StringIO compatibility for python3

StringIO can be replaced with six.moves.StringIO which can provide
compatibility for Python 2 and 3. So does cStringIO.

Change-Id: Ieed1e97f1832e56717bc905114eb73fd6c4c4d04

ceilometer/tests/alarm/partition/test_coordination.py

@@ -19,7 +19,7 @@
 """
 import datetime
 import logging
-import StringIO
+import six
 import uuid
 
 import mock
@@ -45,7 +45,7 @@ class TestCoordinate(test.BaseTestCase):
         self.partition_coordinator = coordination.PartitionCoordinator()
         self.partition_coordinator.coordination_rpc = mock.Mock()
         #add extra logger to check exception conditions and logged content
-        self.output = StringIO.StringIO()
+        self.output = six.moves.StringIO()
         self.str_handler = logging.StreamHandler(self.output)
         coordination.LOG.logger.addHandler(self.str_handler)
 

ceilometer/tests/objectstore/test_swift_middleware.py

@@ -17,7 +17,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import cStringIO as StringIO
+import six
 
 import mock
 import webob
@@ -103,7 +103,7 @@ class TestSwiftMiddleware(test.BaseTestCase):
         req = webob.Request.blank('/1.0/account/container/obj',
                                   environ={'REQUEST_METHOD': 'PUT',
                                            'wsgi.input':
-                                           StringIO.StringIO('some stuff')})
+                                           six.moves.cStringIO('some stuff')})
         list(app(req.environ, self.start_response))
         samples = self.pipeline_manager.pipelines[0].samples
         self.assertEqual(len(samples), 2)
@@ -124,7 +124,7 @@ class TestSwiftMiddleware(test.BaseTestCase):
         req = webob.Request.blank(
             '/1.0/account/container/obj',
             environ={'REQUEST_METHOD': 'POST',
-                     'wsgi.input': StringIO.StringIO('some other stuff')})
+                     'wsgi.input': six.moves.cStringIO('some other stuff')})
         list(app(req.environ, self.start_response))
         samples = self.pipeline_manager.pipelines[0].samples
         self.assertEqual(len(samples), 2)