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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 org.hipparchus.distribution.RealDistribution;
26  import org.junit.jupiter.api.BeforeEach;
27  import org.junit.jupiter.api.Test;
28  
29  import static org.junit.jupiter.api.Assertions.assertEquals;
30  
31  /**
32   * Test cases for ConstantRealDistribution.
33   */
34  public class ConstantRealDistributionTest extends RealDistributionAbstractTest {
35  
36      // --- Override tolerance -------------------------------------------------
37  
38      @BeforeEach
39      @Override
40      public void setUp() {
41          super.setUp();
42          setTolerance(0);
43      }
44  
45      //--- Implementations for abstract methods --------------------------------
46  
47      /** Creates the default uniform real distribution instance to use in tests. */
48      @Override
49      public ConstantRealDistribution makeDistribution() {
50          return new ConstantRealDistribution(1);
51      }
52  
53      /** Creates the default cumulative probability distribution test input values */
54      @Override
55      public double[] makeCumulativeTestPoints() {
56          return new double[] { 0, 0.5, 1 };
57      }
58  
59      /** Creates the default cumulative probability distribution test expected values */
60      @Override
61      public double[] makeCumulativeTestValues() {
62          return new double[] { 0, 0, 1 };
63      }
64  
65      /** Creates the default probability density test expected values */
66      @Override
67      public double[] makeDensityTestValues() {
68          return new double[] { 0, 0, 1 };
69      }
70  
71      /** Override default test, verifying that inverse cum is constant */
72      @Override
73      @Test
74      public void testInverseCumulativeProbabilities() {
75          RealDistribution dist = getDistribution();
76          for (double x : getCumulativeTestValues()) {
77              assertEquals(1,dist.inverseCumulativeProbability(x), 0);
78          }
79      }
80  
81      //--- Additional test cases -----------------------------------------------
82  
83      @Test
84      void testMeanVariance() {
85          ConstantRealDistribution dist;
86  
87          dist = new ConstantRealDistribution(-1);
88          assertEquals(-1, dist.getNumericalMean(), 0d);
89          assertEquals(0, dist.getNumericalVariance(), 0d);
90      }
91  
92  }