1   /*
2    * Copyright 2003-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.math.stat.descriptive.summary;
17  
18  import junit.framework.Test;
19  import junit.framework.TestSuite;
20  
21  import org.apache.commons.math.stat.descriptive.StorelessUnivariateStatisticAbstractTest;
22  import org.apache.commons.math.stat.descriptive.UnivariateStatistic;
23  
24  /**
25   * Test cases for the {@link UnivariateStatistic} class.
26   * @version $Revision: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (Sat, 26 Feb 2005) $
27   */
28  public class SumLogTest extends StorelessUnivariateStatisticAbstractTest{
29  
30      protected SumOfLogs stat;
31      
32      /**
33       * @param name
34       */
35      public SumLogTest(String name) {
36          super(name);
37      }
38  
39      public static Test suite() {
40          TestSuite suite = new TestSuite(SumLogTest.class);
41          suite.setName("SumLog Tests");
42          return suite;
43      }
44      
45      /* (non-Javadoc)
46       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#getUnivariateStatistic()
47       */
48      public UnivariateStatistic getUnivariateStatistic() {        
49          return new SumOfLogs();
50      }
51  
52      /* (non-Javadoc)
53       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#expectedValue()
54       */
55      public double expectedValue() {
56          return this.sumLog;
57      }
58      
59      public void testSpecialValues() {
60          SumOfLogs sum = new SumOfLogs();
61          // empty
62          assertTrue(Double.isNaN(sum.getResult()));
63          
64          // finite data
65          sum.increment(1d);
66          assertFalse(Double.isNaN(sum.getResult()));
67          
68          // add negative infinity
69          sum.increment(0d);
70          assertEquals(Double.NEGATIVE_INFINITY, sum.getResult(), 0);
71          
72          // add positive infinity -- should make NaN
73          sum.increment(Double.POSITIVE_INFINITY);
74          assertTrue(Double.isNaN(sum.getResult()));
75          
76          // clear
77          sum.clear();
78          assertTrue(Double.isNaN(sum.getResult()));
79          
80          // positive infinity by itself
81          sum.increment(Double.POSITIVE_INFINITY);
82          assertEquals(Double.POSITIVE_INFINITY, sum.getResult(), 0);
83          
84          // negative value -- should make NaN
85          sum.increment(-2d);
86          assertTrue(Double.isNaN(sum.getResult()));
87      }
88  
89  }