def METHOD_NAME(self, mock_urlretrieve):
    file_src = self.get_mock_file_base("ftp://snapcraft.io/snapcraft.yaml", "dir")
    file_src.pull()
    self.assertThat(mock_urlretrieve.call_count, Equals(1))
    self.assertThat(mock_urlretrieve.call_args[0][0], Equals(file_src.source))
    self.assertThat(mock_urlretrieve.call_args[0][1], Equals(file_src.file))