Fix cli.base.execute with py34

In python3, the command must be a string not bytes.

Also all tempest_lib assert tools expected the result is a str.
But in python subprocess stdout/stderr returns bytes
To fix that we decode it with the fsencoding.

Change-Id: Id5b2e5d75f2c881cd2a3fff216126f6529dccef3

tempest_lib/cli/base.py

@@ -16,6 +16,7 @@
 import logging
 import os
 import shlex
+import six
 import subprocess
 
 from tempest_lib import base
@@ -50,7 +51,9 @@ def execute(cmd, action, flags='', params='', fail_ok=False,
     cmd = ' '.join([os.path.join(cli_dir, cmd),
                     flags, action, params])
     LOG.info("running: '%s'" % cmd)
-    cmd = shlex.split(cmd.encode('utf-8'))
+    if six.PY2:
+        cmd = cmd.encode('utf-8')
+    cmd = shlex.split(cmd)
     result = ''
     result_err = ''
     stdout = subprocess.PIPE
@@ -62,7 +65,10 @@ def execute(cmd, action, flags='', params='', fail_ok=False,
                                        cmd,
                                        result,
                                        result_err)
-    return result
+    if six.PY2:
+        return result
+    else:
+        return os.fsdecode(result)
 
 
 class CLIClient(object):

tempest_lib/tests/cli/test_execute.py

@@ -0,0 +1,31 @@
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+from tempest_lib.cli import base as cli_base
+from tempest_lib.tests import base
+
+
+class TestExecute(base.TestCase):
+    def test_execute_success(self):
+        result = cli_base.execute("/bin/ls", action="tempest_lib",
+                                  flags="-l -a")
+        self.assertIsInstance(result, str)
+        self.assertIn("__init__.py", result)
+
+    def test_execute_failure(self):
+        result = cli_base.execute("/bin/ls", action="tempest_lib",
+                                  flags="--foobar", merge_stderr=True,
+                                  fail_ok=True)
+        self.assertIsInstance(result, str)
+        self.assertIn("--foobar", result)