'Fails unless the specified file is empty.
The default error message can be overridden with the ``msg`` argument.'

def file_should_be_empty(self, path, msg=None):

    path = self._absnorm(path)
    if (not os.path.isfile(path)):
        self._error(("File    '%s'    does    not    exist." % path))
    size = os.stat(path).st_size
    if (size > 0):
        self._fail(msg, ("File    '%s'    is    not    empty.    Size:    %d    bytes." % (path, size)))
    self._link("File    '%s'    is    empty.", path)
