def METHOD_NAME(self):
    with NamedTemporaryFile() as tmp_file:
        tmp_file.write(b"un")
        tmp_file.flush()
        c = ConfigDict({"f": f'{{{{ file:{tmp_file.name} }}}}'})
        # first read operation
        m0 = Mock(return_value=0)
        c._resolver._get_time = m0
        self.assertEqual(c["f"], "un")
        m0.assert_called_once()
        tmp_file.seek(0)
        tmp_file.write(b"undeux")
        tmp_file.flush()
        # read from cache
        m599 = Mock(return_value=599)
        c._resolver._get_time = m599
        self.assertEqual(c["f"], "un")
        m599.assert_called_once()
        # force expiry (time > 0 + default ttl)
        m601 = Mock(return_value=601)
        c._resolver._get_time = m601
        self.assertEqual(c["f"], "undeux")
        m601.assert_has_calls([call(), call()])