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 KurtosisTest extends StorelessUnivariateStatisticAbstractTest{
30  
31      protected Kurtosis stat;
32      
33      /**
34       * @param name
35       */
36      public KurtosisTest(String name) {
37          super(name);
38      }
39      
40      public static Test suite() {
41          TestSuite suite = new TestSuite(KurtosisTest.class);
42          suite.setName("Kurtosis  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 Kurtosis();
51      }
52  
53      /* (non-Javadoc)
54       * @see org.apache.commons.math.stat.descriptive.UnivariateStatisticAbstractTest#expectedValue()
55       */
56      public double expectedValue() {
57          return this.kurt;
58      }
59      
60      /**
61       * Make sure Double.NaN is returned iff n < 4
62       *
63       */
64      public void testNaN() {
65          Kurtosis kurt = new Kurtosis();
66          assertTrue(Double.isNaN(kurt.getResult()));
67          kurt.increment(1d);
68          assertTrue(Double.isNaN(kurt.getResult()));
69          kurt.increment(1d);
70          assertTrue(Double.isNaN(kurt.getResult()));
71          kurt.increment(1d);
72          assertTrue(Double.isNaN(kurt.getResult()));
73          kurt.increment(1d);
74          assertFalse(Double.isNaN(kurt.getResult()));      
75      }
76  
77  }