content: /*
   * 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.bifromq.basescheduler;
  
  import static org.awaitility.Awaitility.await;
  import static org.testng.Assert.assertEquals;
  import static org.testng.Assert.assertTrue;
  
  import java.time.Duration;
  import lombok.extern.slf4j.Slf4j;
  import org.testng.annotations.Test;
  
  @Slf4j
  public class MovingAverageTest {
      @Test
      public void baseCase() {
          MovingAverage movingAverage = new MovingAverage(1, Duration.ofMillis(100));
          assertEquals(movingAverage.estimate(), 0);
          movingAverage.observe(10);
          assertEquals(movingAverage.estimate(), 10);
          assertEquals(movingAverage.max(), 10);
          movingAverage.observe(20);
          assertEquals(movingAverage.estimate(), 20);
          assertEquals(movingAverage.max(), 20);
          await().until(() -> movingAverage.estimate() == 0L);
      }
  
      @Test
      public void dropOldestObservation() {
          MovingAverage movingAverage = new MovingAverage(2, Duration.ofSeconds(60));
          movingAverage.observe(10);
          movingAverage.observe(20);
          assertEquals(movingAverage.estimate(), 15);
          assertEquals(movingAverage.max(), 20);
  
          movingAverage.observe(20);
          assertEquals(movingAverage.estimate(), 20);
          assertEquals(movingAverage.max(), 20);
  
          movingAverage.observe(30);
          assertEquals(movingAverage.estimate(), 25);
          assertEquals(movingAverage.max(), 30);
      }
  
      @Test
      public void dropStaledObservation() throws InterruptedException {
          MovingAverage movingAverage = new MovingAverage(3, Duration.ofMillis(10));
          movingAverage.observe(30);
          movingAverage.observe(30);
          movingAverage.observe(30);
          assertEquals(movingAverage.estimate(), 30);
  
          Thread.sleep(20);
          movingAverage.observe(40);
          movingAverage.observe(10);
          assertEquals(movingAverage.estimate(), 25);
      }
  
      @Test
      public void dataExpiration() throws InterruptedException {
          MovingAverage movingAverage = new MovingAverage(5, Duration.ofMillis(500));
          movingAverage.observe(100);
          movingAverage.observe(200);
          // Wait longer than freshness period
          Thread.sleep(600);
          movingAverage.observe(300);
          assertTrue(Math.abs(300 - movingAverage.estimate()) < 1);
          assertEquals(300, movingAverage.max());
      }
  }
  