kafka producer nuit test

To perform a Kafka producer unit test, you can use a testing framework like JUnit or TestNG and follow these steps:

1. Set up a mock Kafka broker or use an embedded Kafka server for testing.
2. Create a Kafka producer configuration with the necessary properties like bootstrap servers, serializer class, etc.
3. Create a Kafka producer instance using the configuration.
4. Create a mock record or use a real record that you want to produce to Kafka.
5. Use the producer instance to send the record to a Kafka topic.
6. Verify that the record was successfully sent to the topic by consuming it from the same topic using a Kafka consumer instance.

Here's an example test method using JUnit:

@Test
public void testKafkaProducer() throws Exception {
    // Set up a mock Kafka broker or use an embedded Kafka server for testing.

    // Create a Kafka producer configuration with the necessary properties.
    Properties props = new Properties();
    props.put("bootstrap.servers", "localhost:9092");
    props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
    props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

    // Create a Kafka producer instance using the configuration.
    KafkaProducer<String, String> producer = new KafkaProducer<>(props);

    // Create a mock record or use a real record that you want to produce to Kafka.
    ProducerRecord<String, String> record = new ProducerRecord<>("test-topic", "key", "value");

    // Use the producer instance to send the record to a Kafka topic.
    producer.send(record);

    // Verify that the record was successfully sent to the topic by consuming it from the same topic using a Kafka consumer instance.
    KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
    consumer.subscribe(Collections.singletonList("test-topic"));
    ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(10));
    assertEquals(1, records.count());
    assertEquals("key", records.iterator().next().key());
    assertEquals("value", records.iterator().next().value());

    // Clean up resources like the producer and consumer instances.
    producer.close();
    consumer.close();
}