@SuppressWarnings("WeakerAccess")
    public TimestampExtractor defaultTimestampExtractor() {
        return getConfiguredInstance(DEFAULT_TIMESTAMP_EXTRACTOR_CLASS_CONFIG, TimestampExtractor.class);
    }
@Test
    public void shouldUseCorrectDefaultsWhenNoneSpecified() {
        final StreamsConfig config = new StreamsConfig(getStreamsConfig());

        assertInstanceOf(FailOnInvalidTimestamp.class, config.defaultTimestampExtractor());
        assertThrows(ConfigException.class, config::defaultKeySerde);
        assertThrows(ConfigException.class, config::defaultValueSerde);
    }