@Test
  public void testIsLeaseRecoverable() {
    assertTrue(RecoverLeaseFSUtils.isLeaseRecoverable(new DistributedFileSystem()));
    assertFalse(RecoverLeaseFSUtils.isLeaseRecoverable(new LocalFileSystem()));
  }
Test that isFileClosed makes us recover lease faster.
hbase-asyncfs/src/test/java/org/apache/hadoop/hbase/util/TestRecoverLeaseFSUtils.java