private Properties getTopicProperties(final String changelog) {
        try (final Admin adminClient = createAdminClient()) {
            final ConfigResource configResource = new ConfigResource(ConfigResource.Type.TOPIC, changelog);
            try {
                final Config config = adminClient.describeConfigs(Collections.singletonList(configResource)).values().get(configResource).get();
                final Properties properties = new Properties();
                for (final ConfigEntry configEntry : config.entries()) {
                    if (configEntry.source() == ConfigEntry.ConfigSource.DYNAMIC_TOPIC_CONFIG) {
                        properties.put(configEntry.name(), configEntry.value());
                    }
                }
                return properties;
            } catch (final InterruptedException | ExecutionException e) {
                throw new RuntimeException(e);
            }
        }
    }
Tests related to internal topics in streams
streams/src/test/java/org/apache/kafka/streams/integration/InternalTopicIntegrationTest.java