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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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import java.util.Arrays; |
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import java.util.List; |
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import java.util.SplittableRandom; |
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import java.util.concurrent.atomic.AtomicInteger; |
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import java.util.concurrent.atomic.LongAdder; |
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import java.lang.reflect.Method; |
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import java.util.function.Predicate; |
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import java.util.stream.Collectors; |
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|
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import junit.framework.Test; |
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import junit.framework.TestSuite; |
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|
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public class SplittableRandomTest extends JSR166TestCase { |
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|
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public static void main(String[] args) { |
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main(suite(), args); |
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} |
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public static Test suite() { |
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return new TestSuite(SplittableRandomTest.class); |
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} |
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|
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/* |
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* Testing coverage notes: |
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* |
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* 1. Many of the test methods are adapted from ThreadLocalRandomTest. |
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* |
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* 2. These tests do not check for random number generator quality. |
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* But we check for minimal API compliance by requiring that |
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* repeated calls to nextX methods, up to NCALLS tries, produce at |
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* least two distinct results. (In some possible universe, a |
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* "correct" implementation might fail, but the odds are vastly |
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* less than that of encountering a hardware failure while running |
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* the test.) For bounded nextX methods, we sample various |
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* intervals across multiples of primes. In other tests, we repeat |
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* under REPS different values. |
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*/ |
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|
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// max numbers of calls to detect getting stuck on one value |
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static final int NCALLS = 10000; |
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|
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// max sampled int bound |
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static final int MAX_INT_BOUND = (1 << 26); |
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|
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// max sampled long bound |
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static final long MAX_LONG_BOUND = (1L << 40); |
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|
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// Number of replications for other checks |
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static final int REPS = |
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Integer.getInteger("SplittableRandomTest.reps", 4); |
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|
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/** |
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* Repeated calls to nextInt produce at least two distinct results |
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*/ |
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public void testNextInt() { |
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SplittableRandom sr = new SplittableRandom(); |
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int f = sr.nextInt(); |
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int i = 0; |
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while (i < NCALLS && sr.nextInt() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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|
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/** |
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* Repeated calls to nextLong produce at least two distinct results |
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*/ |
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public void testNextLong() { |
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SplittableRandom sr = new SplittableRandom(); |
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long f = sr.nextLong(); |
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int i = 0; |
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while (i < NCALLS && sr.nextLong() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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|
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/** |
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* Repeated calls to nextDouble produce at least two distinct results |
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*/ |
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public void testNextDouble() { |
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SplittableRandom sr = new SplittableRandom(); |
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double f = sr.nextDouble(); |
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int i = 0; |
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while (i < NCALLS && sr.nextDouble() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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|
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/** |
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* Two SplittableRandoms created with the same seed produce the |
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* same values for nextLong. |
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*/ |
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public void testSeedConstructor() { |
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for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) { |
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SplittableRandom sr1 = new SplittableRandom(seed); |
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SplittableRandom sr2 = new SplittableRandom(seed); |
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for (int i = 0; i < REPS; ++i) |
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assertEquals(sr1.nextLong(), sr2.nextLong()); |
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} |
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} |
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|
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/** |
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* A SplittableRandom produced by split() of a default-constructed |
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* SplittableRandom generates a different sequence |
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*/ |
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public void testSplit1() { |
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SplittableRandom sr = new SplittableRandom(); |
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for (int reps = 0; reps < REPS; ++reps) { |
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SplittableRandom sc = sr.split(); |
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int i = 0; |
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while (i < NCALLS && sr.nextLong() == sc.nextLong()) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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} |
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|
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/** |
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* A SplittableRandom produced by split() of a seeded-constructed |
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* SplittableRandom generates a different sequence |
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*/ |
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public void testSplit2() { |
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SplittableRandom sr = new SplittableRandom(12345); |
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for (int reps = 0; reps < REPS; ++reps) { |
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SplittableRandom sc = sr.split(); |
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int i = 0; |
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while (i < NCALLS && sr.nextLong() == sc.nextLong()) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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} |
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|
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/** |
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* nextInt(non-positive) throws IllegalArgumentException |
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*/ |
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public void testNextIntBoundNonPositive() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextInt(-17), |
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() -> sr.nextInt(0), |
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() -> sr.nextInt(Integer.MIN_VALUE)); |
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} |
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|
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/** |
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* nextInt(least >= bound) throws IllegalArgumentException |
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*/ |
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public void testNextIntBadBounds() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextInt(17, 2), |
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() -> sr.nextInt(-42, -42), |
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() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE)); |
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} |
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|
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/** |
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* nextInt(bound) returns 0 <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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public void testNextIntBounded() { |
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SplittableRandom sr = new SplittableRandom(); |
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for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1)); |
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// sample bound space across prime number increments |
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for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) { |
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int f = sr.nextInt(bound); |
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assertTrue(0 <= f && f < bound); |
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int i = 0; |
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int j; |
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while (i < NCALLS && |
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(j = sr.nextInt(bound)) == f) { |
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assertTrue(0 <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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|
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/** |
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* nextInt(least, bound) returns least <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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public void testNextIntBounded2() { |
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SplittableRandom sr = new SplittableRandom(); |
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for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) { |
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for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) { |
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int f = sr.nextInt(least, bound); |
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assertTrue(least <= f && f < bound); |
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int i = 0; |
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int j; |
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while (i < NCALLS && |
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(j = sr.nextInt(least, bound)) == f) { |
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assertTrue(least <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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} |
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|
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/** |
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* nextLong(non-positive) throws IllegalArgumentException |
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*/ |
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public void testNextLongBoundNonPositive() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextLong(-17L), |
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() -> sr.nextLong(0L), |
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() -> sr.nextLong(Long.MIN_VALUE)); |
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} |
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|
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/** |
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* nextLong(least >= bound) throws IllegalArgumentException |
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*/ |
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public void testNextLongBadBounds() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextLong(17L, 2L), |
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() -> sr.nextLong(-42L, -42L), |
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() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE)); |
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} |
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|
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/** |
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* nextLong(bound) returns 0 <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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public void testNextLongBounded() { |
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SplittableRandom sr = new SplittableRandom(); |
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for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L)); |
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for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) { |
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long f = sr.nextLong(bound); |
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assertTrue(0 <= f && f < bound); |
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int i = 0; |
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long j; |
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while (i < NCALLS && |
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(j = sr.nextLong(bound)) == f) { |
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assertTrue(0 <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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|
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/** |
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* nextLong(least, bound) returns least <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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public void testNextLongBounded2() { |
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SplittableRandom sr = new SplittableRandom(); |
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for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) { |
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for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) { |
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long f = sr.nextLong(least, bound); |
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assertTrue(least <= f && f < bound); |
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int i = 0; |
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long j; |
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while (i < NCALLS && |
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(j = sr.nextLong(least, bound)) == f) { |
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assertTrue(least <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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} |
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|
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/** |
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* nextDouble(non-positive) throws IllegalArgumentException |
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*/ |
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public void testNextDoubleBoundNonPositive() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextDouble(-17.0d), |
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() -> sr.nextDouble(0.0d), |
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() -> sr.nextDouble(-Double.MIN_VALUE), |
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() -> sr.nextDouble(Double.NEGATIVE_INFINITY), |
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() -> sr.nextDouble(Double.NaN)); |
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} |
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|
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/** |
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* nextDouble(! (least < bound)) throws IllegalArgumentException |
287 |
*/ |
288 |
public void testNextDoubleBadBounds() { |
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SplittableRandom sr = new SplittableRandom(); |
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assertThrows( |
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IllegalArgumentException.class, |
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() -> sr.nextDouble(17.0d, 2.0d), |
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() -> sr.nextDouble(-42.0d, -42.0d), |
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() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE), |
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() -> sr.nextDouble(Double.NaN, 0.0d), |
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() -> sr.nextDouble(0.0d, Double.NaN)); |
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} |
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|
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// TODO: Test infinite bounds! |
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//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d), |
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//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY), |
302 |
|
303 |
/** |
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* nextDouble(least, bound) returns least <= value < bound; |
305 |
* repeated calls produce at least two distinct results |
306 |
*/ |
307 |
public void testNextDoubleBounded2() { |
308 |
SplittableRandom sr = new SplittableRandom(); |
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for (double least = 0.0001; least < 1.0e20; least *= 8) { |
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for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) { |
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double f = sr.nextDouble(least, bound); |
312 |
assertTrue(least <= f && f < bound); |
313 |
int i = 0; |
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double j; |
315 |
while (i < NCALLS && |
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(j = sr.nextDouble(least, bound)) == f) { |
317 |
assertTrue(least <= j && j < bound); |
318 |
++i; |
319 |
} |
320 |
assertTrue(i < NCALLS); |
321 |
} |
322 |
} |
323 |
} |
324 |
|
325 |
/** |
326 |
* Invoking sized ints, long, doubles, with negative sizes throws |
327 |
* IllegalArgumentException |
328 |
*/ |
329 |
public void testBadStreamSize() { |
330 |
SplittableRandom r = new SplittableRandom(); |
331 |
assertThrows( |
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IllegalArgumentException.class, |
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() -> { java.util.stream.IntStream x = r.ints(-1L); }, |
334 |
() -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); }, |
335 |
() -> { java.util.stream.LongStream x = r.longs(-1L); }, |
336 |
() -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); }, |
337 |
() -> { java.util.stream.DoubleStream x = r.doubles(-1L); }, |
338 |
() -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); }); |
339 |
} |
340 |
|
341 |
/** |
342 |
* Invoking bounded ints, long, doubles, with illegal bounds throws |
343 |
* IllegalArgumentException |
344 |
*/ |
345 |
public void testBadStreamBounds() { |
346 |
SplittableRandom r = new SplittableRandom(); |
347 |
assertThrows( |
348 |
IllegalArgumentException.class, |
349 |
() -> { java.util.stream.IntStream x = r.ints(2, 1); }, |
350 |
() -> { java.util.stream.IntStream x = r.ints(10, 42, 42); }, |
351 |
() -> { java.util.stream.LongStream x = r.longs(-1L, -1L); }, |
352 |
() -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); }, |
353 |
() -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); }, |
354 |
() -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); }); |
355 |
} |
356 |
|
357 |
/** |
358 |
* A parallel sized stream of ints generates the given number of values |
359 |
*/ |
360 |
public void testIntsCount() { |
361 |
LongAdder counter = new LongAdder(); |
362 |
SplittableRandom r = new SplittableRandom(); |
363 |
long size = 0; |
364 |
for (int reps = 0; reps < REPS; ++reps) { |
365 |
counter.reset(); |
366 |
r.ints(size).parallel().forEach(x -> counter.increment()); |
367 |
assertEquals(size, counter.sum()); |
368 |
size += 524959; |
369 |
} |
370 |
} |
371 |
|
372 |
/** |
373 |
* A parallel sized stream of longs generates the given number of values |
374 |
*/ |
375 |
public void testLongsCount() { |
376 |
LongAdder counter = new LongAdder(); |
377 |
SplittableRandom r = new SplittableRandom(); |
378 |
long size = 0; |
379 |
for (int reps = 0; reps < REPS; ++reps) { |
380 |
counter.reset(); |
381 |
r.longs(size).parallel().forEach(x -> counter.increment()); |
382 |
assertEquals(size, counter.sum()); |
383 |
size += 524959; |
384 |
} |
385 |
} |
386 |
|
387 |
/** |
388 |
* A parallel sized stream of doubles generates the given number of values |
389 |
*/ |
390 |
public void testDoublesCount() { |
391 |
LongAdder counter = new LongAdder(); |
392 |
SplittableRandom r = new SplittableRandom(); |
393 |
long size = 0; |
394 |
for (int reps = 0; reps < REPS; ++reps) { |
395 |
counter.reset(); |
396 |
r.doubles(size).parallel().forEach(x -> counter.increment()); |
397 |
assertEquals(size, counter.sum()); |
398 |
size += 524959; |
399 |
} |
400 |
} |
401 |
|
402 |
/** |
403 |
* Each of a parallel sized stream of bounded ints is within bounds |
404 |
*/ |
405 |
public void testBoundedInts() { |
406 |
AtomicInteger fails = new AtomicInteger(0); |
407 |
SplittableRandom r = new SplittableRandom(); |
408 |
long size = 12345L; |
409 |
for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) { |
410 |
for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) { |
411 |
final int lo = least, hi = bound; |
412 |
r.ints(size, lo, hi).parallel().forEach( |
413 |
x -> { |
414 |
if (x < lo || x >= hi) |
415 |
fails.getAndIncrement(); }); |
416 |
} |
417 |
} |
418 |
assertEquals(0, fails.get()); |
419 |
} |
420 |
|
421 |
/** |
422 |
* Each of a parallel sized stream of bounded longs is within bounds |
423 |
*/ |
424 |
public void testBoundedLongs() { |
425 |
AtomicInteger fails = new AtomicInteger(0); |
426 |
SplittableRandom r = new SplittableRandom(); |
427 |
long size = 123L; |
428 |
for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) { |
429 |
for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) { |
430 |
final long lo = least, hi = bound; |
431 |
r.longs(size, lo, hi).parallel().forEach( |
432 |
x -> { |
433 |
if (x < lo || x >= hi) |
434 |
fails.getAndIncrement(); }); |
435 |
} |
436 |
} |
437 |
assertEquals(0, fails.get()); |
438 |
} |
439 |
|
440 |
/** |
441 |
* Each of a parallel sized stream of bounded doubles is within bounds |
442 |
*/ |
443 |
public void testBoundedDoubles() { |
444 |
AtomicInteger fails = new AtomicInteger(0); |
445 |
SplittableRandom r = new SplittableRandom(); |
446 |
long size = 456; |
447 |
for (double least = 0.00011; least < 1.0e20; least *= 9) { |
448 |
for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) { |
449 |
final double lo = least, hi = bound; |
450 |
r.doubles(size, lo, hi).parallel().forEach( |
451 |
x -> { |
452 |
if (x < lo || x >= hi) |
453 |
fails.getAndIncrement(); }); |
454 |
} |
455 |
} |
456 |
assertEquals(0, fails.get()); |
457 |
} |
458 |
|
459 |
/** |
460 |
* A parallel unsized stream of ints generates at least 100 values |
461 |
*/ |
462 |
public void testUnsizedIntsCount() { |
463 |
LongAdder counter = new LongAdder(); |
464 |
SplittableRandom r = new SplittableRandom(); |
465 |
long size = 100; |
466 |
r.ints().limit(size).parallel().forEach(x -> counter.increment()); |
467 |
assertEquals(size, counter.sum()); |
468 |
} |
469 |
|
470 |
/** |
471 |
* A parallel unsized stream of longs generates at least 100 values |
472 |
*/ |
473 |
public void testUnsizedLongsCount() { |
474 |
LongAdder counter = new LongAdder(); |
475 |
SplittableRandom r = new SplittableRandom(); |
476 |
long size = 100; |
477 |
r.longs().limit(size).parallel().forEach(x -> counter.increment()); |
478 |
assertEquals(size, counter.sum()); |
479 |
} |
480 |
|
481 |
/** |
482 |
* A parallel unsized stream of doubles generates at least 100 values |
483 |
*/ |
484 |
public void testUnsizedDoublesCount() { |
485 |
LongAdder counter = new LongAdder(); |
486 |
SplittableRandom r = new SplittableRandom(); |
487 |
long size = 100; |
488 |
r.doubles().limit(size).parallel().forEach(x -> counter.increment()); |
489 |
assertEquals(size, counter.sum()); |
490 |
} |
491 |
|
492 |
/** |
493 |
* A sequential unsized stream of ints generates at least 100 values |
494 |
*/ |
495 |
public void testUnsizedIntsCountSeq() { |
496 |
LongAdder counter = new LongAdder(); |
497 |
SplittableRandom r = new SplittableRandom(); |
498 |
long size = 100; |
499 |
r.ints().limit(size).forEach(x -> counter.increment()); |
500 |
assertEquals(size, counter.sum()); |
501 |
} |
502 |
|
503 |
/** |
504 |
* A sequential unsized stream of longs generates at least 100 values |
505 |
*/ |
506 |
public void testUnsizedLongsCountSeq() { |
507 |
LongAdder counter = new LongAdder(); |
508 |
SplittableRandom r = new SplittableRandom(); |
509 |
long size = 100; |
510 |
r.longs().limit(size).forEach(x -> counter.increment()); |
511 |
assertEquals(size, counter.sum()); |
512 |
} |
513 |
|
514 |
/** |
515 |
* A sequential unsized stream of doubles generates at least 100 values |
516 |
*/ |
517 |
public void testUnsizedDoublesCountSeq() { |
518 |
LongAdder counter = new LongAdder(); |
519 |
SplittableRandom r = new SplittableRandom(); |
520 |
long size = 100; |
521 |
r.doubles().limit(size).forEach(x -> counter.increment()); |
522 |
assertEquals(size, counter.sum()); |
523 |
} |
524 |
|
525 |
/** |
526 |
* SplittableRandom should implement most of Random's public methods |
527 |
*/ |
528 |
public void testShouldImplementMostRandomMethods() throws Throwable { |
529 |
Predicate<Method> wasForgotten = method -> { |
530 |
String name = method.getName(); |
531 |
// some methods deliberately not implemented |
532 |
if (name.equals("setSeed")) return false; |
533 |
if (name.equals("nextFloat")) return false; |
534 |
if (name.equals("nextGaussian")) return false; |
535 |
try { |
536 |
SplittableRandom.class.getMethod( |
537 |
method.getName(), method.getParameterTypes()); |
538 |
} catch (ReflectiveOperationException ex) { |
539 |
return true; |
540 |
} |
541 |
return false; |
542 |
}; |
543 |
List<Method> forgotten = |
544 |
Arrays.stream(java.util.Random.class.getMethods()) |
545 |
.filter(wasForgotten) |
546 |
.collect(Collectors.toList()); |
547 |
if (!forgotten.isEmpty()) |
548 |
throw new AssertionError("Please implement: " + forgotten); |
549 |
} |
550 |
|
551 |
/** |
552 |
* Repeated calls to nextBytes produce at least values of different signs for every byte |
553 |
*/ |
554 |
public void testNextBytes() { |
555 |
SplittableRandom sr = new SplittableRandom(); |
556 |
int n = sr.nextInt(1, 20); |
557 |
byte[] bytes = new byte[n]; |
558 |
outer: |
559 |
for (int i = 0; i < n; i++) { |
560 |
for (int tries = NCALLS; tries-->0; ) { |
561 |
byte before = bytes[i]; |
562 |
sr.nextBytes(bytes); |
563 |
byte after = bytes[i]; |
564 |
if (after * before < 0) |
565 |
continue outer; |
566 |
} |
567 |
fail("not enough variation in random bytes"); |
568 |
} |
569 |
} |
570 |
|
571 |
/** |
572 |
* Filling an empty array with random bytes succeeds without effect. |
573 |
*/ |
574 |
public void testNextBytes_emptyArray() { |
575 |
new SplittableRandom().nextBytes(new byte[0]); |
576 |
} |
577 |
|
578 |
public void testNextBytes_nullArray() { |
579 |
try { |
580 |
new SplittableRandom().nextBytes(null); |
581 |
shouldThrow(); |
582 |
} catch (NullPointerException success) {} |
583 |
} |
584 |
|
585 |
} |