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.beam.runners.dataflow.worker.counters;
  
  import static org.junit.Assert.assertEquals;
  
  import java.util.List;
  import org.apache.beam.runners.dataflow.worker.counters.CounterFactory.CounterDistribution;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Unit tests for {@link CounterFactory} and nested classes. */
  @RunWith(JUnit4.class)
  public class CounterFactoryTest {
    /**
     * Validate boundary values in the full range of positive long integers that they are placed in
     * the correct CounterDistribution histogram bucket. The naive bucketing implementation of using
     * Math.log10 introduces error for large values due to precision loss in converting large integers
     * to and from floating point.
     */
    @Test
    public void testCounterDistributionCalculateBucket() {
      assertEquals(0, CounterDistribution.calculateBucket(0));
  
      int bucket = 1;
      long powerOfTen = 1;
      while (powerOfTen > 0 /* break on overflow */) {
        for (int multiplier : new int[] {1, 2, 5}) {
          long value = powerOfTen * multiplier;
          verifyDistributionBucket(value - 1, bucket - 1);
          verifyDistributionBucket(value, bucket);
          bucket++;
        }
        powerOfTen *= 10;
      }
    }
  
    private void verifyDistributionBucket(long value, int expectedBucket) {
      int actualBucket = CounterDistribution.calculateBucket(value);
      assertEquals(String.format("Bucket value for %d", value), expectedBucket, actualBucket);
    }
  
    @Test
    public void testCounterDistributionAddValue() {
      CounterDistribution counter = CounterDistribution.empty();
      List<Long> expectedBuckets = ImmutableList.of(1L, 3L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 1L);
      for (long value : new long[] {1, 500, 2, 3, 1000, 4}) {
        counter = counter.addValue(value);
      }
      assertEquals(expectedBuckets, counter.getBuckets());
      assertEquals(1250030.0, counter.getSumOfSquares(), 0);
      assertEquals(1510, counter.getSum());
      assertEquals(1, counter.getFirstBucketOffset());
      assertEquals(6, counter.getCount());
      assertEquals(1, counter.getMin());
      assertEquals(1000, counter.getMax());
    }
  }
  