1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.

     7  *

     8  * This code is distributed in the hope that it will be useful, but WITHOUT

     9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    11  * version 2 for more details (a copy is included in the LICENSE file that

    12  * accompanied this code).

    13  *

    14  * You should have received a copy of the GNU General Public License version

    15  * 2 along with this work; if not, write to the Free Software Foundation,

    16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    17  *

    18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    19  * or visit www.oracle.com if you need additional information or have any

    20  * questions.

    21  */

    22 

    23 /*

    24  * This file is available under and governed by the GNU General Public

    25  * License version 2 only, as published by the Free Software Foundation.

    26  * However, the following notice accompanied the original version of this

    27  * file:

    28  *

    29  * Written by Doug Lea with assistance from members of JCP JSR-166

    30  * Expert Group and released to the public domain, as explained at

    31  * http://creativecommons.org/publicdomain/zero/1.0/

    32  */

    33 

    34 import java.util.SplittableRandom;

    35 import java.util.concurrent.atomic.AtomicInteger;

    36 import java.util.concurrent.atomic.LongAdder;

    37 

    38 import junit.framework.Test;

    39 import junit.framework.TestSuite;

    40 

    41 public class SplittableRandomTest extends JSR166TestCase {

    42 

    43     public static void main(String[] args) {

    44         main(suite(), args);

    45     }

    46     public static Test suite() {

    47         return new TestSuite(SplittableRandomTest.class);

    48     }

    49 

    50     /*

    51      * Testing coverage notes:

    52      *

    53      * 1. Many of the test methods are adapted from ThreadLocalRandomTest.

    54      *

    55      * 2. These tests do not check for random number generator quality.

    56      * But we check for minimal API compliance by requiring that

    57      * repeated calls to nextX methods, up to NCALLS tries, produce at

    58      * least two distinct results. (In some possible universe, a

    59      * "correct" implementation might fail, but the odds are vastly

    60      * less than that of encountering a hardware failure while running

    61      * the test.) For bounded nextX methods, we sample various

    62      * intervals across multiples of primes. In other tests, we repeat

    63      * under REPS different values.

    64      */

    65 

    66     // max numbers of calls to detect getting stuck on one value

    67     static final int NCALLS = 10000;

    68 

    69     // max sampled int bound

    70     static final int MAX_INT_BOUND = (1 << 26);

    71 

    72     // max sampled long bound

    73     static final long MAX_LONG_BOUND = (1L << 40);

    74 

    75     // Number of replications for other checks

    76     static final int REPS =

    77         Integer.getInteger("SplittableRandomTest.reps", 4);

    78 

    79     /**

    80      * Repeated calls to nextInt produce at least two distinct results

    81      */

    82     public void testNextInt() {

    83         SplittableRandom sr = new SplittableRandom();

    84         int f = sr.nextInt();

    85         int i = 0;

    86         while (i < NCALLS && sr.nextInt() == f)

    87             ++i;

    88         assertTrue(i < NCALLS);

    89     }

    90 

    91     /**

    92      * Repeated calls to nextLong produce at least two distinct results

    93      */

    94     public void testNextLong() {

    95         SplittableRandom sr = new SplittableRandom();

    96         long f = sr.nextLong();

    97         int i = 0;

    98         while (i < NCALLS && sr.nextLong() == f)

    99             ++i;

   100         assertTrue(i < NCALLS);

   101     }

   102 

   103     /**

   104      * Repeated calls to nextDouble produce at least two distinct results

   105      */

   106     public void testNextDouble() {

   107         SplittableRandom sr = new SplittableRandom();

   108         double f = sr.nextDouble();

   109         int i = 0;

   110         while (i < NCALLS && sr.nextDouble() == f)

   111             ++i;

   112         assertTrue(i < NCALLS);

   113     }

   114 

   115     /**

   116      * Two SplittableRandoms created with the same seed produce the

   117      * same values for nextLong.

   118      */

   119     public void testSeedConstructor() {

   120         for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {

   121             SplittableRandom sr1 = new SplittableRandom(seed);

   122             SplittableRandom sr2 = new SplittableRandom(seed);

   123             for (int i = 0; i < REPS; ++i)

   124                 assertEquals(sr1.nextLong(), sr2.nextLong());

   125         }

   126     }

   127 

   128     /**

   129      * A SplittableRandom produced by split() of a default-constructed

   130      * SplittableRandom generates a different sequence

   131      */

   132     public void testSplit1() {

   133         SplittableRandom sr = new SplittableRandom();

   134         for (int reps = 0; reps < REPS; ++reps) {

   135             SplittableRandom sc = sr.split();

   136             int i = 0;

   137             while (i < NCALLS && sr.nextLong() == sc.nextLong())

   138                 ++i;

   139             assertTrue(i < NCALLS);

   140         }

   141     }

   142 

   143     /**

   144      * A SplittableRandom produced by split() of a seeded-constructed

   145      * SplittableRandom generates a different sequence

   146      */

   147     public void testSplit2() {

   148         SplittableRandom sr = new SplittableRandom(12345);

   149         for (int reps = 0; reps < REPS; ++reps) {

   150             SplittableRandom sc = sr.split();

   151             int i = 0;

   152             while (i < NCALLS && sr.nextLong() == sc.nextLong())

   153                 ++i;

   154             assertTrue(i < NCALLS);

   155         }

   156     }

   157 

   158     /**

   159      * nextInt(non-positive) throws IllegalArgumentException

   160      */

   161     public void testNextIntBoundNonPositive() {

   162         SplittableRandom sr = new SplittableRandom();

   163         Runnable[] throwingActions = {

   164             () -> sr.nextInt(-17),

   165             () -> sr.nextInt(0),

   166             () -> sr.nextInt(Integer.MIN_VALUE),

   167         };

   168         assertThrows(IllegalArgumentException.class, throwingActions);

   169     }

   170 

   171     /**

   172      * nextInt(least >= bound) throws IllegalArgumentException

   173      */

   174     public void testNextIntBadBounds() {

   175         SplittableRandom sr = new SplittableRandom();

   176         Runnable[] throwingActions = {

   177             () -> sr.nextInt(17, 2),

   178             () -> sr.nextInt(-42, -42),

   179             () -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),

   180         };

   181         assertThrows(IllegalArgumentException.class, throwingActions);

   182     }

   183 

   184     /**

   185      * nextInt(bound) returns 0 <= value < bound;

   186      * repeated calls produce at least two distinct results

   187      */

   188     public void testNextIntBounded() {

   189         SplittableRandom sr = new SplittableRandom();

   190         for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));

   191         // sample bound space across prime number increments

   192         for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {

   193             int f = sr.nextInt(bound);

   194             assertTrue(0 <= f && f < bound);

   195             int i = 0;

   196             int j;

   197             while (i < NCALLS &&

   198                    (j = sr.nextInt(bound)) == f) {

   199                 assertTrue(0 <= j && j < bound);

   200                 ++i;

   201             }

   202             assertTrue(i < NCALLS);

   203         }

   204     }

   205 

   206     /**

   207      * nextInt(least, bound) returns least <= value < bound;

   208      * repeated calls produce at least two distinct results

   209      */

   210     public void testNextIntBounded2() {

   211         SplittableRandom sr = new SplittableRandom();

   212         for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {

   213             for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {

   214                 int f = sr.nextInt(least, bound);

   215                 assertTrue(least <= f && f < bound);

   216                 int i = 0;

   217                 int j;

   218                 while (i < NCALLS &&

   219                        (j = sr.nextInt(least, bound)) == f) {

   220                     assertTrue(least <= j && j < bound);

   221                     ++i;

   222                 }

   223                 assertTrue(i < NCALLS);

   224             }

   225         }

   226     }

   227 

   228     /**

   229      * nextLong(non-positive) throws IllegalArgumentException

   230      */

   231     public void testNextLongBoundNonPositive() {

   232         SplittableRandom sr = new SplittableRandom();

   233         Runnable[] throwingActions = {

   234             () -> sr.nextLong(-17L),

   235             () -> sr.nextLong(0L),

   236             () -> sr.nextLong(Long.MIN_VALUE),

   237         };

   238         assertThrows(IllegalArgumentException.class, throwingActions);

   239     }

   240 

   241     /**

   242      * nextLong(least >= bound) throws IllegalArgumentException

   243      */

   244     public void testNextLongBadBounds() {

   245         SplittableRandom sr = new SplittableRandom();

   246         Runnable[] throwingActions = {

   247             () -> sr.nextLong(17L, 2L),

   248             () -> sr.nextLong(-42L, -42L),

   249             () -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),

   250         };

   251         assertThrows(IllegalArgumentException.class, throwingActions);

   252     }

   253 

   254     /**

   255      * nextLong(bound) returns 0 <= value < bound;

   256      * repeated calls produce at least two distinct results

   257      */

   258     public void testNextLongBounded() {

   259         SplittableRandom sr = new SplittableRandom();

   260         for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));

   261         for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {

   262             long f = sr.nextLong(bound);

   263             assertTrue(0 <= f && f < bound);

   264             int i = 0;

   265             long j;

   266             while (i < NCALLS &&

   267                    (j = sr.nextLong(bound)) == f) {

   268                 assertTrue(0 <= j && j < bound);

   269                 ++i;

   270             }

   271             assertTrue(i < NCALLS);

   272         }

   273     }

   274 

   275     /**

   276      * nextLong(least, bound) returns least <= value < bound;

   277      * repeated calls produce at least two distinct results

   278      */

   279     public void testNextLongBounded2() {

   280         SplittableRandom sr = new SplittableRandom();

   281         for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {

   282             for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {

   283                 long f = sr.nextLong(least, bound);

   284                 assertTrue(least <= f && f < bound);

   285                 int i = 0;

   286                 long j;

   287                 while (i < NCALLS &&

   288                        (j = sr.nextLong(least, bound)) == f) {

   289                     assertTrue(least <= j && j < bound);

   290                     ++i;

   291                 }

   292                 assertTrue(i < NCALLS);

   293             }

   294         }

   295     }

   296 

   297     /**

   298      * nextDouble(non-positive) throws IllegalArgumentException

   299      */

   300     public void testNextDoubleBoundNonPositive() {

   301         SplittableRandom sr = new SplittableRandom();

   302         Runnable[] throwingActions = {

   303             () -> sr.nextDouble(-17.0d),

   304             () -> sr.nextDouble(0.0d),

   305             () -> sr.nextDouble(-Double.MIN_VALUE),

   306             () -> sr.nextDouble(Double.NEGATIVE_INFINITY),

   307             () -> sr.nextDouble(Double.NaN),

   308         };

   309         assertThrows(IllegalArgumentException.class, throwingActions);

   310     }

   311 

   312     /**

   313      * nextDouble(! (least < bound)) throws IllegalArgumentException

   314      */

   315     public void testNextDoubleBadBounds() {

   316         SplittableRandom sr = new SplittableRandom();

   317         Runnable[] throwingActions = {

   318             () -> sr.nextDouble(17.0d, 2.0d),

   319             () -> sr.nextDouble(-42.0d, -42.0d),

   320             () -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),

   321             () -> sr.nextDouble(Double.NaN, 0.0d),

   322             () -> sr.nextDouble(0.0d, Double.NaN),

   323         };

   324         assertThrows(IllegalArgumentException.class, throwingActions);

   325     }

   326 

   327     // TODO: Test infinite bounds!

   328     //() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),

   329     //() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),

   330 

   331     /**

   332      * nextDouble(least, bound) returns least <= value < bound;

   333      * repeated calls produce at least two distinct results

   334      */

   335     public void testNextDoubleBounded2() {

   336         SplittableRandom sr = new SplittableRandom();

   337         for (double least = 0.0001; least < 1.0e20; least *= 8) {

   338             for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {

   339                 double f = sr.nextDouble(least, bound);

   340                 assertTrue(least <= f && f < bound);

   341                 int i = 0;

   342                 double j;

   343                 while (i < NCALLS &&

   344                        (j = sr.nextDouble(least, bound)) == f) {

   345                     assertTrue(least <= j && j < bound);

   346                     ++i;

   347                 }

   348                 assertTrue(i < NCALLS);

   349             }

   350         }

   351     }

   352 

   353     /**

   354      * Invoking sized ints, long, doubles, with negative sizes throws

   355      * IllegalArgumentException

   356      */

   357     public void testBadStreamSize() {

   358         SplittableRandom r = new SplittableRandom();

   359         Runnable[] throwingActions = {

   360             () -> { java.util.stream.IntStream x = r.ints(-1L); },

   361             () -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },

   362             () -> { java.util.stream.LongStream x = r.longs(-1L); },

   363             () -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },

   364             () -> { java.util.stream.DoubleStream x = r.doubles(-1L); },

   365             () -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },

   366         };

   367         assertThrows(IllegalArgumentException.class, throwingActions);

   368     }

   369 

   370     /**

   371      * Invoking bounded ints, long, doubles, with illegal bounds throws

   372      * IllegalArgumentException

   373      */

   374     public void testBadStreamBounds() {

   375         SplittableRandom r = new SplittableRandom();

   376         Runnable[] throwingActions = {

   377             () -> { java.util.stream.IntStream x = r.ints(2, 1); },

   378             () -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },

   379             () -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },

   380             () -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },

   381             () -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },

   382             () -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },

   383         };

   384         assertThrows(IllegalArgumentException.class, throwingActions);

   385     }

   386 

   387     /**

   388      * A parallel sized stream of ints generates the given number of values

   389      */

   390     public void testIntsCount() {

   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.ints(size).parallel().forEach(x -> counter.increment());

   397             assertEquals(size, counter.sum());

   398             size += 524959;

   399         }

   400     }

   401 

   402     /**

   403      * A parallel sized stream of longs generates the given number of values

   404      */

   405     public void testLongsCount() {

   406         LongAdder counter = new LongAdder();

   407         SplittableRandom r = new SplittableRandom();

   408         long size = 0;

   409         for (int reps = 0; reps < REPS; ++reps) {

   410             counter.reset();

   411             r.longs(size).parallel().forEach(x -> counter.increment());

   412             assertEquals(size, counter.sum());

   413             size += 524959;

   414         }

   415     }

   416 

   417     /**

   418      * A parallel sized stream of doubles generates the given number of values

   419      */

   420     public void testDoublesCount() {

   421         LongAdder counter = new LongAdder();

   422         SplittableRandom r = new SplittableRandom();

   423         long size = 0;

   424         for (int reps = 0; reps < REPS; ++reps) {

   425             counter.reset();

   426             r.doubles(size).parallel().forEach(x -> counter.increment());

   427             assertEquals(size, counter.sum());

   428             size += 524959;

   429         }

   430     }

   431 

   432     /**

   433      * Each of a parallel sized stream of bounded ints is within bounds

   434      */

   435     public void testBoundedInts() {

   436         AtomicInteger fails = new AtomicInteger(0);

   437         SplittableRandom r = new SplittableRandom();

   438         long size = 12345L;

   439         for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {

   440             for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {

   441                 final int lo = least, hi = bound;

   442                 r.ints(size, lo, hi).parallel().forEach(

   443                     x -> {

   444                         if (x < lo || x >= hi)

   445                             fails.getAndIncrement(); });

   446             }

   447         }

   448         assertEquals(0, fails.get());

   449     }

   450 

   451     /**

   452      * Each of a parallel sized stream of bounded longs is within bounds

   453      */

   454     public void testBoundedLongs() {

   455         AtomicInteger fails = new AtomicInteger(0);

   456         SplittableRandom r = new SplittableRandom();

   457         long size = 123L;

   458         for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {

   459             for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {

   460                 final long lo = least, hi = bound;

   461                 r.longs(size, lo, hi).parallel().forEach(

   462                     x -> {

   463                         if (x < lo || x >= hi)

   464                             fails.getAndIncrement(); });

   465             }

   466         }

   467         assertEquals(0, fails.get());

   468     }

   469 

   470     /**

   471      * Each of a parallel sized stream of bounded doubles is within bounds

   472      */

   473     public void testBoundedDoubles() {

   474         AtomicInteger fails = new AtomicInteger(0);

   475         SplittableRandom r = new SplittableRandom();

   476         long size = 456;

   477         for (double least = 0.00011; least < 1.0e20; least *= 9) {

   478             for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {

   479                 final double lo = least, hi = bound;

   480                 r.doubles(size, lo, hi).parallel().forEach(

   481                     x -> {

   482                         if (x < lo || x >= hi)

   483                             fails.getAndIncrement(); });

   484             }

   485         }

   486         assertEquals(0, fails.get());

   487     }

   488 

   489     /**

   490      * A parallel unsized stream of ints generates at least 100 values

   491      */

   492     public void testUnsizedIntsCount() {

   493         LongAdder counter = new LongAdder();

   494         SplittableRandom r = new SplittableRandom();

   495         long size = 100;

   496         r.ints().limit(size).parallel().forEach(x -> counter.increment());

   497         assertEquals(size, counter.sum());

   498     }

   499 

   500     /**

   501      * A parallel unsized stream of longs generates at least 100 values

   502      */

   503     public void testUnsizedLongsCount() {

   504         LongAdder counter = new LongAdder();

   505         SplittableRandom r = new SplittableRandom();

   506         long size = 100;

   507         r.longs().limit(size).parallel().forEach(x -> counter.increment());

   508         assertEquals(size, counter.sum());

   509     }

   510 

   511     /**

   512      * A parallel unsized stream of doubles generates at least 100 values

   513      */

   514     public void testUnsizedDoublesCount() {

   515         LongAdder counter = new LongAdder();

   516         SplittableRandom r = new SplittableRandom();

   517         long size = 100;

   518         r.doubles().limit(size).parallel().forEach(x -> counter.increment());

   519         assertEquals(size, counter.sum());

   520     }

   521 

   522     /**

   523      * A sequential unsized stream of ints generates at least 100 values

   524      */

   525     public void testUnsizedIntsCountSeq() {

   526         LongAdder counter = new LongAdder();

   527         SplittableRandom r = new SplittableRandom();

   528         long size = 100;

   529         r.ints().limit(size).forEach(x -> counter.increment());

   530         assertEquals(size, counter.sum());

   531     }

   532 

   533     /**

   534      * A sequential unsized stream of longs generates at least 100 values

   535      */

   536     public void testUnsizedLongsCountSeq() {

   537         LongAdder counter = new LongAdder();

   538         SplittableRandom r = new SplittableRandom();

   539         long size = 100;

   540         r.longs().limit(size).forEach(x -> counter.increment());

   541         assertEquals(size, counter.sum());

   542     }

   543 

   544     /**

   545      * A sequential unsized stream of doubles generates at least 100 values

   546      */

   547     public void testUnsizedDoublesCountSeq() {

   548         LongAdder counter = new LongAdder();

   549         SplittableRandom r = new SplittableRandom();

   550         long size = 100;

   551         r.doubles().limit(size).forEach(x -> counter.increment());

   552         assertEquals(size, counter.sum());

   553     }

   554 

   555 }