001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.math.genetics; 018 019 import static org.junit.Assert.*; 020 import org.junit.Test; 021 022 public class TournamentSelectionTest { 023 024 private static int counter = 0; 025 026 @Test 027 public void testSelect() { 028 TournamentSelection ts = new TournamentSelection(2); 029 ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203); 030 031 for (int i=0; i<pop.getPopulationLimit(); i++) { 032 pop.addChromosome(new DummyChromosome()); 033 } 034 // how to write a test for stochastic method? 035 for (int i=0; i<20; i++) { 036 ChromosomePair pair = ts.select(pop); 037 // the worst chromosome should NEVER be selected 038 assertTrue(pair.getFirst().getFitness() > 0); 039 assertTrue(pair.getSecond().getFitness() > 0); 040 } 041 } 042 043 private static class DummyChromosome extends Chromosome { 044 private final int fitness; 045 046 public DummyChromosome() { 047 this.fitness = counter; 048 counter++; 049 } 050 051 public double fitness() { 052 return this.fitness; 053 } 054 } 055 056 }