How to use the dfvfs.lib.errors.PathSpecError function in dfvfs

def testOpenCloseLocation(self):
    """Test the open and close functionality using a location."""
    path_spec = path_spec_factory.Factory.NewPathSpec(
        definitions.TYPE_INDICATOR_APFS, location='/passwords.txt',
        parent=self._apfs_container_path_spec)
    file_object = apfs_file_io.APFSFile(self._resolver_context)

    file_object.open(path_spec=path_spec)
    self.assertEqual(file_object.get_size(), 116)
    file_object.close()

    # Try open with a path specification that has no parent.
    path_spec.parent = None

    with self.assertRaises(errors.PathSpecError):
      self._TestOpenCloseLocation(path_spec)

Raises:
      AccessError: if the access to open the file was denied.
      IOError: if the file-like object could not be opened.
      OSError: if the file-like object could not be opened.
      PathSpecError: if the path specification is incorrect.
      ValueError: if the path specification is invalid.
    """
    if not path_spec:
      raise ValueError('Missing path specification.')

    if path_spec.HasParent():
      raise errors.PathSpecError('Unsupported path specification with parent.')

    location = getattr(path_spec, 'location', None)
    if location is None:
      raise errors.PathSpecError('Path specification missing location.')

    self._current_offset = 0
    self._size = len(self._file_data)

def _OpenFileObject(self, path_spec):
    """Opens the file-like object defined by path specification.

    Args:
      path_spec (path.PathSpec): the path specification.

    Returns:
      pyregf.file: a Windows Registry file.

    Raises:
      PathSpecError: if the path specification is incorrect.
    """
    if not path_spec.HasParent():
      raise errors.PathSpecError(
          'Unsupported path specification without parent.')

    file_object = resolver.Resolver.OpenFileObject(
        path_spec.parent, resolver_context=self._resolver_context)
    regf_file = pyregf.file()
    regf_file.open_file_object(file_object)
    return regf_file

def _OpenFileObject(self, path_spec):
    """Opens the file-like object defined by path specification.

    Args:
      path_spec (PathSpec): path specification.

    Returns:
      pyqcow.file: a file-like object.

    Raises:
      PathSpecError: if the path specification is incorrect.
    """
    if not path_spec.HasParent():
      raise errors.PathSpecError(
          'Unsupported path specification without parent.')

    file_object = resolver.Resolver.OpenFileObject(
        path_spec.parent, resolver_context=self._resolver_context)
    qcow_file = pyqcow.file()
    qcow_file.open_file_object(file_object)
    return qcow_file

def _Open(self, path_spec, mode='rb'):
    """Opens the file system object defined by path specification.

    Args:
      path_spec (PathSpec): path specification.
      mode (Optional[str]): file access mode. The default is 'rb' which
          represents read-only binary.

    Raises:
      AccessError: if the access to open the file was denied.
      IOError: if the file system object could not be opened.
      PathSpecError: if the path specification is incorrect.
      ValueError: if the path specification is invalid.
    """
    if not path_spec.HasParent():
      raise errors.PathSpecError(
          'Unsupported path specification without parent.')

    file_object = resolver.Resolver.OpenFileObject(
        path_spec.parent, resolver_context=self._resolver_context)

    try:
      vshadow_volume = pyvshadow.volume()
      vshadow_volume.open_file_object(file_object)
    except:
      file_object.close()
      raise

    self._file_object = file_object
    self._vshadow_volume = vshadow_volume

Args:
      file_system (FileSystem): file system.
      mount_point (PathSpec): mount point path specification that refers
          to the base location of the file system.

    Raises:
      PathSpecError: if the mount point path specification is incorrect.
      ValueError: when file system or mount point is not set.
    """
    if not file_system or not mount_point:
      raise ValueError('Missing file system or mount point value.')

    if path_spec_factory.Factory.IsSystemLevelTypeIndicator(
        file_system.type_indicator):
      if not hasattr(mount_point, 'location'):
        raise errors.PathSpecError(
            'Mount point path specification missing location.')

    super(FileSystemSearcher, self).__init__()
    self._file_system = file_system
    self._mount_point = mount_point

Args:
      path_spec (PathSpec): a path specification.

    Returns:
      tarfile.TARInfo: TAR info or None if it does not exist.

    Raises:
      PathSpecError: if the path specification is incorrect.
    """
    location = getattr(path_spec, 'location', None)
    if location is None:
      raise errors.PathSpecError('Path specification missing location.')

    if not location.startswith(self.LOCATION_ROOT):
      raise errors.PathSpecError('Invalid location in path specification.')

    if len(location) == 1:
      return None

    try:
      return self._tar_file.getmember(location[1:])
    except KeyError:
      pass

def _OpenFileObject(self, path_spec):
    """Opens the file-like object defined by path specification.

    Args:
      path_spec (PathSpec): path specification.

    Returns:
      FileIO: a file-like object.

    Raises:
      PathSpecError: if the path specification is incorrect.
    """
    if not path_spec.HasParent():
      raise errors.PathSpecError(
          'Unsupported path specification without parent.')

    resolver.Resolver.key_chain.ExtractCredentialsFromPathSpec(path_spec)

    file_object = resolver.Resolver.OpenFileObject(
        path_spec.parent, resolver_context=self._resolver_context)
    fvde_volume = pyfvde.volume()
    fvde.FVDEVolumeOpen(
        fvde_volume, path_spec, file_object, resolver.Resolver.key_chain)
    return fvde_volume

def _Open(self, path_spec, mode='rb'):
    """Opens the file system defined by path specification.

    Args:
      path_spec (PathSpec): path specification.
      mode (Optional[str]): file access mode. The default is 'rb'
          read-only binary.

    Raises:
      AccessError: if the access to open the file was denied.
      IOError: if the file system could not be opened.
      PathSpecError: if the path specification is incorrect.
      ValueError: if the path specification is invalid.
    """
    if not path_spec.HasParent():
      raise errors.PathSpecError(
          'Unsupported path specification without parent.')

    resolver.Resolver.key_chain.ExtractCredentialsFromPathSpec(path_spec)

    fvde_volume = pyfvde.volume()
    file_object = resolver.Resolver.OpenFileObject(
        path_spec.parent, resolver_context=self._resolver_context)

    try:
      fvde.FVDEVolumeOpen(
          fvde_volume, path_spec, file_object, resolver.Resolver.key_chain)
    except:
      file_object.close()
      raise

    self._fvde_volume = fvde_volume

path_spec (PathSpec): path specification.
      mode (Optional[str]): file access mode.

    Raises:
      AccessError: if the access to open the file was denied.
      IOError: if the file-like object could not be opened.
      OSError: if the file-like object could not be opened.
      PathSpecError: if the path specification is incorrect.
      ValueError: if the path specification is invalid.
    """
    if not self._file_object_set_in_init and not path_spec:
      raise ValueError('Missing path specification.')

    if not self._file_object_set_in_init:
      if not path_spec.HasParent():
        raise errors.PathSpecError(
            'Unsupported path specification without parent.')

      self._encoding_method = getattr(path_spec, 'encoding_method', None)

      if self._encoding_method is None:
        raise errors.PathSpecError(
            'Path specification missing encoding method.')

      self._file_object = resolver.Resolver.OpenFileObject(
          path_spec.parent, resolver_context=self._resolver_context)