avocado/utils/process.py: add cmd_split() function

Signed-off-by: NCleber Rosa <crosa@redhat.com>

avocado/utils/process.py

@@ -34,6 +34,7 @@ import time
 from io import BytesIO, UnsupportedOperation
 from six import PY2, string_types
 
+from . import astring
 from . import gdb
 from . import runtime
 from . import path
@@ -281,6 +282,26 @@ def binary_from_shell_cmd(cmd, encoding=None):
     raise ValueError("Unable to parse first binary from '%s'" % cmd)
 
 
+def cmd_split(cmd):
+    """
+    Splits a command line into individual components
+
+    This is a simple wrapper around :func:`shlex.split`, which has the
+    requirement of having text (not bytes) as its argument on Python 3,
+    but bytes on Python 2.
+
+    :param cmd: text (a multi byte string) encoded as 'utf-8'
+    """
+    if sys.version_info[0] < 3:
+        data = cmd.encode('utf-8')
+        result = shlex.split(data)
+        result = [i.decode('utf-8') for i in result]
+    else:
+        data = astring.to_text(cmd, 'utf-8')
+        result = shlex.split(data)
+    return result
+
+
 class CmdResult(object):
 
     """

selftests/unit/test_utils_process.py

 import io
 import logging
 import os
+import shlex
 import unittest
 
 try:
@@ -9,6 +10,7 @@ except ImportError:
     import mock
 
 
+from avocado.utils import astring
 from avocado.utils import gdb
 from avocado.utils import process
 from avocado.utils import path
@@ -285,6 +287,32 @@ class MiscProcessTests(unittest.TestCase):
         res = process.binary_from_shell_cmd("FOO=bar ./bin var=value")
         self.assertEqual("./bin", res)
 
+    def test_cmd_split(self):
+        plain_str = ''
+        unicode_str = u''
+        empty_bytes = b''
+        # shlex.split() can work with "plain_str" and "unicode_str" on both
+        # Python 2 and Python 3.  While we're not testing Python itself,
+        # this will help us catch possible differences in the Python
+        # standard library should they arise.
+        self.assertEqual(shlex.split(plain_str), [])
+        self.assertEqual(shlex.split(astring.to_text(plain_str)), [])
+        self.assertEqual(shlex.split(unicode_str), [])
+        self.assertEqual(shlex.split(astring.to_text(unicode_str)), [])
+        # on Python 3, shlex.split() won't work with bytes, raising:
+        # AttributeError: 'bytes' object has no attribute 'read'.
+        # To turn bytes into text (when necessary), that is, on
+        # Python 3 only, use astring.to_text()
+        self.assertEqual(shlex.split(astring.to_text(empty_bytes)), [])
+        # Now let's test our specific implementation to split commands
+        self.assertEqual(process.cmd_split(plain_str), [])
+        self.assertEqual(process.cmd_split(unicode_str), [])
+        self.assertEqual(process.cmd_split(empty_bytes), [])
+        unicode_command = u"avok\xe1do_test_runner arguments"
+        self.assertEqual(process.cmd_split(unicode_command),
+                         [u"avok\xe1do_test_runner",
+                          u"arguments"])
+
 
 class CmdResultTests(unittest.TestCase):