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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  /**
26   * This test checks the {@link PoissonSampler} can be created
27   * from a saved state.
28   */
29  class PoissonSamplerTest {
30      /**
31       * Test the SharedStateSampler implementation with a mean below 40.
32       */
33      @Test
34      void testSharedStateSamplerWithSmallMean() {
35          testSharedStateSampler(34.5);
36      }
37  
38      /**
39       * Test the SharedStateSampler implementation with a mean above 40.
40       */
41      @Test
42      void testSharedStateSamplerWithLargeMean() {
43          testSharedStateSampler(67.8);
44      }
45  
46      /**
47       * Test the SharedStateSampler implementation.
48       *
49       * @param mean Mean.
50       */
51      private static void testSharedStateSampler(double mean) {
52          final UniformRandomProvider rng1 = RandomAssert.seededRNG();
53          final UniformRandomProvider rng2 = RandomAssert.seededRNG();
54          // Use instance constructor not factory constructor to exercise 1.X public API
55          final SharedStateDiscreteSampler sampler1 =
56              new PoissonSampler(rng1, mean);
57          final SharedStateDiscreteSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
58          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
59      }
60  
61      /**
62       * Test the toString method. This is added to ensure coverage as the factory constructor
63       * used in other tests does not create an instance of the wrapper class.
64       */
65      @Test
66      void testToString() {
67          final UniformRandomProvider rng = RandomAssert.seededRNG();
68          Assertions.assertTrue(new PoissonSampler(rng, 1.23).toString().toLowerCase().contains("poisson"));
69      }
70  }