Create a new depot_tools_testing_lib to move utility modules there

tests/filesystem_mock.py

-# Copyright (c) 2011 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.
-
-import errno
-import os
-import re
-import StringIO
-
-
-def _RaiseNotFound(path):
-  raise IOError(errno.ENOENT, path, os.strerror(errno.ENOENT))
-
-
-class MockFileSystem(object):
-  """Stripped-down version of WebKit's webkitpy.common.system.filesystem_mock
-
-  Implements a filesystem-like interface on top of a dict of filenames ->
-  file contents. A file content value of None indicates that the file should
-  not exist (IOError will be raised if it is opened;
-  reading from a missing key raises a KeyError, not an IOError."""
-
-  def __init__(self, files=None):
-    self.files = files or {}
-    self.written_files = {}
-    self._sep = '/'
-
-  @property
-  def sep(self):
-    return self._sep
-
-  def _split(self, path):
-    return path.rsplit(self.sep, 1)
-
-  def abspath(self, path):
-    if path.endswith(self.sep):
-      return path[:-1]
-    return path
-
-  def dirname(self, path):
-    if self.sep not in path:
-      return ''
-    return self._split(path)[0] or self.sep
-
-  def exists(self, path):
-    return self.isfile(path) or self.isdir(path)
-
-  def isfile(self, path):
-    return path in self.files and self.files[path] is not None
-
-  def isdir(self, path):
-    if path in self.files:
-      return False
-    if not path.endswith(self.sep):
-      path += self.sep
-
-    # We need to use a copy of the keys here in order to avoid switching
-    # to a different thread and potentially modifying the dict in
-    # mid-iteration.
-    files = self.files.keys()[:]
-    return any(f.startswith(path) for f in files)
-
-  def join(self, *comps):
-    # TODO: Might want tests for this and/or a better comment about how
-    # it works.
-    return re.sub(re.escape(os.path.sep), self.sep, os.path.join(*comps))
-
-  def open_for_reading(self, path):
-    return StringIO.StringIO(self.read_binary_file(path))
-
-  def read_binary_file(self, path):
-    # Intentionally raises KeyError if we don't recognize the path.
-    if self.files[path] is None:
-      _RaiseNotFound(path)
-    return self.files[path]