Use mock in a Python 3.4 compatible way

Related to https://code.google.com/p/mock/issues/detail?id=234

Change-Id: I85549fdba7b9cb575850a12d52e1ffb0d2dba8c0

tests/base.py

@@ -27,6 +27,12 @@ import operator
 import testtools
 import xml.etree.ElementTree as XML
 from six.moves import configparser
+# This dance deals with the fact that we want unittest.mock if
+# we're on Python 3.4 and later, and non-stdlib mock otherwise.
+try:
+    from unittest import mock
+except ImportError:
+    import mock  # noqa
 import jenkins_jobs.local_yaml as yaml
 from jenkins_jobs.builder import XmlJob, YamlParser, ModuleRegistry
 from jenkins_jobs.modules import (project_flow,

tests/cachestorage/test_cachestorage.py

@@ -13,10 +13,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
 import testtools
 
 import jenkins_jobs
+from tests.base import mock
 
 
 class TestCaseCacheStorage(testtools.TestCase):

tests/cmd/subcommands/test_delete.py

@@ -1,6 +1,6 @@
 import os
-import mock
 from jenkins_jobs import cmd
+from tests.base import mock
 from tests.cmd.test_cmd import CmdTestsBase
 
 

tests/cmd/subcommands/test_test.py

@@ -1,8 +1,8 @@
 import os
 import io
 import codecs
-import mock
 from jenkins_jobs import cmd
+from tests.base import mock
 from tests.cmd.test_cmd import CmdTestsBase
 
 

tests/cmd/test_cmd.py

@@ -1,8 +1,8 @@
 import os
 from six.moves import configparser, StringIO
-import mock
 import testtools
 from jenkins_jobs import cmd
+from tests.base import mock
 
 
 class CmdTestsBase(testtools.TestCase):

tests/duplicates/test_duplicates.py

@@ -14,11 +14,14 @@
 # under the License.
 
 import os
-import mock
+
 from testtools import TestCase, ExpectedException
 from testscenarios.testcase import TestWithScenarios
-from tests.base import get_scenarios, SingleJobTestCase
+
 from jenkins_jobs.errors import JenkinsJobsException
+from tests.base import SingleJobTestCase
+from tests.base import get_scenarios
+from tests.base import mock
 
 
 class TestCaseModuleDuplicates(TestWithScenarios, TestCase,