@Parameters
  public static Collection<Object[]> parameters() {
    List<Object[]> params = new ArrayList<>();
    for (int numFreshFiles = 1; numFreshFiles <= 3; ++numFreshFiles) {
      params.add(new Object[] { numFreshFiles });
    }
    return params;
  }
Test the optimization that does not scan files where all timestamps are expired.
hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestScannerSelectionUsingTTL.java