Issue 6600: RunCommand should return an object with various attributes

Change-Id: I6b9333fcf1325dbe141ad387f52d85781de96819

BUG=chromium-os:6600
TEST=added 8 test cases for RunCommand (up from zero :-) Ran all tests and
verified all passed. No regression either

Review URL: http://codereview.chromium.org/3307022

chromite/lib/cros_build_lib.py

@@ -10,6 +10,22 @@ import sys
 
 _STDOUT_IS_TTY = hasattr(sys.stdout, 'isatty') and sys.stdout.isatty()
 
+
+class CommandResult(object):
+  """An object to store various attributes of a child process."""
+
+  def __init__(self):
+    self.cmd = None
+    self.error = None
+    self.output = None
+    self.returncode = None
+
+
+class RunCommandError(Exception):
+  """Error caught in RunCommand() method."""
+  pass
+
+
 def RunCommand(cmd, print_cmd=True, error_ok=False, error_message=None,
                exit_code=False, redirect_stdout=False, redirect_stderr=False,
                cwd=None, input=None, enter_chroot=False, shell=False):
@@ -36,6 +52,7 @@ def RunCommand(cmd, print_cmd=True, error_ok=False, error_message=None,
   stderr = None
   stdin = None
   output = ''
+  cmd_result = CommandResult()
 
   # Modify defaults based on parameters.
   if redirect_stdout:  stdout = subprocess.PIPE
@@ -51,25 +68,27 @@ def RunCommand(cmd, print_cmd=True, error_ok=False, error_message=None,
   # Print out the command before running.
   if print_cmd:
     Info('RunCommand: %s' % cmd_str)
+  cmd_result.cmd = cmd_str
 
   try:
-    proc = subprocess.Popen(cmd, cwd=cwd, stdin=stdin,
+    proc = subprocess.Popen(cmd_str, cwd=cwd, stdin=stdin,
                             stdout=stdout, stderr=stderr,
                             shell=shell)
-    (output, error) = proc.communicate(input)
+    (cmd_result.output, cmd_result.error) = proc.communicate(input)
     if exit_code:
-      return proc.returncode
+      cmd_result.returncode = proc.returncode
 
     if not error_ok and proc.returncode:
-      raise Exception('Command "%s" failed.\n' % cmd_str +
-                      (error_message or error or output or ''))
+      msg = ('Command "%s" failed.\n' % cmd_str +
+             (error_message or cmd_result.error or cmd_result.output or ''))
+      raise RunCommandError(msg)
   except Exception,e:
     if not error_ok:
       raise
     else:
       Warning(str(e))
 
-  return output
+  return cmd_result
 
 
 class Color(object):

chromite/lib/cros_build_lib_unittest.py

@@ -1,12 +1,120 @@
 #!/usr/bin/python
+#
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 
 import errno
 import os
-import unittest 
 import shutil
+import subprocess
 import tempfile
-
+import unittest
 import cros_build_lib
+import mox
+
+
+class TestRunCommand(unittest.TestCase):
+
+  def setUp(self):
+    self.mox = mox.Mox()
+    self.mox.StubOutWithMock(subprocess, 'Popen', use_mock_anything=True)
+    self.proc_mock = self.mox.CreateMockAnything()
+    self.cmd = 'test cmd'
+    self.error = 'test error'
+    self.output = 'test output'
+
+  def tearDown(self):
+    self.mox.UnsetStubs()
+    self.mox.VerifyAll()
+
+  def _assertCrEqual(self, expected, actual):
+    """Helper method to compare two CommandResult objects.
+
+    This is needed since assertEqual does not know how to compare two
+    CommandResult objects.
+
+    Args:
+      expected: a CommandResult object, expected result.
+      actual: a CommandResult object, actual result.
+    """
+    self.assertEqual(expected.cmd, actual.cmd)
+    self.assertEqual(expected.error, actual.error)
+    self.assertEqual(expected.output, actual.output)
+    self.assertEqual(expected.returncode, actual.returncode)
+
+  def _testCmd(self, cmd, sp_kv=dict(), rc_kv=dict()):
+    """Factor out common setup logic for testing --cmd.
+
+    Args:
+      cmd: a string or an array of strings.
+      sp_kv: key-value pairs passed to subprocess.Popen().
+      rc_kv: key-value pairs passed to RunCommand().
+    """
+    expected_result = cros_build_lib.CommandResult()
+    expected_result.cmd = self.cmd
+    expected_result.error = self.error
+    expected_result.output = self.output
+    if 'exit_code' in rc_kv:
+      expected_result.returncode = self.proc_mock.returncode
+
+    arg_dict = dict()
+    for attr in 'cwd stdin stdout stderr shell'.split():
+      if attr in sp_kv:
+        arg_dict[attr] = sp_kv[attr]
+      else:
+        if attr == 'shell':
+          arg_dict[attr] = False
+        else:
+          arg_dict[attr] = None
+
+    subprocess.Popen(self.cmd, **arg_dict).AndReturn(self.proc_mock)
+    self.proc_mock.communicate(None).AndReturn((self.output, self.error))
+    self.mox.ReplayAll()
+    actual_result = cros_build_lib.RunCommand(cmd, **rc_kv)
+    self._assertCrEqual(expected_result, actual_result)
+
+  def testReturnCodeZeroWithArrayCmd(self):
+    """--enter_chroot=False and --cmd is an array of strings."""
+    self.proc_mock.returncode = 0
+    cmd_list = ['foo', 'bar', 'roger']
+    self.cmd = 'foo bar roger'
+    self._testCmd(cmd_list, rc_kv=dict(exit_code=True))
+
+  def testReturnCodeZeroWithArrayCmdEnterChroot(self):
+    """--enter_chroot=True and --cmd is an array of strings."""
+    self.proc_mock.returncode = 0
+    cmd_list = ['foo', 'bar', 'roger']
+    self.cmd = './enter_chroot.sh -- %s' % ' '.join(cmd_list)
+    self._testCmd(cmd_list, rc_kv=dict(enter_chroot=True))
+
+  def testReturnCodeNotZeroErrorOkNotRaisesError(self):
+    """Raise error when proc.communicate() returns non-zero."""
+    self.proc_mock.returncode = 1
+    self._testCmd(self.cmd, rc_kv=dict(error_ok=True))
+
+  def testSubprocessCommunicateExceptionRaisesError(self):
+    """Verify error raised by communicate() is caught."""
+    subprocess.Popen(self.cmd, cwd=None, stdin=None, stdout=None, stderr=None,
+                     shell=False).AndReturn(self.proc_mock)
+    self.proc_mock.communicate(None).AndRaise(ValueError)
+    self.mox.ReplayAll()
+    self.assertRaises(ValueError, cros_build_lib.RunCommand, self.cmd)
+
+  def testSubprocessCommunicateExceptionNotRaisesError(self):
+    """Don't re-raise error from communicate() when --error_ok=True."""
+    expected_result = cros_build_lib.CommandResult()
+    cmd_str = './enter_chroot.sh -- %s' % self.cmd
+    expected_result.cmd = cmd_str
+
+    subprocess.Popen(cmd_str, cwd=None, stdin=None, stdout=None, stderr=None,
+                     shell=False).AndReturn(self.proc_mock)
+    self.proc_mock.communicate(None).AndRaise(ValueError)
+    self.mox.ReplayAll()
+    actual_result = cros_build_lib.RunCommand(self.cmd, error_ok=True,
+                                              enter_chroot=True)
+    self._assertCrEqual(expected_result, actual_result)
+
 
 class TestListFiles(unittest.TestCase):
 
@@ -36,9 +144,7 @@ class TestListFiles(unittest.TestCase):
       tmp.close()
 
   def testTraverse(self):
-    """
-    Test that we are traversing the directory properly
-    """
+    """Test that we are traversing the directory properly."""
     dir_structure = ['one/two/test.txt', 'one/blah.py',
                      'three/extra.conf']
     self._createNestedDir(dir_structure)
@@ -50,9 +156,7 @@ class TestListFiles(unittest.TestCase):
         self.fail('%s was not found in %s' % (file, dir_structure))
 
   def testEmptyFilePath(self):
-    """
-    Test that we return nothing when directories are empty
-    """
+    """Test that we return nothing when directories are empty."""
     dir_structure = ['one/', 'two/', 'one/a/']
     self._createNestedDir(dir_structure)
     files = cros_build_lib.ListFiles(self.root_dir)