### Question:
UserProducer { public void sendUserbyid(String id, String topic) { producer.send(topic, id); }  void sendUserbyid(String id, String topic);  }### Answer:
@Test void testSendUserbyid() { Users user = getRandomUser(); producer.sendUserbyid(""+user.getId(), this.topic); verify(kafkaProducer, times(1)).send("user", ""+user.getId()); }