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 * https://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
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.stat.descriptive.moment;
23
24 import static org.junit.Assert.assertFalse;
25 import static org.junit.Assert.assertTrue;
26
27 import org.hipparchus.stat.descriptive.StorelessUnivariateStatisticAbstractTest;
28 import org.junit.Test;
29
30 /**
31 * Test cases for the {@link Skewness} class.
32 */
33 public class SkewnessTest extends StorelessUnivariateStatisticAbstractTest{
34
35 @Override
36 public Skewness getUnivariateStatistic() {
37 return new Skewness();
38 }
39
40 @Override
41 public double expectedValue() {
42 return this.skew;
43 }
44
45 /**
46 * Make sure Double.NaN is returned iff n < 3
47 */
48 @Test
49 public void testNaN() {
50 Skewness skew = getUnivariateStatistic();
51 assertTrue(Double.isNaN(skew.getResult()));
52 skew.increment(1d);
53 assertTrue(Double.isNaN(skew.getResult()));
54 skew.increment(1d);
55 assertTrue(Double.isNaN(skew.getResult()));
56 skew.increment(1d);
57 assertFalse(Double.isNaN(skew.getResult()));
58 }
59
60 }