@BeforeEach
    public void before() {
        streamsProp = new Properties();
        streamsProp.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
        streamsProp.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
        streamsProp.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
        streamsProp.put(StreamsConfig.STATE_DIR_CONFIG, TestUtils.tempDirectory().getPath());
        streamsProp.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 100L);
        streamsProp.put(StreamsConfig.STATESTORE_CACHE_MAX_BYTES_CONFIG, 0);
        streamsProp.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
    }
Tests related to internal topics in streams
streams/src/test/java/org/apache/kafka/streams/integration/InternalTopicIntegrationTest.java