content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.worker.block.annotator;
  
  import alluxio.conf.Configuration;
  import alluxio.conf.PropertyKey;
  import alluxio.worker.block.BlockStoreLocation;
  import alluxio.worker.block.meta.StorageDir;
  
  import org.junit.Before;
  import org.junit.Test;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Random;
  
  public class LRFUAnnotatorTest extends AbstractBlockAnnotatorTest {
    /**
     * Sets up base class for LRUAnnotator.
     */
    @Before
    public void before() throws Exception {
      Configuration.set(PropertyKey.WORKER_BLOCK_ANNOTATOR_CLASS,
          LRFUAnnotator.class.getName());
      // To make it behave close to an absolute LFU.
      Configuration.set(PropertyKey.WORKER_BLOCK_ANNOTATOR_LRFU_STEP_FACTOR, 0);
      init();
    }
  
    @Test
    public void testLRFU() throws Exception {
      Random rand = new Random();
      List<Long> expectedList = new ArrayList<>();
      for (long i = 0; i < 100; i++) {
        StorageDir pickedDir = getDir(rand.nextInt(2), rand.nextInt(2));
        createBlock(i, pickedDir);
        for (int j = 0; j < i * 2 + 1; j++) {
          accessBlock(i);
        }
        expectedList.add(i);
      }
  
      validateIterator(mBlockIterator.getIterator(BlockStoreLocation.anyTier(), BlockOrder.NATURAL),
          expectedList.iterator());
  
      Collections.reverse(expectedList);
      validateIterator(mBlockIterator.getIterator(BlockStoreLocation.anyTier(), BlockOrder.REVERSE),
          expectedList.iterator());
    }
  }
  