Make TimezoneMixin importable on Python 3.

src/allmydata/test/common_util.py

@@ -185,31 +185,6 @@ class TestMixin(SignalMixin):
             self.fail("Reactor was still active when it was required to be quiescent.")
 
 
-class TimezoneMixin(object):
-
-    def setTimezone(self, timezone):
-        def tzset_if_possible():
-            # Windows doesn't have time.tzset().
-            if hasattr(time, 'tzset'):
-                time.tzset()
-
-        unset = object()
-        originalTimezone = os.environ.get('TZ', unset)
-        def restoreTimezone():
-            if originalTimezone is unset:
-                del os.environ['TZ']
-            else:
-                os.environ['TZ'] = originalTimezone
-            tzset_if_possible()
-
-        os.environ['TZ'] = timezone
-        self.addCleanup(restoreTimezone)
-        tzset_if_possible()
-
-    def have_working_tzset(self):
-        return hasattr(time, 'tzset')
-
-
 try:
     import win32file
     import win32con

src/allmydata/test/test_time_format.py

@@ -6,7 +6,7 @@ import time
 
 from twisted.trial import unittest
 
-from allmydata.test.common_util import TimezoneMixin
+from allmydata.test.common_py3 import TimezoneMixin
 from allmydata.util import time_format
 
 

src/allmydata/test/test_util.py

@@ -21,7 +21,7 @@ from allmydata.util import statistics, dictutil, pipeline, yamlutil
 from allmydata.util import log as tahoe_log
 from allmydata.util.spans import Spans, overlap, DataSpans
 from allmydata.util.fileutil import EncryptedTemporaryFile
-from allmydata.test.common_util import ReallyEqualMixin, TimezoneMixin
+from allmydata.test.common_util import ReallyEqualMixin
 
 if six.PY3:
     long = int

src/allmydata/test/web/test_web.py

@@ -60,6 +60,7 @@ from .common import (
 from allmydata.interfaces import IMutableFileNode, SDMF_VERSION, MDMF_VERSION
 from allmydata.mutable import servermap, publish, retrieve
 from .. import common_util as testutil
+from ..common_py3 import TimezoneMixin
 from ..common_web import (
     do_http,
     Error,
@@ -311,7 +312,7 @@ class FakeClient(_Client):
 
     MUTABLE_SIZELIMIT = FakeMutableFileNode.MUTABLE_SIZELIMIT
 
-class WebMixin(testutil.TimezoneMixin):
+class WebMixin(TimezoneMixin):
     def setUp(self):
         self.setTimezone('UTC-13:00')
         self.s = FakeClient()

src/allmydata/util/_python3.py

@@ -22,6 +22,7 @@ PORTED_MODULES = [
     "allmydata.util.namespace",
     "allmydata.util.pollmixin",
     "allmydata.util._python3",
+    "allmydata.test.common_py3",
 ]
 
 PORTED_TEST_MODULES = [