@Test
public void testGetTimestampOfWriteIndexingPrewriteTs() throws IOException {

  // write column is null
  Assert.assertNull(lockCleaner.getTimestampOfWriteIndexingPrewriteTs(COLUMN, prewriteTs));
  // value of write column not equal to prewriteTs
  writePutColumn(COLUMN, prewriteTs - 1, commitTs - 1);
  writePutColumn(COLUMN, prewriteTs + 1, commitTs + 1);
  writeDeleteColumn(COLUMN, prewriteTs + 2, commitTs + 2);
  Assert.assertNull(lockCleaner.getTimestampOfWriteIndexingPrewriteTs(COLUMN, prewriteTs));
  // value of write column equals to prewriteTs
  writePutColumn(COLUMN, prewriteTs, commitTs);
  Long ts = lockCleaner.getTimestampOfWriteIndexingPrewriteTs(COLUMN, prewriteTs);
  Assert.assertEquals(commitTs, ts.longValue());
  ts = lockCleaner.getTimestampOfWriteIndexingPrewriteTs(COLUMN, prewriteTs + 2);
  Assert.assertEquals(commitTs + 2, ts.longValue());
}