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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    *      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.rng.sampling.distribution;
18  
19  import org.apache.commons.rng.UniformRandomProvider;
20  import org.apache.commons.rng.sampling.RandomAssert;
21  import org.junit.jupiter.api.Assertions;
22  import org.junit.jupiter.api.Test;
23  
24  /**
25   * Test for the {@link InverseTransformParetoSampler}. The tests hit edge cases for the sampler.
26   */
27  class InverseTransformParetoSamplerTest {
28      /**
29       * Test the constructor with a bad scale.
30       */
31      @Test
32      void testConstructorThrowsWithZeroScale() {
33          final UniformRandomProvider rng = RandomAssert.seededRNG();
34          final double scale = 0;
35          final double shape = 1;
36          Assertions.assertThrows(IllegalArgumentException.class,
37              () -> InverseTransformParetoSampler.of(rng, scale, shape));
38      }
39  
40      /**
41       * Test the constructor with a bad shape.
42       */
43      @Test
44      void testConstructorThrowsWithZeroShape() {
45          final UniformRandomProvider rng = RandomAssert.seededRNG();
46          final double scale = 1;
47          final double shape = 0;
48          Assertions.assertThrows(IllegalArgumentException.class,
49              () -> InverseTransformParetoSampler.of(rng, scale, shape));
50      }
51  
52      /**
53       * Test the SharedStateSampler implementation.
54       */
55      @Test
56      void testSharedStateSampler() {
57          final UniformRandomProvider rng1 = RandomAssert.seededRNG();
58          final UniformRandomProvider rng2 = RandomAssert.seededRNG();
59          final double scale = 1.23;
60          final double shape = 4.56;
61          final SharedStateContinuousSampler sampler1 =
62              InverseTransformParetoSampler.of(rng1, scale, shape);
63          final SharedStateContinuousSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
64          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
65      }
66  }