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.stat.descriptive.moment;
018    
019    import junit.framework.Test;
020    import junit.framework.TestSuite;
021    
022    import org.apache.commons.math.stat.descriptive.StorelessUnivariateStatisticAbstractTest;
023    import org.apache.commons.math.stat.descriptive.UnivariateStatistic;
024    
025    /**
026     * Test cases for the {@link UnivariateStatistic} class.
027     * @version $Revision: 762087 $ $Date: 2009-04-05 10:20:18 -0400 (Sun, 05 Apr 2009) $
028     */
029    public class GeometricMeanTest extends StorelessUnivariateStatisticAbstractTest{
030    
031        protected GeometricMean stat;
032        
033        /**
034         * @param name
035         */
036        public GeometricMeanTest(String name) {
037            super(name);
038        }
039    
040        public static Test suite() {
041            TestSuite suite = new TestSuite(GeometricMeanTest.class);
042            suite.setName("Mean  Tests");
043            return suite;
044        }
045        
046        /**
047         * {@inheritDoc}
048         */
049        @Override
050        public UnivariateStatistic getUnivariateStatistic() {
051            return new GeometricMean();
052        }
053    
054        /**
055         * {@inheritDoc}
056         */
057        @Override
058        public double expectedValue() {
059            return this.geoMean;
060        }
061        
062        public void testSpecialValues() {
063            GeometricMean mean = new GeometricMean();
064            // empty
065            assertTrue(Double.isNaN(mean.getResult()));
066            
067            // finite data
068            mean.increment(1d);
069            assertFalse(Double.isNaN(mean.getResult()));
070            
071            // add 0 -- makes log sum blow to minus infinity, should make 0
072            mean.increment(0d);
073            assertEquals(0d, mean.getResult(), 0);
074            
075            // add positive infinity - note the minus infinity above
076            mean.increment(Double.POSITIVE_INFINITY);
077            assertTrue(Double.isNaN(mean.getResult()));
078            
079            // clear
080            mean.clear();
081            assertTrue(Double.isNaN(mean.getResult()));
082            
083            // positive infinity by itself
084            mean.increment(Double.POSITIVE_INFINITY);
085            assertEquals(Double.POSITIVE_INFINITY, mean.getResult(), 0);
086            
087            // negative value -- should make NaN
088            mean.increment(-2d);
089            assertTrue(Double.isNaN(mean.getResult()));
090        }
091    
092    }