@Test
  public void testFileBucketCacheConfig() throws IOException {
    HBaseTestingUtil htu = new HBaseTestingUtil(this.conf);
    try {
      Path p = new Path(htu.getDataTestDir(), "bc.txt");
      FileSystem fs = FileSystem.get(this.conf);
      fs.create(p).close();
      this.conf.set(HConstants.BUCKET_CACHE_IOENGINE_KEY, "file:" + p);
      doBucketCacheConfigTest();
    } finally {
      htu.cleanupTestDir();
    }
  }
Assert that the caches are deployed with CombinedBlockCache and of the appropriate sizes.
hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestCacheConfig.java