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.moment;
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 KurtosisTest extends StorelessUnivariateStatisticAbstractTest{
29  
30      protected Kurtosis stat;
31      
32      /**
33       * @param name
34       */
35      public KurtosisTest(String name) {
36          super(name);
37      }
38      
39      public static Test suite() {
40          TestSuite suite = new TestSuite(KurtosisTest.class);
41          suite.setName("Kurtosis  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 Kurtosis();
50      }
51  
52      /* (non-Javadoc)
53       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#expectedValue()
54       */
55      public double expectedValue() {
56          return this.kurt;
57      }
58      
59      /**
60       * Make sure Double.NaN is returned iff n < 4
61       *
62       */
63      public void testNaN() {
64          Kurtosis kurt = new Kurtosis();
65          assertTrue(Double.isNaN(kurt.getResult()));
66          kurt.increment(1d);
67          assertTrue(Double.isNaN(kurt.getResult()));
68          kurt.increment(1d);
69          assertTrue(Double.isNaN(kurt.getResult()));
70          kurt.increment(1d);
71          assertTrue(Double.isNaN(kurt.getResult()));
72          kurt.increment(1d);
73          assertFalse(Double.isNaN(kurt.getResult()));      
74      }
75  
76  }