Spring KafkaEmbedded Testing listener is not consuming message - spring-test

Question

i like to unit test some spring kafka listeners. This works fine in production, but i have some problems with the unit tests. I defined the configuration complettly with spring configuration beans but the listener is never called. Did i miss something?
#RunWith(SpringJUnit4ClassRunner.class)
#SpringBootTest(classes = {KafkaSpringBootTest.class})
#Configuration
#DirtiesContext
public class KafkaSpringBootTest {
#ClassRule
public static KafkaEmbedded embeddedKafka = new KafkaEmbedded(1);
#BeforeClass
public static void setup() {
System.setProperty("spring.kafka.bootstrap-servers", embeddedKafka.getBrokersAsString());
System.setProperty("spring.cloud.stream.kafka.binder.zkNodes", embeddedKafka.getZookeeperConnectionString());
System.setProperty("spring.kafka.consumer.auto-offset-reset", "earliest");
}
#Bean
public Map<String, Object> producerConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, embeddedKafka.getBrokersAsString());
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
#Bean
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
#Bean
public DefaultKafkaConsumerFactory<String, String> consumerFactory() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, embeddedKafka.getBrokersAsString());
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
return new DefaultKafkaConsumerFactory<>(props);
}
#Bean
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<>(producerFactory());
}
#Bean
public KafkaTransferListener kafkaTransferListener() {
return new KafkaTransferListener();
}
#Autowired
private KafkaTemplate<String, String> kafkaTemplate;
#Test
public void testSendMessage() throws InterruptedException {
System.out.println("now sending");
kafkaTemplate.send("test", "hello");
Thread.sleep(5000);
}
}
class KafkaTransferListener {
#KafkaListener(topics = "test")
public void listen(String test) {
System.out.println("received message via kafka: " + test);
}
}
Versions:
org.springframework.kafka:spring-kafka-test:2.0.0.RELEASE
org.apache.kafka:kafka_2.11:0.11.0.0
Thanks in advance

Answer 1

I don't see #SpringBootApplication configuration to be sure that Spring Kafka is auto-configured.
You use KafkaEmbedded and its properties to configure ProducerConfig, but at the same time I don't see how you configure ConsumerConfig. Essentially you should use the same properties from the EmbeddedKafka.
With the Boot auto-configuration you really don't need all that kung-fu. There is a simplest way to configure everything against EmbeddedKafka:
#BeforeClass
public static void setup() {
System.setProperty("spring.kafka.bootstrap-servers", embeddedKafka.getBrokersAsString());
System.setProperty("spring.cloud.stream.kafka.binder.zkNodes", embeddedKafka.getZookeeperConnectionString());
}
And you definitely must have #SpringBootApplication class in the same package as this test. Everything rest will be done by Boot.
See this sample on the matter.