src/test/java/org/apache/commons/math3/genetics/FixedElapsedTimeTest.java

/*
 * 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.math3.genetics;

import java.util.Iterator;
import java.util.concurrent.TimeUnit;

import org.apache.commons.math3.util.FastMath;
import org.junit.Assert;
import org.junit.Test;

public class FixedElapsedTimeTest {

    @Test
    public void testIsSatisfied() {
        final Population pop = new Population() {
            public void addChromosome(final Chromosome chromosome) {
                // unimportant
            }
            public Chromosome getFittestChromosome() {
                // unimportant
                return null;
            }
            public int getPopulationLimit() {
                // unimportant
                return 0;
            }
            public int getPopulationSize() {
                // unimportant
                return 0;
            }
            public Population nextGeneration() {
                // unimportant
                return null;
            }
            public Iterator<Chromosome> iterator() {
                // unimportant
                return null;
            }
        };

        final long start = System.nanoTime();
        final long duration = 3;
        final FixedElapsedTime tec = new FixedElapsedTime(duration, TimeUnit.SECONDS);

        while (!tec.isSatisfied(pop)) {
            try {
                Thread.sleep(50);
            } catch (InterruptedException e) {
                // ignore
            }
        }

        final long end = System.nanoTime();
        final long elapsedTime = end - start;
        final long diff = FastMath.abs(elapsedTime - TimeUnit.SECONDS.toNanos(duration));

        Assert.assertTrue(diff < TimeUnit.MILLISECONDS.toNanos(100));
    }
}