/*
    * 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.commons.math4.legacy.stat.descriptive.summary;
  
  import org.apache.commons.math4.legacy.stat.descriptive.StorelessUnivariateStatistic;
  import org.apache.commons.math4.legacy.stat.descriptive.StorelessUnivariateStatisticAbstractTest;
  import org.apache.commons.math4.legacy.stat.descriptive.UnivariateStatistic;
  import org.junit.Assert;
  import org.junit.Test;
  
  /**
   * Test cases for the {@link Sum} class.
   */
  public class SumTest extends StorelessUnivariateStatisticAbstractTest{
  
      protected Sum stat;
  
      /**
       * {@inheritDoc}
       */
      @Override
      public UnivariateStatistic getUnivariateStatistic() {
          return new Sum();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public double expectedValue() {
          return this.sum;
      }
  
      /**Expected value for  the testArray defined in UnivariateStatisticAbstractTest */
      public double expectedWeightedValue() {
          return this.weightedSum;
      }
  
      @Test
      public void testSpecialValues() {
          Sum sum = new Sum();
          Assert.assertEquals(0, sum.getResult(), 0);
          sum.increment(1);
          Assert.assertEquals(1, sum.getResult(), 0);
          sum.increment(Double.POSITIVE_INFINITY);
          Assert.assertEquals(Double.POSITIVE_INFINITY, sum.getResult(), 0);
          sum.increment(Double.NEGATIVE_INFINITY);
          Assert.assertTrue(Double.isNaN(sum.getResult()));
          sum.increment(1);
          Assert.assertTrue(Double.isNaN(sum.getResult()));
      }
  
      @Test
      public void testWeightedSum() {
          Sum sum = new Sum();
          Assert.assertEquals(expectedWeightedValue(),
                              sum.evaluate(testArray, testWeightsArray, 0, testArray.length), getTolerance());
          Assert.assertEquals(expectedValue(),
                              sum.evaluate(testArray, unitWeightsArray, 0, testArray.length), getTolerance());
      }
  
      @Override
      protected void checkClearValue(StorelessUnivariateStatistic statistic) {
          Assert.assertEquals(0, statistic.getResult(), 0);
      }
  }