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.time;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  
  import alluxio.util.CommonUtils;
  
  import org.junit.Test;
  
  /**
   * Tests for the {@link ExponentialTimer}.
   */
  public class ExponentialTimerTest {
  
    /**
     * Tests that the maximum total wait time is respected.
     */
    @Test
    public void expiration() {
      int maxTotalWaitTimeMs = 1000;
      ExponentialTimer timer = new ExponentialTimer(0, 0, 0, maxTotalWaitTimeMs);
      assertEquals(ExponentialTimer.Result.READY, timer.tick());
      CommonUtils.sleepMs(maxTotalWaitTimeMs);
      assertEquals(ExponentialTimer.Result.EXPIRED, timer.tick());
    }
  
    /**
     * Tests the exponential back-off logic.
     */
    @Test(timeout = 2000)
    public void backoff() {
      int n = 10;
      ExponentialTimer timer = new ExponentialTimer(1, 1000, 0, 1000);
      long start = System.currentTimeMillis();
      for (int i = 0; i < n; i++) {
        while (timer.tick() == ExponentialTimer.Result.NOT_READY) {
          CommonUtils.sleepMs(10);
        }
        long now = System.currentTimeMillis();
        assertTrue(now - start >= (1 << i - 1));
      }
    }
  }
  