/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.hadoop.chukwa.datacollection;
  
  import junit.framework.TestCase;
  
  /**
   * Verifies that the stats manager calculates stats properly. This test will take
   * at least 13 seconds to run.
   */
  public class TestOffsetStatsManager extends TestCase {
  
    org.apache.hadoop.chukwa.datacollection.OffsetStatsManager<DummyKey> statsManager = null;
    DummyKey dummyKey = new DummyKey();
  
    protected void setUp() throws Exception {
      statsManager = new OffsetStatsManager<DummyKey>();
      dummyKey = new DummyKey();
    }
  
    public void testCalcAverageRate() throws InterruptedException {
  
      // add roughly 1000 bytes per second for about 5 seconds
      for (int i = 0; i < 5; i++) {
        statsManager.addOffsetDataPoint(dummyKey, 1000 * i, System.currentTimeMillis());
        Thread.sleep(1000);
      }
  
      // calculate 5 second average
      double rate = statsManager.calcAverageRate(dummyKey, 5);
      assertTrue("Invalid average, expected about 1 byte/sec, found " + rate,
                   Math.abs(1000 - rate) < 1.5);
    }
  
    public void testCalcAverageRateStaleData() throws InterruptedException {
  
      // add offsets for about 5 seconds, but timestamp them 3 seconds ago to make
      // them stale
      for (int i = 0; i < 5; i++) {
        statsManager.addOffsetDataPoint(dummyKey, 1000 * i, System.currentTimeMillis() - 3000L);
        Thread.sleep(1000);
      }
  
      // calculate 5 second average
      double rate = statsManager.calcAverageRate(dummyKey, 5);
      assertEquals("Should have gotten a stale data response", -1.0, rate);
    }
  
    public void testCalcAverageRateNotEnoughData() throws InterruptedException {
  
      // add offsets for about 3 seconds
      for (int i = 0; i < 3; i++) {
        statsManager.addOffsetDataPoint(dummyKey, 1000 * i, System.currentTimeMillis());
        Thread.sleep(1000);
      }
  
      // calculate 5 second average
      double rate = statsManager.calcAverageRate(dummyKey, 5);
      assertEquals("Should have gotten a stale data response", -1.0, rate);
    }
  
    private static class DummyKey {}
  }