Fix guestagent.test_operating_system for Python3

* Tests for _write_file_as_root failed because tempfile.NamedTemporaryFile
  use binary mode by default, changing to text mode fixes.
* Migrate to olso_serialization.base64 for Base64Codec. Also change the
  return value from bytearray to bytes for Base64Codec.deserialize.
  Base64Codec supports reverse encoding(i.e. binary data will be written
  to the dest file), in this situation, the dest file should be opened
  with binary mode(and when reading from the file, binary mode should
  also be used).
* stream_codecs.StringConverter converts iterable objects with map
  function. The behavior of map function is different under Python 2.x
  and 3.x. However csv.writerows(before Python 3.5) and unpack_singleton in
  trove.common.utils both need a list object. Converting the return
  value of map function to a list explicitly before passing to these
  functions fixes.

guestagent.test_operating_system is the last blacklist regex pattern for
py3 unittests. With the above problems fixed, blacklist-py3.txt is not
needed any more, and tox.ini is also updateted.

Migrating from ostestr to stestr is also done while updating tox.ini.
Here is the ML post for more information about os-testr and stestr:

http://lists.openstack.org/pipermail/openstack-dev/2017-September/122135.html

Partially implements: blueprint trove-python3

Change-Id: I31f1f97901d6ebff8a91c1b70a343e724ab806eb
Signed-off-by: Zhao Chao <zhaochao1984@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/.stestr.conf b/.stestr.conf
index f80c78cc..6d13b420 100644
--- a/.stestr.conf
+++ b/.stestr.conf
@@ -1,3 +1,3 @@
 [DEFAULT]
-test_path=${OS_TEST_PATH:-./trove/tests}
-top_dir=./
\ No newline at end of file
+test_path=${OS_TEST_PATH:-./trove/tests/unittests}
+top_dir=./