cc_landscape & cc_puppet: Fix six.StringIO use in writing configs

Both landscape and puppet modules had issues with the way they wrote
/etc/landscape/client.conf or /etc/puppet/puppet.conf in either python3 or
python2. This branch adds initial unit tests for both modules which will
get better exercise under both python2 and python3.

The unit tests shed light on a few issues:
   - In the cc_landscape module py3 can't provide six.StringIO content to
     ConfigParser.write, so we need to use six.BytesIO instead
   - In the cc_puppet module, python <= 2.7 doesn't support using
     six.StringIO as a context manager, so we drop the context manager
     fanciness and directly set outputstream = StringIO().
   - The docstring in cc_puppet is fixed to document the 'conf'
     sub-key requiring valid puppet section names for each
     key-value list.

LP: #1699282
LP: #1710932

1 files changed, 7 insertions, 7 deletions

diff --git a/cloudinit/helpers.py b/cloudinit/helpers.py
index f01021aa..1979cd96 100644
--- a/cloudinit/helpers.py
+++ b/cloudinit/helpers.py
@@ -13,7 +13,7 @@ from time import time
 import contextlib
 import os
 
-import six
+from six import StringIO
 from six.moves.configparser import (
     NoSectionError, NoOptionError, RawConfigParser)
 
@@ -441,12 +441,12 @@ class DefaultingConfigParser(RawConfigParser):
 
     def stringify(self, header=None):
         contents = ''
-        with six.StringIO() as outputstream:
-            self.write(outputstream)
-            outputstream.flush()
-            contents = outputstream.getvalue()
-            if header:
-                contents = "\n".join([header, contents])
+        outputstream = StringIO()
+        self.write(outputstream)
+        outputstream.flush()
+        contents = outputstream.getvalue()
+        if header:
+            contents = '\n'.join([header, contents, ''])
         return contents
 
 # vi: ts=4 expandtab