diff --git a/gerrit_client.py b/gerrit_client.py
index 8ea4df4d1..9bda02556 100755
--- a/gerrit_client.py
+++ b/gerrit_client.py
@@ -9,12 +9,20 @@ Example usage:
   ./gerrit_client.py [command] [args]
 """
 
+from __future__ import print_function
+
 import json
 import logging
 import optparse
 import subcommand
 import sys
-import urllib.parse
+
+if sys.version_info.major == 2:
+  import urlparse
+  from urllib import quote_plus
+else:
+  from urllib.parse import quote_plus
+  import urllib.parse as urlparse
 
 import fix_encoding
 import gerrit_util
@@ -41,7 +49,7 @@ def CMDmovechanges(parser, args):
   assert opt.destination_branch, "--destination_branch not defined"
   for p in opt.params:
     assert '=' in p, '--param is key=value, not "%s"' % p
-  host = urllib.parse.urlparse(opt.host).netloc
+  host = urlparse.urlparse(opt.host).netloc
 
   limit = 100
   while True:
@@ -64,9 +72,9 @@ def CMDbranchinfo(parser, args):
   parser.add_option('--branch', dest='branch', help='branch name')
 
   (opt, args) = parser.parse_args(args)
-  host = urllib.parse.urlparse(opt.host).netloc
-  project = urllib.parse.quote_plus(opt.project)
-  branch = urllib.parse.quote_plus(opt.branch)
+  host = urlparse.urlparse(opt.host).netloc
+  project = quote_plus(opt.project)
+  branch = quote_plus(opt.branch)
   result = gerrit_util.GetGerritBranch(host, project, branch)
   logging.info(result)
   write_result(result, opt)
@@ -86,7 +94,7 @@ def CMDrawapi(parser, args):
   (opt, args) = parser.parse_args(args)
   assert opt.path, "--path not defined"
 
-  host = urllib.parse.urlparse(opt.host).netloc
+  host = urlparse.urlparse(opt.host).netloc
   kwargs = {}
   if opt.method:
     kwargs['reqtype'] = opt.method.upper()
@@ -114,9 +122,9 @@ def CMDbranch(parser, args):
   assert opt.branch, "--branch not defined"
   assert opt.commit, "--commit not defined"
 
-  project = urllib.parse.quote_plus(opt.project)
-  host = urllib.parse.urlparse(opt.host).netloc
-  branch = urllib.parse.quote_plus(opt.branch)
+  project = quote_plus(opt.project)
+  host = urlparse.urlparse(opt.host).netloc
+  branch = quote_plus(opt.branch)
   result = gerrit_util.GetGerritBranch(host, project, branch)
   if result:
     if not opt.allow_existent_branch:
@@ -153,9 +161,9 @@ def CMDtag(parser, args):
   assert opt.tag, "--tag not defined"
   assert opt.commit, "--commit not defined"
 
-  project = urllib.parse.quote_plus(opt.project)
-  host = urllib.parse.urlparse(opt.host).netloc
-  tag = urllib.parse.quote_plus(opt.tag)
+  project = quote_plus(opt.project)
+  host = urlparse.urlparse(opt.host).netloc
+  tag = quote_plus(opt.tag)
   result = gerrit_util.CreateGerritTag(host, project, tag, opt.commit)
   logging.info(result)
   write_result(result, opt)
@@ -170,9 +178,9 @@ def CMDhead(parser, args):
   assert opt.project, "--project not defined"
   assert opt.branch, "--branch not defined"
 
-  project = urllib.parse.quote_plus(opt.project)
-  host = urllib.parse.urlparse(opt.host).netloc
-  branch = urllib.parse.quote_plus(opt.branch)
+  project = quote_plus(opt.project)
+  host = urlparse.urlparse(opt.host).netloc
+  branch = quote_plus(opt.branch)
   result = gerrit_util.UpdateHead(host, project, branch)
   logging.info(result)
   write_result(result, opt)
@@ -185,8 +193,8 @@ def CMDheadinfo(parser, args):
   (opt, args) = parser.parse_args(args)
   assert opt.project, "--project not defined"
 
-  project = urllib.parse.quote_plus(opt.project)
-  host = urllib.parse.urlparse(opt.host).netloc
+  project = quote_plus(opt.project)
+  host = urlparse.urlparse(opt.host).netloc
   result = gerrit_util.GetHead(host, project)
   logging.info(result)
   write_result(result, opt)
@@ -216,7 +224,7 @@ def CMDchanges(parser, args):
     assert '=' in p, '--param is key=value, not "%s"' % p
 
   result = gerrit_util.QueryChanges(
-      urllib.parse.urlparse(opt.host).netloc,
+      urlparse.urlparse(opt.host).netloc,
       list(tuple(p.split('=', 1)) for p in opt.params),
       first_param=opt.query,
       start=opt.start,  # Default: None
@@ -236,7 +244,7 @@ def CMDrelatedchanges(parser, args):
   (opt, args) = parser.parse_args(args)
 
   result = gerrit_util.GetRelatedChanges(
-      urllib.parse.urlparse(opt.host).netloc,
+      urlparse.urlparse(opt.host).netloc,
       change=opt.change,
       revision=opt.revision,
   )
@@ -274,7 +282,7 @@ def CMDcreatechange(parser, args):
     params.append(('notify_details', {'CC': {'accounts': opt.cc_list}}))
 
   result = gerrit_util.CreateChange(
-      urllib.parse.urlparse(opt.host).netloc,
+      urlparse.urlparse(opt.host).netloc,
       opt.project,
       branch=opt.branch,
       subject=opt.subject,
@@ -296,7 +304,7 @@ def CMDchangeedit(parser, args):
   with open(opt.file) as f:
     data = f.read()
   result = gerrit_util.ChangeEdit(
-      urllib.parse.urlparse(opt.host).netloc, opt.change, opt.path, data)
+      urlparse.urlparse(opt.host).netloc, opt.change, opt.path, data)
   logging.info(result)
   write_result(result, opt)
 
@@ -310,7 +318,7 @@ def CMDpublishchangeedit(parser, args):
   (opt, args) = parser.parse_args(args)
 
   result = gerrit_util.PublishChangeEdit(
-      urllib.parse.urlparse(opt.host).netloc, opt.change, opt.notify)
+      urlparse.urlparse(opt.host).netloc, opt.change, opt.notify)
   logging.info(result)
   write_result(result, opt)
 
@@ -321,7 +329,7 @@ def CMDsubmitchange(parser, args):
   parser.add_option('-c', '--change', type=int, help='change number')
   (opt, args) = parser.parse_args(args)
   result = gerrit_util.SubmitChange(
-      urllib.parse.urlparse(opt.host).netloc, opt.change)
+      urlparse.urlparse(opt.host).netloc, opt.change)
   logging.info(result)
   write_result(result, opt)
 
@@ -332,7 +340,7 @@ def CMDchangesubmittedtogether(parser, args):
   parser.add_option('-c', '--change', type=int, help='change number')
   (opt, args) = parser.parse_args(args)
   result = gerrit_util.GetChangesSubmittedTogether(
-      urllib.parse.urlparse(opt.host).netloc, opt.change)
+      urlparse.urlparse(opt.host).netloc, opt.change)
   logging.info(result)
   write_result(result, opt)
 
@@ -343,7 +351,7 @@ def CMDgetcommitincludedin(parser, args):
   parser.add_option('--commit', dest='commit', help='commit hash')
   (opt, args) = parser.parse_args(args)
   result = gerrit_util.GetCommitIncludedIn(
-      urllib.parse.urlparse(opt.host).netloc, opt.project, opt.commit)
+      urlparse.urlparse(opt.host).netloc, opt.project, opt.commit)
   logging.info(result)
   write_result(result, opt)
 
@@ -353,10 +361,11 @@ def CMDsetbotcommit(parser, args):
   """Sets bot-commit+1 to a bot generated change."""
   parser.add_option('-c', '--change', type=int, help='change number')
   (opt, args) = parser.parse_args(args)
-  result = gerrit_util.SetReview(urllib.parse.urlparse(opt.host).netloc,
-                                 opt.change,
-                                 labels={'Bot-Commit': 1},
-                                 ready=True)
+  result = gerrit_util.SetReview(
+      urlparse.urlparse(opt.host).netloc,
+      opt.change,
+      labels={'Bot-Commit': 1},
+      ready=True)
   logging.info(result)
   write_result(result, opt)
 
@@ -370,7 +379,7 @@ def CMDsetlabel(parser, args):
                     nargs=2,
                     metavar=('label_name', 'label_value'))
   (opt, args) = parser.parse_args(args)
-  result = gerrit_util.SetReview(urllib.parse.urlparse(opt.host).netloc,
+  result = gerrit_util.SetReview(urlparse.urlparse(opt.host).netloc,
                                  opt.change,
                                  labels={opt.label[0]: opt.label[1]})
   logging.info(result)
@@ -386,7 +395,8 @@ def CMDabandon(parser, args):
   (opt, args) = parser.parse_args(args)
   assert opt.change, "-c not defined"
   result = gerrit_util.AbandonChange(
-      urllib.parse.urlparse(opt.host).netloc, opt.change, opt.message)
+      urlparse.urlparse(opt.host).netloc,
+      opt.change, opt.message)
   logging.info(result)
   write_result(result, opt)
 
@@ -429,7 +439,7 @@ def CMDmass_abandon(parser, args):
   search_query.append(('status', 'open'))
   logging.info("Searching for: %s" % search_query)
 
-  host = urllib.parse.urlparse(opt.host).netloc
+  host = urlparse.urlparse(opt.host).netloc
 
   result = gerrit_util.QueryChanges(
       host,
diff --git a/gerrit_util.py b/gerrit_util.py
index 1aeb94c51..8312bbac7 100644
--- a/gerrit_util.py
+++ b/gerrit_util.py
@@ -8,6 +8,9 @@ Utilities for requesting information for a Gerrit server via HTTPS.
 https://gerrit-review.googlesource.com/Documentation/rest-api.html
 """
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import base64
 import contextlib
 import httplib2
@@ -30,10 +33,15 @@ import metrics
 import metrics_utils
 import subprocess2
 
+from third_party import six
 from six.moves import urllib
 
-import http.cookiejar
-from io import StringIO
+if sys.version_info.major == 2:
+  import cookielib
+  from StringIO import StringIO
+else:
+  import http.cookiejar as cookielib
+  from io import StringIO
 
 LOGGER = logging.getLogger()
 # With a starting sleep time of 12.0 seconds, x <= [1.8-2.2]x backoff, and six
@@ -247,7 +255,7 @@ class CookiesAuthenticator(Authenticator):
 
   def _get_auth_for_host(self, host):
     for domain, creds in self.gitcookies.items():
-      if http.cookiejar.domain_match(host, domain):
+      if cookielib.domain_match(host, domain):
         return (creds[0], None, creds[1])
     return self.netrc.authenticators(host)
 
diff --git a/git_cache.py b/git_cache.py
index cd67f24f8..6c4609c61 100755
--- a/git_cache.py
+++ b/git_cache.py
@@ -5,7 +5,10 @@
 
 """A git command for managing a local cache of git repositories."""
 
+from __future__ import print_function
+
 import contextlib
+import errno
 import logging
 import optparse
 import os
@@ -15,7 +18,11 @@ import sys
 import tempfile
 import threading
 import time
-import urllib.parse
+
+try:
+  import urlparse
+except ImportError:  # For Py3 compatibility
+  import urllib.parse as urlparse
 
 from download_from_google_storage import Gsutil
 import gclient_utils
@@ -135,7 +142,7 @@ class Mirror(object):
     b = os.getenv('OVERRIDE_BOOTSTRAP_BUCKET')
     if b:
       return b
-    u = urllib.parse.urlparse(self.url)
+    u = urlparse.urlparse(self.url)
     if u.netloc == 'chromium.googlesource.com':
       return 'chromium-git-cache'
     # Not recognized.
@@ -157,7 +164,7 @@ class Mirror(object):
       url = os.path.splitdrive(url)[1]
       return url.replace('-', '--').replace(os.sep, '-')
 
-    parsed = urllib.parse.urlparse(url)
+    parsed = urlparse.urlparse(url)
     norm_url = parsed.netloc + parsed.path
     if norm_url.endswith('.git'):
       norm_url = norm_url[:-len('.git')]
@@ -352,7 +359,7 @@ class Mirror(object):
 
   def supported_project(self):
     """Returns true if this repo is known to have a bootstrap zip file."""
-    u = urllib.parse.urlparse(self.url)
+    u = urlparse.urlparse(self.url)
     return u.netloc in [
         'chromium.googlesource.com',
         'chrome-internal.googlesource.com']
diff --git a/git_cl.py b/git_cl.py
index 352bf8a72..b0f7efbb0 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -7,6 +7,8 @@
 
 """A git-command for integrating reviews on Gerrit."""
 
+from __future__ import print_function
+
 import base64
 import collections
 import datetime
@@ -53,9 +55,14 @@ import subprocess2
 import swift_format
 import watchlists
 
+from third_party import six
 from six.moves import urllib
 
 
+if sys.version_info.major == 3:
+  basestring = (str,)  # pylint: disable=redefined-builtin
+
+
 __version__ = '2.0'
 
 # Traces for git push will be stored in a traces directory inside the
@@ -915,7 +922,7 @@ def ParseIssueNumberArgument(arg):
 
   if isinstance(arg, int):
     return _ParsedIssueNumberArgument(issue=arg)
-  if not isinstance(arg, str):
+  if not isinstance(arg, basestring):
     return fail_result
 
   if arg.isdigit():
@@ -3172,7 +3179,7 @@ class ChangeDescription(object):
     return '\n'.join(self._description_lines)
 
   def set_description(self, desc):
-    if isinstance(desc, str):
+    if isinstance(desc, basestring):
       lines = desc.splitlines()
     else:
       lines = [line.rstrip() for line in desc]
diff --git a/git_common.py b/git_common.py
index 8ba938dba..4add1782b 100644
--- a/git_common.py
+++ b/git_common.py
@@ -13,7 +13,9 @@ from multiprocessing.pool import IMapIterator
 
 def wrapper(func):
   def wrap(self, timeout=None):
-    return func(self, timeout=timeout or threading.TIMEOUT_MAX)
+    default_timeout = (1 << 31 if sys.version_info.major == 2 else
+                       threading.TIMEOUT_MAX)
+    return func(self, timeout=timeout or default_timeout)
 
   return wrap
 IMapIterator.next = wrapper(IMapIterator.next)
diff --git a/git_drover.py b/git_drover.py
index 7fb089763..524d967b7 100755
--- a/git_drover.py
+++ b/git_drover.py
@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import print_function
+
 import argparse
 
 
diff --git a/git_find_releases.py b/git_find_releases.py
index 64de921bd..770cc01d4 100755
--- a/git_find_releases.py
+++ b/git_find_releases.py
@@ -11,6 +11,8 @@ Note that it uses the "cherry picked from" annotation to find merges, so it will
 only work on merges that followed the "use cherry-pick -x" instructions.
 """
 
+from __future__ import print_function
+
 import optparse
 import re
 import sys
diff --git a/git_footers.py b/git_footers.py
index b8c1db7d8..88149c982 100755
--- a/git_footers.py
+++ b/git_footers.py
@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import print_function
+
 import argparse
 import json
 import re
diff --git a/git_hyper_blame.py b/git_hyper_blame.py
index 560a3bf34..1b63a3b20 100755
--- a/git_hyper_blame.py
+++ b/git_hyper_blame.py
@@ -6,6 +6,9 @@
 """Wrapper around git blame that ignores certain commits.
 """
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import argparse
 import collections
 import logging
diff --git a/git_map.py b/git_map.py
index e693fbece..10b321bfb 100755
--- a/git_map.py
+++ b/git_map.py
@@ -17,6 +17,8 @@ point to them. Items are colorized as follows:
   * Blue background - The currently checked out commit
 """
 
+from __future__ import unicode_literals
+
 import os
 import sys
 
@@ -27,6 +29,12 @@ import subprocess2
 from third_party import colorama
 
 
+if sys.version_info.major == 2:
+  # On Python 3, BrokenPipeError is raised instead.
+  # pylint:disable=redefined-builtin
+  BrokenPipeError = IOError
+
+
 RESET = colorama.Fore.RESET + colorama.Back.RESET + colorama.Style.RESET_ALL
 BRIGHT = colorama.Style.BRIGHT
 
diff --git a/git_map_branches.py b/git_map_branches.py
index 53a195a19..d06a4ceb9 100755
--- a/git_map_branches.py
+++ b/git_map_branches.py
@@ -24,6 +24,8 @@ Branches are colorized as follows:
     upstream, then you will see this.
 """
 
+from __future__ import print_function
+
 import argparse
 import collections
 import metrics
diff --git a/git_mark_merge_base.py b/git_mark_merge_base.py
index 2a45bae13..35ae5eebb 100755
--- a/git_mark_merge_base.py
+++ b/git_mark_merge_base.py
@@ -11,6 +11,8 @@ purposes of the chromium depot_tools git extensions. Passing no arguments will
 just print the effective merge base for the current branch.
 """
 
+from __future__ import print_function
+
 import argparse
 import sys
 
diff --git a/git_nav_downstream.py b/git_nav_downstream.py
index a378707a6..a77d9a2a7 100755
--- a/git_nav_downstream.py
+++ b/git_nav_downstream.py
@@ -9,6 +9,8 @@ is more than one downstream branch, then this script will prompt you to select
 which branch.
 """
 
+from __future__ import print_function
+
 import argparse
 import sys
 
diff --git a/git_number.py b/git_number.py
index 864f3ee8c..f46b1eeb6 100755
--- a/git_number.py
+++ b/git_number.py
@@ -21,6 +21,9 @@ commit's entire history, this script caches all calculated data inside the git
 repo that it operates on in the ref 'refs/number/commits'.
 """
 
+from __future__ import print_function
+from __future__ import division
+
 import binascii
 import collections
 import logging
@@ -57,7 +60,10 @@ def pathlify(hash_prefix):
   >>> pathlify('\xDE\xAD')
   'de/ad'
   """
-  return '/'.join('%02x' % b for b in hash_prefix)
+  if sys.version_info.major == 3:
+    return '/'.join('%02x' % b for b in hash_prefix)
+
+  return '/'.join('%02x' % ord(b) for b in hash_prefix)
 
 
 @git.memoize_one(threadsafe=False)
@@ -178,7 +184,10 @@ def preload_tree(prefix):
 
 
 def all_prefixes(depth=PREFIX_LEN):
-  prefixes = [bytes([i]) for i in range(255)]
+  if sys.version_info.major == 3:
+    prefixes = [bytes([i]) for i in range(255)]
+  else:
+    prefixes = [chr(i) for i in range(255)]
   for x in prefixes:
     # This isn't covered because PREFIX_LEN currently == 1
     if depth > 1:  # pragma: no cover
diff --git a/git_rebase_update.py b/git_rebase_update.py
index 9c9881ab6..c7bae67f3 100755
--- a/git_rebase_update.py
+++ b/git_rebase_update.py
@@ -7,6 +7,8 @@
 Tool to update all branches to have the latest changes from their upstreams.
 """
 
+from __future__ import print_function
+
 import argparse
 import collections
 import logging
diff --git a/git_reparent_branch.py b/git_reparent_branch.py
index e84fdd74f..9180f6035 100755
--- a/git_reparent_branch.py
+++ b/git_reparent_branch.py
@@ -5,6 +5,8 @@
 
 """Change the upstream of the current branch."""
 
+from __future__ import print_function
+
 import argparse
 import sys
 
diff --git a/git_upstream_diff.py b/git_upstream_diff.py
index 4fd9da5cc..f1e712ea8 100755
--- a/git_upstream_diff.py
+++ b/git_upstream_diff.py
@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import print_function
+
 import argparse
 import sys
 
diff --git a/testing_support/git_test_utils.py b/testing_support/git_test_utils.py
index 2a7a9c22d..1b9f655fa 100644
--- a/testing_support/git_test_utils.py
+++ b/testing_support/git_test_utils.py
@@ -20,6 +20,10 @@ import gclient_utils
 
 DEFAULT_BRANCH = 'main'
 
+if sys.version_info.major == 3:
+  # pylint: disable=redefined-builtin
+  basestring = (str,)
+
 
 def git_hash_data(data, typ='blob'):
   """Calculate the git-style SHA1 for some data.
@@ -329,7 +333,7 @@ class GitRepo(object):
 
     for fname, file_data in commit_data.items():
       # If it isn't a string, it's one of the special keys.
-      if not isinstance(fname, str):
+      if not isinstance(fname, basestring):
         continue
 
       deleted = False
@@ -492,6 +496,8 @@ class GitRepoSchemaTestBase(unittest.TestCase):
   @classmethod
   def getRepoContent(cls, commit):
     commit = 'COMMIT_%s' % commit
+    if sys.version_info.major == 2:
+      commit = commit.encode('utf-8')
     return getattr(cls, commit, None)
 
   @classmethod
diff --git a/tests/gerrit_client_test.py b/tests/gerrit_client_test.py
index c4375929e..4ad4a2b2e 100755
--- a/tests/gerrit_client_test.py
+++ b/tests/gerrit_client_test.py
@@ -9,11 +9,20 @@ import logging
 import os
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+  BUILTIN_OPEN = '__builtin__.open'
+else:
+  from io import StringIO
+  from unittest import mock
+  BUILTIN_OPEN = 'builtins.open'
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import gerrit_client
+import gerrit_util
 
 
 class TestGerritClient(unittest.TestCase):
@@ -111,7 +120,7 @@ class TestGerritClient(unittest.TestCase):
                                       subject='subject',
                                       params=[('work_in_progress', 'true')])
 
-  @mock.patch('builtins.open', mock.mock_open())
+  @mock.patch(BUILTIN_OPEN, mock.mock_open())
   @mock.patch('gerrit_util.ChangeEdit', return_value='')
   def test_changeedit(self, util_mock):
     open().read.return_value = 'test_data'
diff --git a/tests/gerrit_util_test.py b/tests/gerrit_util_test.py
index 59d427d31..4eda84aa8 100755
--- a/tests/gerrit_util_test.py
+++ b/tests/gerrit_util_test.py
@@ -4,19 +4,31 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
+
+import base64
 import httplib2
-from io import StringIO
 import json
 import os
 import socket
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from cStringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import gerrit_util
+import gclient_utils
 import metrics
+import metrics_utils
 import subprocess2
 
 
diff --git a/tests/git_cache_test.py b/tests/git_cache_test.py
index 43278d66b..a85231e2a 100755
--- a/tests/git_cache_test.py
+++ b/tests/git_cache_test.py
@@ -5,7 +5,6 @@
 
 """Unit tests for git_cache.py"""
 
-from io import StringIO
 import logging
 import os
 import shutil
@@ -13,7 +12,13 @@ import subprocess
 import sys
 import tempfile
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 DEPOT_TOOLS_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, DEPOT_TOOLS_ROOT)
diff --git a/tests/git_cl_test.py b/tests/git_cl_test.py
index 0262afc40..c8304f76e 100755
--- a/tests/git_cl_test.py
+++ b/tests/git_cl_test.py
@@ -6,18 +6,27 @@
 
 """Unit tests for git_cl.py."""
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import datetime
 import json
 import logging
-from io import StringIO
 import multiprocessing
 import optparse
 import os
+import pprint
 import shutil
 import sys
 import tempfile
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/git_common_test.py b/tests/git_common_test.py
index 3c001b5bc..3d4d60ac8 100755
--- a/tests/git_common_test.py
+++ b/tests/git_common_test.py
@@ -6,6 +6,9 @@
 
 """Unit tests for git_common.py"""
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import binascii
 import collections
 import datetime
diff --git a/tests/git_find_releases_test.py b/tests/git_find_releases_test.py
index 5db8c5d3d..d4d9490da 100755
--- a/tests/git_find_releases_test.py
+++ b/tests/git_find_releases_test.py
@@ -5,16 +5,25 @@
 # found in the LICENSE file.
 """Unit tests for git_find_releases.py."""
 
-from io import StringIO
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import logging
 import os
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import git_find_releases
+import git_common
 
 
 class TestGitFindReleases(unittest.TestCase):
diff --git a/tests/git_footers_test.py b/tests/git_footers_test.py
index de73cadd5..a67537e37 100755
--- a/tests/git_footers_test.py
+++ b/tests/git_footers_test.py
@@ -2,12 +2,18 @@
 
 """Tests for git_footers."""
 
-from io import StringIO
 import json
 import os
 import sys
+import tempfile
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/git_hyper_blame_test.py b/tests/git_hyper_blame_test.py
index edc5038cf..419930887 100755
--- a/tests/git_hyper_blame_test.py
+++ b/tests/git_hyper_blame_test.py
@@ -4,13 +4,23 @@
 # found in the LICENSE file.
 """Tests for git_dates."""
 
-from io import BytesIO, StringIO
+from __future__ import unicode_literals
+
+import datetime
 import os
 import re
 import shutil
 import sys
 import tempfile
-from unittest import mock
+import unittest
+
+from io import BytesIO
+if sys.version_info.major == 2:
+  from StringIO import StringIO
+  import mock
+else:
+  from io import StringIO
+  from unittest import mock
 
 DEPOT_TOOLS_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, DEPOT_TOOLS_ROOT)
@@ -19,6 +29,7 @@ from testing_support import coverage_utils
 from testing_support import git_test_utils
 
 import gclient_utils
+import git_common
 
 GitRepo = git_test_utils.GitRepo
 
@@ -579,7 +590,11 @@ class GitHyperBlameUnicodeTest(GitHyperBlameTestBase):
 
   # Add a line.
   COMMIT_B = {
-      GitRepo.AUTHOR_NAME: '\u4e2d\u56fd\u4f5c\u8005',
+      # AUTHOR_NAME has .encode('utf-8') for py2 as Windows raises exception
+      # otherwise. Type remains str
+      GitRepo.AUTHOR_NAME:
+      ('\u4e2d\u56fd\u4f5c\u8005'.encode('utf-8')
+       if sys.version_info.major == 2 else '\u4e2d\u56fd\u4f5c\u8005'),
       'file': {
           'data': b'red\ngreen\nblue\n'
       },
@@ -587,12 +602,40 @@ class GitHyperBlameUnicodeTest(GitHyperBlameTestBase):
 
   # Modify a line with non-UTF-8 author and file text.
   COMMIT_C = {
-      GitRepo.AUTHOR_NAME: 'Lat\xedn-1 Author',
+      GitRepo.AUTHOR_NAME:
+      ('Lat\u00edn-1 Author'.encode('latin-1')
+       if sys.version_info.major == 2 else 'Lat\xedn-1 Author'),
       'file': {
           'data': 'red\ngre\u00e9n\nblue\n'.encode('latin-1')
       },
   }
 
+  @unittest.skipIf(
+      sys.platform.startswith("win") and sys.version_info.major == 2,
+      "Known issue for Windows and py2")
+  def testNonASCIIAuthorName(self):
+    """Ensures correct tabulation.
+
+    Tests the case where there are non-ASCII (UTF-8) characters in the author
+    name.
+
+    Regression test for https://crbug.com/808905.
+
+    This test is disabled only for Windows and Python2 as `author` gets escaped
+    differently.
+    """
+    # Known issue with Windows and py2, skip test for such env
+    expected_output = [
+        self.blame_line('A', '1) red', author='ASCII Author'),
+        # Expect 8 spaces, to line up with the other name.
+        self.blame_line(
+            'B', '2) green', author='\u4e2d\u56fd\u4f5c\u8005        '),
+        self.blame_line('A', '3) blue', author='ASCII Author'),
+    ]
+    retval, output = self.run_hyperblame([], 'file', 'tag_B')
+    self.assertEqual(0, retval)
+    self.assertEqual(expected_output, output)
+
   def testNonUTF8Data(self):
     """Ensures correct behaviour even if author or file data is not UTF-8.
 
diff --git a/tests/git_map_test.py b/tests/git_map_test.py
index ecb272eaa..60d44f512 100644
--- a/tests/git_map_test.py
+++ b/tests/git_map_test.py
@@ -5,12 +5,14 @@
 # found in the LICENSE file.
 """Tests for git_map."""
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import io
 import os
 import re
 import sys
 import unittest
-from unittest import mock
 
 DEPOT_TOOLS_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, DEPOT_TOOLS_ROOT)
@@ -20,6 +22,11 @@ from testing_support import git_test_utils
 import git_map
 import git_common
 
+if sys.version_info.major == 2:
+  import mock
+else:
+  from unittest import mock
+
 
 git_common.TEST_MODE = True
 GitRepo = git_test_utils.GitRepo
@@ -104,7 +111,7 @@ class GitMapTest(git_test_utils.GitRepoReadOnlyTestBase):
         '* 315457dbe8	(tag_B) 1970-01-04 ~ B',
         '* cd589e62d8	(tag_A, origin/root_A) 1970-01-02 ~ A',
         '* 7026d3d68e	(tag_", root_", main, branch_") 1970-01-02 ~ "',
-    ])
+		])
     outbuf = io.BytesIO()
     self.repo.run(git_map.main, [], outbuf)
     output = outbuf.getvalue()
diff --git a/tests/git_migrate_default_branch_test.py b/tests/git_migrate_default_branch_test.py
index 8f227e53b..977713bda 100755
--- a/tests/git_migrate_default_branch_test.py
+++ b/tests/git_migrate_default_branch_test.py
@@ -8,7 +8,11 @@ import collections
 import os
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  import mock
+else:
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
diff --git a/tests/git_rebase_update_test.py b/tests/git_rebase_update_test.py
index 492c2e076..dd4276121 100755
--- a/tests/git_rebase_update_test.py
+++ b/tests/git_rebase_update_test.py
@@ -5,6 +5,9 @@
 
 """Unit tests for git_rebase_update.py"""
 
+from __future__ import print_function
+from __future__ import unicode_literals
+
 import os
 import sys
 
diff --git a/tests/owners_client_test.py b/tests/owners_client_test.py
index 22ebfdb6f..3e69c7697 100755
--- a/tests/owners_client_test.py
+++ b/tests/owners_client_test.py
@@ -6,13 +6,19 @@
 import os
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  import mock
+else:
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 import gerrit_util
 import owners_client
 
+from testing_support import filesystem_mock
+
 
 alice = 'alice@example.com'
 bob = 'bob@example.com'
diff --git a/tests/owners_finder_test.py b/tests/owners_finder_test.py
index 0f43716ba..56955954f 100755
--- a/tests/owners_finder_test.py
+++ b/tests/owners_finder_test.py
@@ -8,7 +8,11 @@
 import os
 import sys
 import unittest
-from unittest import mock
+
+if sys.version_info.major == 2:
+  import mock
+else:
+  from unittest import mock
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))