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.math.stat.descriptive.moment;
18  
19  import junit.framework.Test;
20  import junit.framework.TestSuite;
21  
22  import org.apache.commons.math.stat.descriptive.StorelessUnivariateStatisticAbstractTest;
23  import org.apache.commons.math.stat.descriptive.UnivariateStatistic;
24  
25  /**
26   * Test cases for the {@link UnivariateStatistic} class.
27   * @version $Revision: 480442 $ $Date: 2006-11-29 00:21:22 -0700 (Wed, 29 Nov 2006) $
28   */
29  public class GeometricMeanTest extends StorelessUnivariateStatisticAbstractTest{
30  
31      protected GeometricMean stat;
32      
33      /**
34       * @param name
35       */
36      public GeometricMeanTest(String name) {
37          super(name);
38      }
39  
40      public static Test suite() {
41          TestSuite suite = new TestSuite(GeometricMeanTest.class);
42          suite.setName("Mean  Tests");
43          return suite;
44      }
45      
46      /* (non-Javadoc)
47       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#getUnivariateStatistic()
48       */
49      public UnivariateStatistic getUnivariateStatistic() {
50          return new GeometricMean();
51      }
52  
53      /* (non-Javadoc)
54       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#expectedValue()
55       */
56      public double expectedValue() {
57          return this.geoMean;
58      }
59      
60      public void testSpecialValues() {
61          GeometricMean mean = new GeometricMean();
62          // empty
63          assertTrue(Double.isNaN(mean.getResult()));
64          
65          // finite data
66          mean.increment(1d);
67          assertFalse(Double.isNaN(mean.getResult()));
68          
69          // add 0 -- makes log sum blow to minus infinity, should make 0
70          mean.increment(0d);
71          assertEquals(0d, mean.getResult(), 0);
72          
73          // add positive infinity - note the minus infinity above
74          mean.increment(Double.POSITIVE_INFINITY);
75          assertTrue(Double.isNaN(mean.getResult()));
76          
77          // clear
78          mean.clear();
79          assertTrue(Double.isNaN(mean.getResult()));
80          
81          // positive infinity by itself
82          mean.increment(Double.POSITIVE_INFINITY);
83          assertEquals(Double.POSITIVE_INFINITY, mean.getResult(), 0);
84          
85          // negative value -- should make NaN
86          mean.increment(-2d);
87          assertTrue(Double.isNaN(mean.getResult()));
88      }
89  
90  }