PyAuto test for renderer crash reporting

chrome/test/pyautolib/pyauto_utils.py

+#!/usr/bin/python
+
+# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utilities for PyAuto."""
+
+import logging
+import os
+import shutil
+import tempfile
+
+
+class ExistingPathReplacer(object):
+  """Facilitates backing up a given path (file or dir)..
+
+  Often you want to manipulate a directory or file for testing but don't want to
+  meddle with the existing contents.  This class lets you make a backup, and
+  reinstate the backup when done.  A backup is made in an adjacent directory,
+  so you need to make sure you have write permissions to the parent directory.
+
+  Works seemlessly in cases where the requested path already exists, or not.
+
+  Automatically reinstates the backed up path (if any) when object is deleted.
+  """
+  _path = ''
+  _backup_dir = None  # dir to which existing content is backed up
+  _backup_basename = ''
+
+  def __init__(self, path, path_type='dir'):
+    """Initialize the object, making backups if necessary.
+
+    Args:
+      path: the requested path to file or directory
+      path_type: path type. Options: 'file', 'dir'. Default: 'dir'
+    """
+    assert path_type in ('file', 'dir'), 'Invalid path_type: %s' % path_type
+    self._path_type = path_type
+    self._path = path
+    if os.path.exists(self._path):
+      if 'dir' == self._path_type:
+        assert os.path.isdir(self._path), '%s is not a directory' % self._path
+      else:
+        assert os.path.isfile(self._path), '%s is not a file' % self._path
+      # take a backup
+      self._backup_basename = os.path.basename(self._path)
+      self._backup_dir = tempfile.mkdtemp(dir=os.path.dirname(self._path),
+                                          prefix='bkp-' + self._backup_basename)
+      logging.info('Backing up %s in %s' % (self._path, self._backup_dir))
+      shutil.move(self._path,
+                  os.path.join(self._backup_dir, self._backup_basename))
+    self._CreateRequestedPath()
+
+  def __del__(self):
+    """Cleanup. Reinstate backup."""
+    self._CleanupRequestedPath()
+    if self._backup_dir:  # Reinstate, if backed up.
+      from_path = os.path.join(self._backup_dir, self._backup_basename)
+      logging.info('Reinstating backup from %s to %s' % (from_path, self._path))
+      shutil.move(from_path, self._path)
+    self._RemoveBackupDir()
+
+  def _CreateRequestedPath(self):
+    if 'dir' == self._path_type:
+      os.mkdir(self._path)
+    else:
+      open(self._path, 'w').close()
+
+  def _CleanupRequestedPath(self):
+    if os.path.exists(self._path):
+      if os.path.isdir(self._path):
+        shutil.rmtree(self._path, ignore_errors=True)
+      else:
+        os.remove(self._path)
+
+  def _RemoveBackupDir(self):
+    if self._backup_dir and os.path.isdir(self._backup_dir):
+      shutil.rmtree(self._backup_dir, ignore_errors=True)