@Test
public void init() throws Exception {

  underTest.init(1L, rebalanceListener);
  ArgumentCaptor<KafkaRebalanceListener> captor = ArgumentCaptor.forClass(KafkaRebalanceListener.class);
  verify(consumer).subscribe(eq(singletonList(topicName)), captor.capture());
  assertThat(captor.getValue().getRebalanceListener(), is(rebalanceListener));
}