest_dir):
             logger.info("Creating directory %s" % manifest_dir)
@@ -169,7 +170,7 @@ def generate_config(logger, repo_root, wpt_dir, dest_path, force_rewrite=False):
 
     parser.set('paths', 'prefs', os.path.abspath(os.path.join(wpt_dir, parser.get("paths", "prefs"))))
 
-    with open(dest_config_path, 'wb') as config_file:
+    with open(dest_config_path, 'wt') as config_file:
         parser.write(config_file)
 
     return dest_config_path
@@ -179,7 +180,7 @@ def load_and_update(logger, wpt_dir, test_paths, rebuild=False, config_dir=None,
                     update=True):
     rv = {}
     wptdir_hash = hashlib.sha256(os.path.abspath(wpt_dir)).hexdigest()
-    for url_base, paths in test_paths.iteritems():
+    for url_base, paths in six.iteritems(test_paths):
         manifest_path = paths["manifest_path"]
         this_cache_root = os.path.join(cache_root, wptdir_hash, os.path.dirname(paths["manifest_rel_path"]))
         m = manifest.manifest.load_and_update(paths["tests_path"],