private int countStoreFiles() throws IOException {
    HStore store = region.getStore(COLUMN_FAMILY);
    return store.getStorefilesCount();
  }
This test will first generate store files, then bulk load them and trigger the compaction. When
compaction, the cell value will be larger than the threshold.
hbase-server/src/test/java/org/apache/hadoop/hbase/mob/TestMobStoreCompaction.java