Python 3: fix glance.tests.functional.db.simple

We need to avoid comparing None to another type, as the comparison will be
invalid on Python 3.

Change-Id: I2beee405c17e2c6cdd6198b9d089e806a9c56c70

glance/db/simple/api.py

@@ -16,7 +16,6 @@
 
 import copy
 import functools
-from operator import itemgetter
 import uuid
 
 from oslo_log import log as logging
@@ -382,7 +381,7 @@ def _sort_images(images, sort_key, sort_dir):
 
     for key, dir in reversed(list(zip(sort_key, sort_dir))):
         reverse = dir == 'desc'
-        images.sort(key=itemgetter(key), reverse=reverse)
+        images.sort(key=lambda x: x[key] or '', reverse=reverse)
 
     return images
 

tox.ini

@@ -21,7 +21,10 @@ install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstac
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:py34]
-commands = lockutils-wrapper python setup.py testr --slowest --testr-args='glance.tests.unit'
+commands =
+  lockutils-wrapper python setup.py testr --slowest --testr-args='glance.tests.unit'
+  python -m testtools.run \
+    glance.tests.functional.db.test_simple
 
 [testenv:py34-constraints]
 install_command = {[testenv:common-constraints]install_command}