@Test
public void typical() throws Exception {

  String logDir = temp.getRoot().getAbsolutePath();
  TopicPartition topicPartition = new TopicPartition("topic", 0);
  Map<TopicPartition, Replica> replicaByPartition = Collections.singletonMap(topicPartition, new Replica(logDir, 0L));
  Map<String, Disk> result = underTest.apply(replicaByPartition);
  assertThat(result.size(), is(1));
  Disk disk = result.get(logDir);
  assertThat(disk.getFree() > 0L, is(true));
  assertThat(disk.getTotal() > 0L, is(true));
}