test/jdk/java/util/concurrent/tck/SplittableRandomTest.java - platform/libcore - Git at Google

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 /*
  * This file is available under and governed by the GNU General Public
  * License version 2 only, as published by the Free Software Foundation.
  * However, the following notice accompanied the original version of this
  * file:
  *
  * Written by Doug Lea with assistance from members of JCP JSR-166
  * Expert Group and released to the public domain, as explained at
  * http://creativecommons.org/publicdomain/zero/1.0/
  */

 import java.util.Arrays;
 import java.util.List;
 import java.util.SplittableRandom;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.LongAdder;
 import java.lang.reflect.Method;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;

 import junit.framework.Test;
 import junit.framework.TestSuite;

 public class SplittableRandomTest extends JSR166TestCase {

     public static void main(String[] args) {
         main(suite(), args);
     }
     public static Test suite() {
         return new TestSuite(SplittableRandomTest.class);
     }

     /*
      * Testing coverage notes:
      *
      * 1. Many of the test methods are adapted from ThreadLocalRandomTest.
      *
      * 2. These tests do not check for random number generator quality.
      * But we check for minimal API compliance by requiring that
      * repeated calls to nextX methods, up to NCALLS tries, produce at
      * least two distinct results. (In some possible universe, a
      * "correct" implementation might fail, but the odds are vastly
      * less than that of encountering a hardware failure while running
      * the test.) For bounded nextX methods, we sample various
      * intervals across multiples of primes. In other tests, we repeat
      * under REPS different values.
      */

     // max numbers of calls to detect getting stuck on one value
     static final int NCALLS = 10000;

     // max sampled int bound
     static final int MAX_INT_BOUND = (1 << 26);

     // max sampled long bound
     static final long MAX_LONG_BOUND = (1L << 40);

     // Number of replications for other checks
     static final int REPS =
         Integer.getInteger("SplittableRandomTest.reps", 4);

     /**
      * Repeated calls to nextInt produce at least two distinct results
      */
     public void testNextInt() {
         SplittableRandom sr = new SplittableRandom();
         int f = sr.nextInt();
         int i = 0;
         while (i < NCALLS && sr.nextInt() == f)
             ++i;
         assertTrue(i < NCALLS);
     }

     /**
      * Repeated calls to nextLong produce at least two distinct results
      */
     public void testNextLong() {
         SplittableRandom sr = new SplittableRandom();
         long f = sr.nextLong();
         int i = 0;
         while (i < NCALLS && sr.nextLong() == f)
             ++i;
         assertTrue(i < NCALLS);
     }

     /**
      * Repeated calls to nextDouble produce at least two distinct results
      */
     public void testNextDouble() {
         SplittableRandom sr = new SplittableRandom();
         double f = sr.nextDouble();
         int i = 0;
         while (i < NCALLS && sr.nextDouble() == f)
             ++i;
         assertTrue(i < NCALLS);
     }

     /**
      * Two SplittableRandoms created with the same seed produce the
      * same values for nextLong.
      */
     public void testSeedConstructor() {
         for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
             SplittableRandom sr1 = new SplittableRandom(seed);
             SplittableRandom sr2 = new SplittableRandom(seed);
             for (int i = 0; i < REPS; ++i)
                 assertEquals(sr1.nextLong(), sr2.nextLong());
         }
     }

     /**
      * A SplittableRandom produced by split() of a default-constructed
      * SplittableRandom generates a different sequence
      */
     public void testSplit1() {
         SplittableRandom sr = new SplittableRandom();
         for (int reps = 0; reps < REPS; ++reps) {
             SplittableRandom sc = sr.split();
             int i = 0;
             while (i < NCALLS && sr.nextLong() == sc.nextLong())
                 ++i;
             assertTrue(i < NCALLS);
         }
     }

     /**
      * A SplittableRandom produced by split() of a seeded-constructed
      * SplittableRandom generates a different sequence
      */
     public void testSplit2() {
         SplittableRandom sr = new SplittableRandom(12345);
         for (int reps = 0; reps < REPS; ++reps) {
             SplittableRandom sc = sr.split();
             int i = 0;
             while (i < NCALLS && sr.nextLong() == sc.nextLong())
                 ++i;
             assertTrue(i < NCALLS);
         }
     }

     /**
      * nextInt(non-positive) throws IllegalArgumentException
      */
     public void testNextIntBoundNonPositive() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextInt(-17),
             () -> sr.nextInt(0),
             () -> sr.nextInt(Integer.MIN_VALUE),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * nextInt(least >= bound) throws IllegalArgumentException
      */
     public void testNextIntBadBounds() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextInt(17, 2),
             () -> sr.nextInt(-42, -42),
             () -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * nextInt(bound) returns 0 <= value < bound;
      * repeated calls produce at least two distinct results
      */
     public void testNextIntBounded() {
         SplittableRandom sr = new SplittableRandom();
         for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
         // sample bound space across prime number increments
         for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
             int f = sr.nextInt(bound);
             assertTrue(0 <= f && f < bound);
             int i = 0;
             int j;
             while (i < NCALLS &&
                    (j = sr.nextInt(bound)) == f) {
                 assertTrue(0 <= j && j < bound);
                 ++i;
             }
             assertTrue(i < NCALLS);
         }
     }

     /**
      * nextInt(least, bound) returns least <= value < bound;
      * repeated calls produce at least two distinct results
      */
     public void testNextIntBounded2() {
         SplittableRandom sr = new SplittableRandom();
         for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
             for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
                 int f = sr.nextInt(least, bound);
                 assertTrue(least <= f && f < bound);
                 int i = 0;
                 int j;
                 while (i < NCALLS &&
                        (j = sr.nextInt(least, bound)) == f) {
                     assertTrue(least <= j && j < bound);
                     ++i;
                 }
                 assertTrue(i < NCALLS);
             }
         }
     }

     /**
      * nextLong(non-positive) throws IllegalArgumentException
      */
     public void testNextLongBoundNonPositive() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextLong(-17L),
             () -> sr.nextLong(0L),
             () -> sr.nextLong(Long.MIN_VALUE),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * nextLong(least >= bound) throws IllegalArgumentException
      */
     public void testNextLongBadBounds() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextLong(17L, 2L),
             () -> sr.nextLong(-42L, -42L),
             () -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * nextLong(bound) returns 0 <= value < bound;
      * repeated calls produce at least two distinct results
      */
     public void testNextLongBounded() {
         SplittableRandom sr = new SplittableRandom();
         for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
         for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
             long f = sr.nextLong(bound);
             assertTrue(0 <= f && f < bound);
             int i = 0;
             long j;
             while (i < NCALLS &&
                    (j = sr.nextLong(bound)) == f) {
                 assertTrue(0 <= j && j < bound);
                 ++i;
             }
             assertTrue(i < NCALLS);
         }
     }

     /**
      * nextLong(least, bound) returns least <= value < bound;
      * repeated calls produce at least two distinct results
      */
     public void testNextLongBounded2() {
         SplittableRandom sr = new SplittableRandom();
         for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
             for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
                 long f = sr.nextLong(least, bound);
                 assertTrue(least <= f && f < bound);
                 int i = 0;
                 long j;
                 while (i < NCALLS &&
                        (j = sr.nextLong(least, bound)) == f) {
                     assertTrue(least <= j && j < bound);
                     ++i;
                 }
                 assertTrue(i < NCALLS);
             }
         }
     }

     /**
      * nextDouble(non-positive) throws IllegalArgumentException
      */
     public void testNextDoubleBoundNonPositive() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextDouble(-17.0d),
             () -> sr.nextDouble(0.0d),
             () -> sr.nextDouble(-Double.MIN_VALUE),
             () -> sr.nextDouble(Double.NEGATIVE_INFINITY),
             () -> sr.nextDouble(Double.NaN),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * nextDouble(! (least < bound)) throws IllegalArgumentException
      */
     public void testNextDoubleBadBounds() {
         SplittableRandom sr = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> sr.nextDouble(17.0d, 2.0d),
             () -> sr.nextDouble(-42.0d, -42.0d),
             () -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
             () -> sr.nextDouble(Double.NaN, 0.0d),
             () -> sr.nextDouble(0.0d, Double.NaN),
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     // TODO: Test infinite bounds!
     //() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
     //() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),

     /**
      * nextDouble(least, bound) returns least <= value < bound;
      * repeated calls produce at least two distinct results
      */
     public void testNextDoubleBounded2() {
         SplittableRandom sr = new SplittableRandom();
         for (double least = 0.0001; least < 1.0e20; least *= 8) {
             for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
                 double f = sr.nextDouble(least, bound);
                 assertTrue(least <= f && f < bound);
                 int i = 0;
                 double j;
                 while (i < NCALLS &&
                        (j = sr.nextDouble(least, bound)) == f) {
                     assertTrue(least <= j && j < bound);
                     ++i;
                 }
                 assertTrue(i < NCALLS);
             }
         }
     }

     /**
      * Invoking sized ints, long, doubles, with negative sizes throws
      * IllegalArgumentException
      */
     public void testBadStreamSize() {
         SplittableRandom r = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> { java.util.stream.IntStream x = r.ints(-1L); },
             () -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
             () -> { java.util.stream.LongStream x = r.longs(-1L); },
             () -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
             () -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
             () -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * Invoking bounded ints, long, doubles, with illegal bounds throws
      * IllegalArgumentException
      */
     public void testBadStreamBounds() {
         SplittableRandom r = new SplittableRandom();
         Runnable[] throwingActions = {
             () -> { java.util.stream.IntStream x = r.ints(2, 1); },
             () -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
             () -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
             () -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
             () -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
             () -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
         };
         assertThrows(IllegalArgumentException.class, throwingActions);
     }

     /**
      * A parallel sized stream of ints generates the given number of values
      */
     public void testIntsCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 0;
         for (int reps = 0; reps < REPS; ++reps) {
             counter.reset();
             r.ints(size).parallel().forEach(x -> counter.increment());
             assertEquals(size, counter.sum());
             size += 524959;
         }
     }

     /**
      * A parallel sized stream of longs generates the given number of values
      */
     public void testLongsCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 0;
         for (int reps = 0; reps < REPS; ++reps) {
             counter.reset();
             r.longs(size).parallel().forEach(x -> counter.increment());
             assertEquals(size, counter.sum());
             size += 524959;
         }
     }

     /**
      * A parallel sized stream of doubles generates the given number of values
      */
     public void testDoublesCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 0;
         for (int reps = 0; reps < REPS; ++reps) {
             counter.reset();
             r.doubles(size).parallel().forEach(x -> counter.increment());
             assertEquals(size, counter.sum());
             size += 524959;
         }
     }

     /**
      * Each of a parallel sized stream of bounded ints is within bounds
      */
     public void testBoundedInts() {
         AtomicInteger fails = new AtomicInteger(0);
         SplittableRandom r = new SplittableRandom();
         long size = 12345L;
         for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
             for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
                 final int lo = least, hi = bound;
                 r.ints(size, lo, hi).parallel().forEach(
                     x -> {
                         if (x < lo || x >= hi)
                             fails.getAndIncrement(); });
             }
         }
         assertEquals(0, fails.get());
     }

     /**
      * Each of a parallel sized stream of bounded longs is within bounds
      */
     public void testBoundedLongs() {
         AtomicInteger fails = new AtomicInteger(0);
         SplittableRandom r = new SplittableRandom();
         long size = 123L;
         for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
             for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
                 final long lo = least, hi = bound;
                 r.longs(size, lo, hi).parallel().forEach(
                     x -> {
                         if (x < lo || x >= hi)
                             fails.getAndIncrement(); });
             }
         }
         assertEquals(0, fails.get());
     }

     /**
      * Each of a parallel sized stream of bounded doubles is within bounds
      */
     public void testBoundedDoubles() {
         AtomicInteger fails = new AtomicInteger(0);
         SplittableRandom r = new SplittableRandom();
         long size = 456;
         for (double least = 0.00011; least < 1.0e20; least *= 9) {
             for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
                 final double lo = least, hi = bound;
                 r.doubles(size, lo, hi).parallel().forEach(
                     x -> {
                         if (x < lo || x >= hi)
                             fails.getAndIncrement(); });
             }
         }
         assertEquals(0, fails.get());
     }

     /**
      * A parallel unsized stream of ints generates at least 100 values
      */
     public void testUnsizedIntsCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.ints().limit(size).parallel().forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * A parallel unsized stream of longs generates at least 100 values
      */
     public void testUnsizedLongsCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.longs().limit(size).parallel().forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * A parallel unsized stream of doubles generates at least 100 values
      */
     public void testUnsizedDoublesCount() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.doubles().limit(size).parallel().forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * A sequential unsized stream of ints generates at least 100 values
      */
     public void testUnsizedIntsCountSeq() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.ints().limit(size).forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * A sequential unsized stream of longs generates at least 100 values
      */
     public void testUnsizedLongsCountSeq() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.longs().limit(size).forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * A sequential unsized stream of doubles generates at least 100 values
      */
     public void testUnsizedDoublesCountSeq() {
         LongAdder counter = new LongAdder();
         SplittableRandom r = new SplittableRandom();
         long size = 100;
         r.doubles().limit(size).forEach(x -> counter.increment());
         assertEquals(size, counter.sum());
     }

     /**
      * SplittableRandom should implement most of Random's public methods
      */
     public void testShouldImplementMostRandomMethods() throws Throwable {
         Predicate<Method> wasForgotten = method -> {
             String name = method.getName();
             // some methods deliberately not implemented
             if (name.equals("setSeed")) return false;
             if (name.equals("nextFloat")) return false;
             if (name.equals("nextGaussian")) return false;
             try {
                 SplittableRandom.class.getMethod(
                     method.getName(), method.getParameterTypes());
             } catch (ReflectiveOperationException ex) {
                 return true;
             }
             return false;
         };
         List<Method> forgotten =
             Arrays.stream(java.util.Random.class.getMethods())
             .filter(wasForgotten)
             .collect(Collectors.toList());
         if (!forgotten.isEmpty())
             throw new AssertionError("Please implement: " + forgotten);
     }

     /**
      * Repeated calls to nextBytes produce at least values of different signs for every byte
      */
     public void testNextBytes() {
         SplittableRandom sr = new SplittableRandom();
         int n = sr.nextInt(1, 20);
         byte[] bytes = new byte[n];
         outer:
         for (int i = 0; i < n; i++) {
             for (int tries = NCALLS; tries-->0; ) {
                 byte before = bytes[i];
                 sr.nextBytes(bytes);
                 byte after = bytes[i];
                 if (after * before < 0)
                     continue outer;
             }
             fail("not enough variation in random bytes");
         }
     }

     /**
      * Filling an empty array with random bytes succeeds without effect.
      */
     public void testNextBytes_emptyArray() {
         new SplittableRandom().nextBytes(new byte[0]);
     }

     public void testNextBytes_nullArray() {
         try {
             new SplittableRandom().nextBytes(null);
             shouldThrow();
         } catch (NullPointerException success) {}
     }

 }
	/*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* This file is available under and governed by the GNU General Public
	* License version 2 only, as published by the Free Software Foundation.
	* However, the following notice accompanied the original version of this
	* file:
	*
	* Written by Doug Lea with assistance from members of JCP JSR-166
	* Expert Group and released to the public domain, as explained at
	* http://creativecommons.org/publicdomain/zero/1.0/
	*/

	import java.util.Arrays;
	import java.util.List;
	import java.util.SplittableRandom;
	import java.util.concurrent.atomic.AtomicInteger;
	import java.util.concurrent.atomic.LongAdder;
	import java.lang.reflect.Method;
	import java.util.function.Predicate;
	import java.util.stream.Collectors;

	import junit.framework.Test;
	import junit.framework.TestSuite;

	public class SplittableRandomTest extends JSR166TestCase {

	public static void main(String[] args) {
	main(suite(), args);
	}
	public static Test suite() {
	return new TestSuite(SplittableRandomTest.class);
	}

	/*
	* Testing coverage notes:
	*
	* 1. Many of the test methods are adapted from ThreadLocalRandomTest.
	*
	* 2. These tests do not check for random number generator quality.
	* But we check for minimal API compliance by requiring that
	* repeated calls to nextX methods, up to NCALLS tries, produce at
	* least two distinct results. (In some possible universe, a
	* "correct" implementation might fail, but the odds are vastly
	* less than that of encountering a hardware failure while running
	* the test.) For bounded nextX methods, we sample various
	* intervals across multiples of primes. In other tests, we repeat
	* under REPS different values.
	*/

	// max numbers of calls to detect getting stuck on one value
	static final int NCALLS = 10000;

	// max sampled int bound
	static final int MAX_INT_BOUND = (1 << 26);

	// max sampled long bound
	static final long MAX_LONG_BOUND = (1L << 40);

	// Number of replications for other checks
	static final int REPS =
	Integer.getInteger("SplittableRandomTest.reps", 4);

	/**
	* Repeated calls to nextInt produce at least two distinct results
	*/
	public void testNextInt() {
	SplittableRandom sr = new SplittableRandom();
	int f = sr.nextInt();
	int i = 0;
	while (i < NCALLS && sr.nextInt() == f)
	++i;
	assertTrue(i < NCALLS);
	}

	/**
	* Repeated calls to nextLong produce at least two distinct results
	*/
	public void testNextLong() {
	SplittableRandom sr = new SplittableRandom();
	long f = sr.nextLong();
	int i = 0;
	while (i < NCALLS && sr.nextLong() == f)
	++i;
	assertTrue(i < NCALLS);
	}

	/**
	* Repeated calls to nextDouble produce at least two distinct results
	*/
	public void testNextDouble() {
	SplittableRandom sr = new SplittableRandom();
	double f = sr.nextDouble();
	int i = 0;
	while (i < NCALLS && sr.nextDouble() == f)
	++i;
	assertTrue(i < NCALLS);
	}

	/**
	* Two SplittableRandoms created with the same seed produce the
	* same values for nextLong.
	*/
	public void testSeedConstructor() {
	for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
	SplittableRandom sr1 = new SplittableRandom(seed);
	SplittableRandom sr2 = new SplittableRandom(seed);
	for (int i = 0; i < REPS; ++i)
	assertEquals(sr1.nextLong(), sr2.nextLong());
	}
	}

	/**
	* A SplittableRandom produced by split() of a default-constructed
	* SplittableRandom generates a different sequence
	*/
	public void testSplit1() {
	SplittableRandom sr = new SplittableRandom();
	for (int reps = 0; reps < REPS; ++reps) {
	SplittableRandom sc = sr.split();
	int i = 0;
	while (i < NCALLS && sr.nextLong() == sc.nextLong())
	++i;
	assertTrue(i < NCALLS);
	}
	}

	/**
	* A SplittableRandom produced by split() of a seeded-constructed
	* SplittableRandom generates a different sequence
	*/
	public void testSplit2() {
	SplittableRandom sr = new SplittableRandom(12345);
	for (int reps = 0; reps < REPS; ++reps) {
	SplittableRandom sc = sr.split();
	int i = 0;
	while (i < NCALLS && sr.nextLong() == sc.nextLong())
	++i;
	assertTrue(i < NCALLS);
	}
	}

	/**
	* nextInt(non-positive) throws IllegalArgumentException
	*/
	public void testNextIntBoundNonPositive() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextInt(-17),
	() -> sr.nextInt(0),
	() -> sr.nextInt(Integer.MIN_VALUE),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* nextInt(least >= bound) throws IllegalArgumentException
	*/
	public void testNextIntBadBounds() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextInt(17, 2),
	() -> sr.nextInt(-42, -42),
	() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* nextInt(bound) returns 0 <= value < bound;
	* repeated calls produce at least two distinct results
	*/
	public void testNextIntBounded() {
	SplittableRandom sr = new SplittableRandom();
	for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
	// sample bound space across prime number increments
	for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
	int f = sr.nextInt(bound);
	assertTrue(0 <= f && f < bound);
	int i = 0;
	int j;
	while (i < NCALLS &&
	(j = sr.nextInt(bound)) == f) {
	assertTrue(0 <= j && j < bound);
	++i;
	}
	assertTrue(i < NCALLS);
	}
	}

	/**
	* nextInt(least, bound) returns least <= value < bound;
	* repeated calls produce at least two distinct results
	*/
	public void testNextIntBounded2() {
	SplittableRandom sr = new SplittableRandom();
	for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
	int f = sr.nextInt(least, bound);
	assertTrue(least <= f && f < bound);
	int i = 0;
	int j;
	while (i < NCALLS &&
	(j = sr.nextInt(least, bound)) == f) {
	assertTrue(least <= j && j < bound);
	++i;
	}
	assertTrue(i < NCALLS);
	}
	}
	}

	/**
	* nextLong(non-positive) throws IllegalArgumentException
	*/
	public void testNextLongBoundNonPositive() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextLong(-17L),
	() -> sr.nextLong(0L),
	() -> sr.nextLong(Long.MIN_VALUE),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* nextLong(least >= bound) throws IllegalArgumentException
	*/
	public void testNextLongBadBounds() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextLong(17L, 2L),
	() -> sr.nextLong(-42L, -42L),
	() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* nextLong(bound) returns 0 <= value < bound;
	* repeated calls produce at least two distinct results
	*/
	public void testNextLongBounded() {
	SplittableRandom sr = new SplittableRandom();
	for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
	for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
	long f = sr.nextLong(bound);
	assertTrue(0 <= f && f < bound);
	int i = 0;
	long j;
	while (i < NCALLS &&
	(j = sr.nextLong(bound)) == f) {
	assertTrue(0 <= j && j < bound);
	++i;
	}
	assertTrue(i < NCALLS);
	}
	}

	/**
	* nextLong(least, bound) returns least <= value < bound;
	* repeated calls produce at least two distinct results
	*/
	public void testNextLongBounded2() {
	SplittableRandom sr = new SplittableRandom();
	for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
	long f = sr.nextLong(least, bound);
	assertTrue(least <= f && f < bound);
	int i = 0;
	long j;
	while (i < NCALLS &&
	(j = sr.nextLong(least, bound)) == f) {
	assertTrue(least <= j && j < bound);
	++i;
	}
	assertTrue(i < NCALLS);
	}
	}
	}

	/**
	* nextDouble(non-positive) throws IllegalArgumentException
	*/
	public void testNextDoubleBoundNonPositive() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextDouble(-17.0d),
	() -> sr.nextDouble(0.0d),
	() -> sr.nextDouble(-Double.MIN_VALUE),
	() -> sr.nextDouble(Double.NEGATIVE_INFINITY),
	() -> sr.nextDouble(Double.NaN),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* nextDouble(! (least < bound)) throws IllegalArgumentException
	*/
	public void testNextDoubleBadBounds() {
	SplittableRandom sr = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> sr.nextDouble(17.0d, 2.0d),
	() -> sr.nextDouble(-42.0d, -42.0d),
	() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
	() -> sr.nextDouble(Double.NaN, 0.0d),
	() -> sr.nextDouble(0.0d, Double.NaN),
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	// TODO: Test infinite bounds!
	//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
	//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),

	/**
	* nextDouble(least, bound) returns least <= value < bound;
	* repeated calls produce at least two distinct results
	*/
	public void testNextDoubleBounded2() {
	SplittableRandom sr = new SplittableRandom();
	for (double least = 0.0001; least < 1.0e20; least *= 8) {
	for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
	double f = sr.nextDouble(least, bound);
	assertTrue(least <= f && f < bound);
	int i = 0;
	double j;
	while (i < NCALLS &&
	(j = sr.nextDouble(least, bound)) == f) {
	assertTrue(least <= j && j < bound);
	++i;
	}
	assertTrue(i < NCALLS);
	}
	}
	}

	/**
	* Invoking sized ints, long, doubles, with negative sizes throws
	* IllegalArgumentException
	*/
	public void testBadStreamSize() {
	SplittableRandom r = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> { java.util.stream.IntStream x = r.ints(-1L); },
	() -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
	() -> { java.util.stream.LongStream x = r.longs(-1L); },
	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
	() -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
	() -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* Invoking bounded ints, long, doubles, with illegal bounds throws
	* IllegalArgumentException
	*/
	public void testBadStreamBounds() {
	SplittableRandom r = new SplittableRandom();
	Runnable[] throwingActions = {
	() -> { java.util.stream.IntStream x = r.ints(2, 1); },
	() -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
	() -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
	() -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
	() -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
	};
	assertThrows(IllegalArgumentException.class, throwingActions);
	}

	/**
	* A parallel sized stream of ints generates the given number of values
	*/
	public void testIntsCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 0;
	for (int reps = 0; reps < REPS; ++reps) {
	counter.reset();
	r.ints(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	size += 524959;
	}
	}

	/**
	* A parallel sized stream of longs generates the given number of values
	*/
	public void testLongsCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 0;
	for (int reps = 0; reps < REPS; ++reps) {
	counter.reset();
	r.longs(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	size += 524959;
	}
	}

	/**
	* A parallel sized stream of doubles generates the given number of values
	*/
	public void testDoublesCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 0;
	for (int reps = 0; reps < REPS; ++reps) {
	counter.reset();
	r.doubles(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	size += 524959;
	}
	}

	/**
	* Each of a parallel sized stream of bounded ints is within bounds
	*/
	public void testBoundedInts() {
	AtomicInteger fails = new AtomicInteger(0);
	SplittableRandom r = new SplittableRandom();
	long size = 12345L;
	for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
	final int lo = least, hi = bound;
	r.ints(size, lo, hi).parallel().forEach(
	x -> {
	if (x < lo \|\| x >= hi)
	fails.getAndIncrement(); });
	}
	}
	assertEquals(0, fails.get());
	}

	/**
	* Each of a parallel sized stream of bounded longs is within bounds
	*/
	public void testBoundedLongs() {
	AtomicInteger fails = new AtomicInteger(0);
	SplittableRandom r = new SplittableRandom();
	long size = 123L;
	for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
	final long lo = least, hi = bound;
	r.longs(size, lo, hi).parallel().forEach(
	x -> {
	if (x < lo \|\| x >= hi)
	fails.getAndIncrement(); });
	}
	}
	assertEquals(0, fails.get());
	}

	/**
	* Each of a parallel sized stream of bounded doubles is within bounds
	*/
	public void testBoundedDoubles() {
	AtomicInteger fails = new AtomicInteger(0);
	SplittableRandom r = new SplittableRandom();
	long size = 456;
	for (double least = 0.00011; least < 1.0e20; least *= 9) {
	for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
	final double lo = least, hi = bound;
	r.doubles(size, lo, hi).parallel().forEach(
	x -> {
	if (x < lo \|\| x >= hi)
	fails.getAndIncrement(); });
	}
	}
	assertEquals(0, fails.get());
	}

	/**
	* A parallel unsized stream of ints generates at least 100 values
	*/
	public void testUnsizedIntsCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.ints().limit(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* A parallel unsized stream of longs generates at least 100 values
	*/
	public void testUnsizedLongsCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.longs().limit(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* A parallel unsized stream of doubles generates at least 100 values
	*/
	public void testUnsizedDoublesCount() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.doubles().limit(size).parallel().forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* A sequential unsized stream of ints generates at least 100 values
	*/
	public void testUnsizedIntsCountSeq() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.ints().limit(size).forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* A sequential unsized stream of longs generates at least 100 values
	*/
	public void testUnsizedLongsCountSeq() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.longs().limit(size).forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* A sequential unsized stream of doubles generates at least 100 values
	*/
	public void testUnsizedDoublesCountSeq() {
	LongAdder counter = new LongAdder();
	SplittableRandom r = new SplittableRandom();
	long size = 100;
	r.doubles().limit(size).forEach(x -> counter.increment());
	assertEquals(size, counter.sum());
	}

	/**
	* SplittableRandom should implement most of Random's public methods
	*/
	public void testShouldImplementMostRandomMethods() throws Throwable {
	Predicate<Method> wasForgotten = method -> {
	String name = method.getName();
	// some methods deliberately not implemented
	if (name.equals("setSeed")) return false;
	if (name.equals("nextFloat")) return false;
	if (name.equals("nextGaussian")) return false;
	try {
	SplittableRandom.class.getMethod(
	method.getName(), method.getParameterTypes());
	} catch (ReflectiveOperationException ex) {
	return true;
	}
	return false;
	};
	List<Method> forgotten =
	Arrays.stream(java.util.Random.class.getMethods())
	.filter(wasForgotten)
	.collect(Collectors.toList());
	if (!forgotten.isEmpty())
	throw new AssertionError("Please implement: " + forgotten);
	}

	/**
	* Repeated calls to nextBytes produce at least values of different signs for every byte
	*/
	public void testNextBytes() {
	SplittableRandom sr = new SplittableRandom();
	int n = sr.nextInt(1, 20);
	byte[] bytes = new byte[n];
	outer:
	for (int i = 0; i < n; i++) {
	for (int tries = NCALLS; tries-->0; ) {
	byte before = bytes[i];
	sr.nextBytes(bytes);
	byte after = bytes[i];
	if (after * before < 0)
	continue outer;
	}
	fail("not enough variation in random bytes");
	}
	}

	/**
	* Filling an empty array with random bytes succeeds without effect.
	*/
	public void testNextBytes_emptyArray() {
	new SplittableRandom().nextBytes(new byte[0]);
	}

	public void testNextBytes_nullArray() {
	try {
	new SplittableRandom().nextBytes(null);
	shouldThrow();
	} catch (NullPointerException success) {}
	}

	}