KafkaMessageListenerContainer.getAssignedPartitions returning 0 - spring

Question

I am trying to run a test case with Kafka API with below test case code -
Taken from https://www.codenotfound.com/spring-kafka-consumer-producer-example.html
//SpringKafkaApplicationTest .java
import static org.assertj.core.api.Assertions.assertThat;
import java.util.concurrent.TimeUnit;
import org.junit.Before;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.kafka.config.KafkaListenerContainerFactory;
import org.springframework.kafka.config.KafkaListenerEndpoint;
import org.springframework.kafka.config.KafkaListenerEndpointRegistry;
import org.springframework.kafka.listener.MessageListenerContainer;
import org.springframework.kafka.test.rule.KafkaEmbedded;
import org.springframework.kafka.test.utils.ContainerTestUtils;
import org.springframework.test.context.junit4.SpringRunner;
//#TestExecutionListeners( { DependencyInjectionTestExecutionListener.class })
#RunWith(SpringRunner.class)
#SpringBootTest(classes= {SpringKafkaIntegrationApplication.class },webEnvironment = WebEnvironment.RANDOM_PORT)
public class SpringKafkaApplicationTest {
private static String BOOT_TOPIC = "boot.t";
#Autowired
private Sender sender;
#Autowired
private Receiver receiver;
#Autowired
private KafkaListenerEndpointRegistry kafkaListenerEndpointRegistry;
#ClassRule
public static KafkaEmbedded embeddedKafka = new KafkaEmbedded(1, true, BOOT_TOPIC);
#Before
public void setUp() throws Exception {
// wait until the partitions are assigned
// kafkaListenerEndpointRegistry.registerListenerContainer(endpoint, factory);
for (MessageListenerContainer messageListenerContainer : kafkaListenerEndpointRegistry
.getListenerContainers()) {
**Below line gives issue**
ContainerTestUtils.waitForAssignment(messageListenerContainer,
embeddedKafka.getPartitionsPerTopic());
}
}
#Test
public void testReceive() throws Exception {
sender.send(BOOT_TOPIC, "Hello");
System.out.println("check");
receiver.getLatch().await(10000, TimeUnit.MILLISECONDS);
// receiver.receive(BOOT_TOPIC);
assertThat(receiver.getLatch().getCount()).isEqualTo(0);
}
}
I have defined the topics inside the application.yml as below-
spring:
kafka:
consumer:
auto-offset-reset: earliest
group-id: boot
kafka:
topic:
boot: boot.t
Inside ContainerTestUtils class inside waitForAssignment method with below call returns assignedPartitions = null
int count = 0;
....
Collection<?> assignedPartitions = (Collection<?>) getAssignedPartitions.invoke(aContainer);
if (assignedPartitions != null) {
count += assignedPartitions.size();
}
...
So the count above remains 0. But I get the assertion failure as below:
org.junit.ComparisonFailure: expected:<[2]> but was:<[0]>