/*
    * 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.genetics;
  
  
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.commons.math4.legacy.exception.OutOfRangeException;
  import org.junit.Assert;
  import org.junit.Test;
  
  public class ElitisticListPopulationTest {
  
      private static int counter = 0;
  
      @Test
      public void testNextGeneration() {
          ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203);
  
          for (int i=0; i<pop.getPopulationLimit(); i++) {
              pop.addChromosome(new DummyChromosome());
          }
  
          Population nextGeneration = pop.nextGeneration();
  
          Assert.assertEquals(20, nextGeneration.getPopulationSize());
      }
  
      @Test
      public void testSetElitismRate() {
          final double rate = 0.25;
          final ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203);
          pop.setElitismRate(rate);
          Assert.assertEquals(rate, pop.getElitismRate(), 1e-6);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testSetElitismRateTooLow() {
          final double rate = -0.25;
          final ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203);
          pop.setElitismRate(rate);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testSetElitismRateTooHigh() {
          final double rate = 1.25;
          final ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203);
          pop.setElitismRate(rate);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testConstructorTooLow() {
          final double rate = -0.25;
          new ElitisticListPopulation(100, rate);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testConstructorTooHigh() {
          final double rate = 1.25;
          new ElitisticListPopulation(100, rate);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testChromosomeListConstructorTooLow() {
          final List<Chromosome> chromosomes = Collections.emptyList();
          final double rate = -0.25;
          new ElitisticListPopulation(chromosomes, 100, rate);
      }
  
      @Test(expected = OutOfRangeException.class)
      public void testChromosomeListConstructorTooHigh() {
          final List<Chromosome> chromosomes = Collections.emptyList();
          final double rate = 1.25;
          new ElitisticListPopulation(chromosomes, 100, rate);
      }
  
      private static final class DummyChromosome extends Chromosome {
          private final int fitness;
  
          DummyChromosome() {
              this.fitness = counter;
              counter++;
          }
  
         @Override
         public double fitness() {
             return this.fitness;
         }
     }
 }