| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.rng.simple; |
| |
| import java.util.Random; |
| |
| import org.apache.commons.rng.UniformRandomProvider; |
| import org.apache.commons.rng.core.source64.LongProvider; |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| /** |
| * Tests for the {@link JDKRandomWrapper} class. |
| */ |
| public class JDKRandomWrapperTest { |
| /** |
| * Test all the methods shared by Random and UniformRandomProvider are equivalent. |
| */ |
| @Test |
| public void testJDKRandomEquivalence() { |
| // Initialize. |
| final long seed = RandomSource.createLong(); |
| final Random rng1 = new Random(seed); |
| final UniformRandomProvider rng2 = new JDKRandomWrapper(new Random(seed)); |
| checkSameSequence(rng1, rng2); |
| } |
| |
| /** |
| * Ensure that both generators produce the same sequences. |
| * |
| * @param rng1 RNG. |
| * @param rng2 RNG. |
| */ |
| private static void checkSameSequence(Random rng1, |
| UniformRandomProvider rng2) { |
| for (int i = 0; i < 4; i++) { |
| Assert.assertEquals(rng1.nextInt(), |
| rng2.nextInt()); |
| } |
| for (int i = 0; i < 7; i++) { |
| Assert.assertEquals(rng1.nextLong(), |
| rng2.nextLong()); |
| } |
| for (int i = 0; i < 9; i++) { |
| Assert.assertEquals(rng1.nextFloat(), |
| rng2.nextFloat(), |
| 0f); |
| } |
| for (int i = 0; i < 12; i++) { |
| Assert.assertEquals(rng1.nextDouble(), |
| rng2.nextDouble(), |
| 0d); |
| } |
| for (int i = 0; i < 18; i++) { |
| Assert.assertEquals(rng1.nextBoolean(), |
| rng2.nextBoolean()); |
| } |
| for (int i = 0; i < 19; i++) { |
| final int max = i + 123456; |
| Assert.assertEquals(rng1.nextInt(max), |
| rng2.nextInt(max)); |
| } |
| |
| final int len = 233; |
| final byte[] store1 = new byte[len]; |
| final byte[] store2 = new byte[len]; |
| rng1.nextBytes(store1); |
| rng2.nextBytes(store2); |
| for (int i = 0; i < len; i++) { |
| Assert.assertEquals(store1[i], |
| store2[i]); |
| } |
| } |
| |
| /** |
| * Test {@link UniformRandomProvider#nextLong(long)} matches that from the core |
| * BaseProvider implementation. |
| */ |
| @Test |
| public void testNextLongInRange() { |
| final long seed = RandomSource.createLong(); |
| // This will use the RNG core BaseProvider implementation. |
| // Use a LongProvider to directly use the Random::nextLong method |
| // which is different from IntProvider::nextLong. |
| final UniformRandomProvider rng1 = new LongProvider() { |
| private final Random random = new Random(seed); |
| |
| @Override |
| public long next() { |
| return random.nextLong(); |
| } |
| }; |
| final UniformRandomProvider rng2 = new JDKRandomWrapper(new Random(seed)); |
| |
| // Test cases |
| // 1 : Smallest range |
| // 256 : Integer power of 2 |
| // 56757 : Integer range |
| // 1L << 32 : Non-integer power of 2 |
| // (1L << 62) + 1 : Worst case for rejection rate for the algorithm. |
| // Reject probability is approximately 0.5 thus the test hits |
| // all code paths. |
| for (final long max : new long[] {1, 256, 56757, 1L << 32, (1L << 62) + 1}) { |
| for (int i = 0; i < 10; i++) { |
| Assert.assertEquals(rng1.nextLong(max), |
| rng2.nextLong(max)); |
| } |
| } |
| } |
| |
| @Test(expected = IllegalArgumentException.class) |
| public void testNextLongInRangeThrows() { |
| final UniformRandomProvider rng1 = new JDKRandomWrapper(new Random(5675767L)); |
| rng1.nextLong(0); |
| } |
| |
| /** |
| * Test the bytes created by {@link UniformRandomProvider#nextBytes(byte[], int, int)} matches |
| * {@link Random#nextBytes(byte[])}. |
| */ |
| @Test |
| public void testNextByteInRange() { |
| final long seed = RandomSource.createLong(); |
| final Random rng1 = new Random(seed); |
| final UniformRandomProvider rng2 = new JDKRandomWrapper(new Random(seed)); |
| |
| checkSameBytes(rng1, rng2, 1, 0, 1); |
| checkSameBytes(rng1, rng2, 100, 0, 100); |
| checkSameBytes(rng1, rng2, 100, 10, 90); |
| checkSameBytes(rng1, rng2, 245, 67, 34); |
| } |
| |
| /** |
| * Ensure that the bytes produced in a sub-range of a byte array by |
| * {@link UniformRandomProvider#nextBytes(byte[], int, int)} match the bytes created |
| * by the JDK {@link Random#nextBytes(byte[])}. |
| * |
| * @param rng1 JDK Random. |
| * @param rng2 RNG. |
| * @param size Size of byte array. |
| * @param start Index at which to start inserting the generated bytes. |
| * @param len Number of bytes to insert. |
| */ |
| private static void checkSameBytes(Random rng1, |
| UniformRandomProvider rng2, |
| int size, int start, int length) { |
| final byte[] store1 = new byte[length]; |
| final byte[] store2 = new byte[size]; |
| rng1.nextBytes(store1); |
| rng2.nextBytes(store2, start, length); |
| for (int i = 0; i < length; i++) { |
| Assert.assertEquals(store1[i], |
| store2[i + start]); |
| } |
| } |
| } |