View Javadoc
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.apache.commons.rng.simple.RandomSource;
22  import org.junit.Assert;
23  import org.junit.Test;
24  
25  
26  /**
27   * This test checks the {@link PoissonSampler} can be created
28   * from a saved state.
29   */
30  public class PoissonSamplerTest {
31      /**
32       * Test the SharedStateSampler implementation with a mean below 40.
33       */
34      @Test
35      public void testSharedStateSamplerWithSmallMean() {
36          testSharedStateSampler(34.5);
37      }
38  
39      /**
40       * Test the SharedStateSampler implementation with a mean above 40.
41       */
42      @Test
43      public void testSharedStateSamplerWithLargeMean() {
44          testSharedStateSampler(67.8);
45      }
46  
47      /**
48       * Test the SharedStateSampler implementation.
49       *
50       * @param mean Mean.
51       */
52      private static void testSharedStateSampler(double mean) {
53          final UniformRandomProvider rng1 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
54          final UniformRandomProvider rng2 = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
55          // Use instance constructor not factory constructor to exercise 1.X public API
56          final SharedStateDiscreteSampler sampler1 =
57              new PoissonSampler(rng1, mean);
58          final SharedStateDiscreteSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
59          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
60      }
61  
62      /**
63       * Test the toString method. This is added to ensure coverage as the factory constructor
64       * used in other tests does not create an instance of the wrapper class.
65       */
66      @Test
67      public void testToString() {
68          final UniformRandomProvider rng = RandomSource.create(RandomSource.SPLIT_MIX_64, 0L);
69          Assert.assertTrue(new PoissonSampler(rng, 1.23).toString().toLowerCase().contains("poisson"));
70      }
71  }