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 {@link ZigguratNormalizedGaussianSampler}.
26 */
27 class ZigguratNormalizedGaussianSamplerTest {
28 // Cf. RNG-56
29 @Test
30 void testInfiniteLoop() {
31 // A bad implementation whose only purpose is to force access
32 // to the rarest branch.
33 // nextLong() returns Long.MAX_VALUE
34 final UniformRandomProvider bad = () -> Long.MAX_VALUE;
35
36 // Infinite loop (in v1.1).
37 final ZigguratNormalizedGaussianSampler sampler = new ZigguratNormalizedGaussianSampler(bad);
38 Assertions.assertThrows(StackOverflowError.class,
39 () -> sampler.sample());
40 }
41
42 /**
43 * Test the SharedStateSampler implementation.
44 */
45 @Test
46 void testSharedStateSampler() {
47 final UniformRandomProvider rng1 = RandomAssert.seededRNG();
48 final UniformRandomProvider rng2 = RandomAssert.seededRNG();
49 final SharedStateContinuousSampler sampler1 =
50 ZigguratNormalizedGaussianSampler.<ZigguratNormalizedGaussianSampler>of(rng1);
51 final SharedStateContinuousSampler sampler2 = sampler1.withUniformRandomProvider(rng2);
52 RandomAssert.assertProduceSameSequence(sampler1, sampler2);
53 }
54 }