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 ProductTest extends StorelessUnivariateStatisticAbstractTest{
29  
30      protected Product stat;
31      
32      /**
33       * @param name
34       */
35      public ProductTest(String name) {
36          super(name);
37      }
38  
39      public static Test suite() {
40          TestSuite suite = new TestSuite(ProductTest.class);
41          suite.setName("Product 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 Product();
50      }
51  
52      public double getTolerance() {
53          return 10E8;    //sic -- big absolute error due to only 15 digits of accuracy in double
54      }
55      
56      /* (non-Javadoc)
57       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#expectedValue()
58       */
59      public double expectedValue() {
60          return this.product;
61      }
62      
63      public void testSpecialValues() {
64          Product product = new Product();
65          assertTrue(Double.isNaN(product.getResult()));
66          product.increment(1);
67          assertEquals(1, product.getResult(), 0);
68          product.increment(Double.POSITIVE_INFINITY);
69          assertEquals(Double.POSITIVE_INFINITY, product.getResult(), 0);
70          product.increment(Double.NEGATIVE_INFINITY);
71          assertEquals(Double.NEGATIVE_INFINITY, product.getResult(), 0);
72          product.increment(Double.NaN);
73          assertTrue(Double.isNaN(product.getResult())); 
74          product.increment(1);
75          assertTrue(Double.isNaN(product.getResult())); 
76      }
77  
78  }