private void prepareExpectedKVs(long latestDelTS) {
    final List<Cell> filteredKVs = new ArrayList<>();
    for (Cell kv : expectedKVs) {
      if (kv.getTimestamp() > latestDelTS || latestDelTS == -1) {
        filteredKVs.add(kv);
      }
    }
    expectedKVs = filteredKVs;
    Collections.sort(expectedKVs, CellComparatorImpl.COMPARATOR);
  }
Disable this when this test fails hopelessly and you need to debug a simpler case.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSeekOptimizations.java