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
23 package org.hipparchus.distribution.continuous;
24
25 import static org.junit.Assert.assertEquals;
26
27 import org.hipparchus.distribution.RealDistribution;
28 import org.junit.Test;
29
30 /**
31 * Test cases for ConstantRealDistribution.
32 */
33 public class ConstantRealDistributionTest extends RealDistributionAbstractTest {
34
35 // --- Override tolerance -------------------------------------------------
36
37 @Override
38 public void setUp() {
39 super.setUp();
40 setTolerance(0);
41 }
42
43 //--- Implementations for abstract methods --------------------------------
44
45 /** Creates the default uniform real distribution instance to use in tests. */
46 @Override
47 public ConstantRealDistribution makeDistribution() {
48 return new ConstantRealDistribution(1);
49 }
50
51 /** Creates the default cumulative probability distribution test input values */
52 @Override
53 public double[] makeCumulativeTestPoints() {
54 return new double[] { 0, 0.5, 1 };
55 }
56
57 /** Creates the default cumulative probability distribution test expected values */
58 @Override
59 public double[] makeCumulativeTestValues() {
60 return new double[] { 0, 0, 1 };
61 }
62
63 /** Creates the default probability density test expected values */
64 @Override
65 public double[] makeDensityTestValues() {
66 return new double[] { 0, 0, 1 };
67 }
68
69 /** Override default test, verifying that inverse cum is constant */
70 @Override
71 @Test
72 public void testInverseCumulativeProbabilities() {
73 RealDistribution dist = getDistribution();
74 for (double x : getCumulativeTestValues()) {
75 assertEquals(1,dist.inverseCumulativeProbability(x), 0);
76 }
77 }
78
79 //--- Additional test cases -----------------------------------------------
80
81 @Test
82 public void testMeanVariance() {
83 ConstantRealDistribution dist;
84
85 dist = new ConstantRealDistribution(-1);
86 assertEquals(dist.getNumericalMean(), -1, 0d);
87 assertEquals(dist.getNumericalVariance(), 0, 0d);
88 }
89
90 }