1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math4.legacy.genetics;
18
19 import org.junit.Assert;
20 import org.junit.Test;
21
22 public class TournamentSelectionTest {
23
24 private static int counter = 0;
25
26 @Test
27 public void testSelect() {
28 TournamentSelection ts = new TournamentSelection(2);
29 ElitisticListPopulation pop = new ElitisticListPopulation(100, 0.203);
30
31 for (int i=0; i<pop.getPopulationLimit(); i++) {
32 pop.addChromosome(new DummyChromosome());
33 }
34 // how to write a test for stochastic method?
35 for (int i=0; i<20; i++) {
36 ChromosomePair pair = ts.select(pop);
37 // the worst chromosome should NEVER be selected
38 Assert.assertTrue(pair.getFirst().getFitness() > 0);
39 Assert.assertTrue(pair.getSecond().getFitness() > 0);
40 }
41 }
42
43 private static final class DummyChromosome extends Chromosome {
44 private final int fitness;
45
46 DummyChromosome() {
47 this.fitness = counter;
48 counter++;
49 }
50
51 @Override
52 public double fitness() {
53 return this.fitness;
54 }
55 }
56 }