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Comparing jsr166/src/test/tck/SplittableRandomTest.java (file contents):
Revision 1.1 by dl, Thu Jul 11 19:08:12 2013 UTC vs.
Revision 1.26 by jsr166, Mon Dec 16 22:55:54 2019 UTC

# Line 3 | Line 3
3   * Expert Group and released to the public domain, as explained at
4   * http://creativecommons.org/publicdomain/zero/1.0/
5   */
6 < import junit.framework.*;
7 < import java.util.*;
6 >
7 > import java.util.Arrays;
8 > import java.util.List;
9   import java.util.SplittableRandom;
10   import java.util.concurrent.atomic.AtomicInteger;
10 import java.util.concurrent.atomic.AtomicLong;
11   import java.util.concurrent.atomic.LongAdder;
12 + import java.lang.reflect.Method;
13 + import java.util.function.Predicate;
14 + import java.util.stream.Collectors;
15 + import java.util.stream.DoubleStream;
16 + import java.util.stream.IntStream;
17 + import java.util.stream.LongStream;
18 +
19 + import junit.framework.Test;
20 + import junit.framework.TestSuite;
21  
22   public class SplittableRandomTest extends JSR166TestCase {
23  
24      public static void main(String[] args) {
25 <        junit.textui.TestRunner.run(suite());
25 >        main(suite(), args);
26      }
27      public static Test suite() {
28          return new TestSuite(SplittableRandomTest.class);
# Line 22 | Line 31 | public class SplittableRandomTest extend
31      /*
32       * Testing coverage notes:
33       *
34 <     * 1. Many of the test methods are adapted from ThreadLocalRandomTest
34 >     * 1. Many of the test methods are adapted from ThreadLocalRandomTest.
35       *
36 <     * 2. This set of tests do not check for random number generator
37 <     * quality. But we check for minimal API compliance by requiring
38 <     * that repeated calls to nextX methods, up to NCALLS tries,
39 <     * produce at least one different result. (In some possible
40 <     * universe, a "correct" implementation might fail, but the odds
41 <     * are vastly less than that of encountering a hardware failure
42 <     * while running the test.) For bounded nextX methods, we sample
43 <     * various intervals across multiples of primes. In other tests,
44 <     * we repeat under REPS different values.
36 >     * 2. These tests do not check for random number generator quality.
37 >     * But we check for minimal API compliance by requiring that
38 >     * repeated calls to nextX methods, up to NCALLS tries, produce at
39 >     * least two distinct results. (In some possible universe, a
40 >     * "correct" implementation might fail, but the odds are vastly
41 >     * less than that of encountering a hardware failure while running
42 >     * the test.) For bounded nextX methods, we sample various
43 >     * intervals across multiples of primes. In other tests, we repeat
44 >     * under REPS different values.
45       */
46  
47      // max numbers of calls to detect getting stuck on one value
48      static final int NCALLS = 10000;
49  
50      // max sampled int bound
51 <    static final int MAX_INT_BOUND = (1 << 28);
51 >    static final int MAX_INT_BOUND = (1 << 26);
52  
53 <    // Max sampled long bound
54 <    static final long MAX_LONG_BOUND = (1L << 42);
53 >    // max sampled long bound
54 >    static final long MAX_LONG_BOUND = (1L << 40);
55  
56      // Number of replications for other checks
57 <    static final int REPS = 20;
57 >    static final int REPS =
58 >        Integer.getInteger("SplittableRandomTest.reps", 4);
59  
60      /**
61 <     * Repeated calls to nextInt produce at least one different result
61 >     * Repeated calls to nextInt produce at least two distinct results
62       */
63      public void testNextInt() {
64          SplittableRandom sr = new SplittableRandom();
# Line 60 | Line 70 | public class SplittableRandomTest extend
70      }
71  
72      /**
73 <     * Repeated calls to nextLong produce at least one different result
73 >     * Repeated calls to nextLong produce at least two distinct results
74       */
75      public void testNextLong() {
76          SplittableRandom sr = new SplittableRandom();
# Line 72 | Line 82 | public class SplittableRandomTest extend
82      }
83  
84      /**
85 <     * Repeated calls to nextDouble produce at least one different result
85 >     * Repeated calls to nextDouble produce at least two distinct results
86       */
87      public void testNextDouble() {
88          SplittableRandom sr = new SplittableRandom();
89          double f = sr.nextDouble();
90 <        double i = 0;
90 >        int i = 0;
91          while (i < NCALLS && sr.nextDouble() == f)
92              ++i;
93          assertTrue(i < NCALLS);
# Line 88 | Line 98 | public class SplittableRandomTest extend
98       * same values for nextLong.
99       */
100      public void testSeedConstructor() {
101 <        for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863)  {
101 >        for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
102              SplittableRandom sr1 = new SplittableRandom(seed);
103              SplittableRandom sr2 = new SplittableRandom(seed);
104 <            for (int i = 0; i < REPS; ++i)
104 >            for (int i = 0; i < REPS; ++i)
105                  assertEquals(sr1.nextLong(), sr2.nextLong());
106          }
107      }
# Line 127 | Line 137 | public class SplittableRandomTest extend
137      }
138  
139      /**
140 <     * nextInt(negative) throws IllegalArgumentException;
140 >     * nextInt(non-positive) throws IllegalArgumentException
141       */
142 <    public void testNextIntBoundedNeg() {
142 >    public void testNextIntBoundNonPositive() {
143          SplittableRandom sr = new SplittableRandom();
144 <        try {
145 <            int f = sr.nextInt(-17);
146 <            shouldThrow();
147 <        } catch (IllegalArgumentException success) {}
144 >        assertThrows(
145 >            IllegalArgumentException.class,
146 >            () -> sr.nextInt(-17),
147 >            () -> sr.nextInt(0),
148 >            () -> sr.nextInt(Integer.MIN_VALUE));
149      }
150  
151      /**
152 <     * nextInt(least >= bound) throws IllegalArgumentException;
152 >     * nextInt(least >= bound) throws IllegalArgumentException
153       */
154      public void testNextIntBadBounds() {
155          SplittableRandom sr = new SplittableRandom();
156 <        try {
157 <            int f = sr.nextInt(17, 2);
158 <            shouldThrow();
159 <        } catch (IllegalArgumentException success) {}
156 >        assertThrows(
157 >            IllegalArgumentException.class,
158 >            () -> sr.nextInt(17, 2),
159 >            () -> sr.nextInt(-42, -42),
160 >            () -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE));
161      }
162  
163      /**
164       * nextInt(bound) returns 0 <= value < bound;
165 <     * repeated calls produce at least one different result
165 >     * repeated calls produce at least two distinct results
166       */
167      public void testNextIntBounded() {
168          SplittableRandom sr = new SplittableRandom();
169 +        for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
170          // sample bound space across prime number increments
171          for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
172              int f = sr.nextInt(bound);
# Line 171 | Line 184 | public class SplittableRandomTest extend
184  
185      /**
186       * nextInt(least, bound) returns least <= value < bound;
187 <     * repeated calls produce at least one different result
187 >     * repeated calls produce at least two distinct results
188       */
189      public void testNextIntBounded2() {
190          SplittableRandom sr = new SplittableRandom();
# Line 192 | Line 205 | public class SplittableRandomTest extend
205      }
206  
207      /**
208 <     * nextLong(negative) throws IllegalArgumentException;
208 >     * nextLong(non-positive) throws IllegalArgumentException
209       */
210 <    public void testNextLongBoundedNeg() {
210 >    public void testNextLongBoundNonPositive() {
211          SplittableRandom sr = new SplittableRandom();
212 <        try {
213 <            long f = sr.nextLong(-17);
214 <            shouldThrow();
215 <        } catch (IllegalArgumentException success) {}
212 >        assertThrows(
213 >            IllegalArgumentException.class,
214 >            () -> sr.nextLong(-17L),
215 >            () -> sr.nextLong(0L),
216 >            () -> sr.nextLong(Long.MIN_VALUE));
217      }
218  
219      /**
220 <     * nextLong(least >= bound) throws IllegalArgumentException;
220 >     * nextLong(least >= bound) throws IllegalArgumentException
221       */
222      public void testNextLongBadBounds() {
223          SplittableRandom sr = new SplittableRandom();
224 <        try {
225 <            long f = sr.nextLong(17, 2);
226 <            shouldThrow();
227 <        } catch (IllegalArgumentException success) {}
224 >        assertThrows(
225 >            IllegalArgumentException.class,
226 >            () -> sr.nextLong(17L, 2L),
227 >            () -> sr.nextLong(-42L, -42L),
228 >            () -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE));
229      }
230  
231      /**
232       * nextLong(bound) returns 0 <= value < bound;
233 <     * repeated calls produce at least one different result
233 >     * repeated calls produce at least two distinct results
234       */
235      public void testNextLongBounded() {
236          SplittableRandom sr = new SplittableRandom();
237 +        for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
238          for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
239              long f = sr.nextLong(bound);
240              assertTrue(0 <= f && f < bound);
# Line 235 | Line 251 | public class SplittableRandomTest extend
251  
252      /**
253       * nextLong(least, bound) returns least <= value < bound;
254 <     * repeated calls produce at least one different result
254 >     * repeated calls produce at least two distinct results
255       */
256      public void testNextLongBounded2() {
257          SplittableRandom sr = new SplittableRandom();
# Line 256 | Line 272 | public class SplittableRandomTest extend
272      }
273  
274      /**
275 +     * nextDouble(non-positive) throws IllegalArgumentException
276 +     */
277 +    public void testNextDoubleBoundNonPositive() {
278 +        SplittableRandom sr = new SplittableRandom();
279 +        assertThrows(
280 +            IllegalArgumentException.class,
281 +            () -> sr.nextDouble(-17.0d),
282 +            () -> sr.nextDouble(0.0d),
283 +            () -> sr.nextDouble(-Double.MIN_VALUE),
284 +            () -> sr.nextDouble(Double.NEGATIVE_INFINITY),
285 +            () -> sr.nextDouble(Double.NaN));
286 +    }
287 +
288 +    /**
289 +     * nextDouble(! (least < bound)) throws IllegalArgumentException
290 +     */
291 +    public void testNextDoubleBadBounds() {
292 +        SplittableRandom sr = new SplittableRandom();
293 +        assertThrows(
294 +            IllegalArgumentException.class,
295 +            () -> sr.nextDouble(17.0d, 2.0d),
296 +            () -> sr.nextDouble(-42.0d, -42.0d),
297 +            () -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
298 +            () -> sr.nextDouble(Double.NaN, 0.0d),
299 +            () -> sr.nextDouble(0.0d, Double.NaN));
300 +    }
301 +
302 +    // TODO: Test infinite bounds!
303 +    //() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
304 +    //() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),
305 +
306 +    /**
307       * nextDouble(least, bound) returns least <= value < bound;
308 <     * repeated calls produce at least one different result
308 >     * repeated calls produce at least two distinct results
309       */
310      public void testNextDoubleBounded2() {
311          SplittableRandom sr = new SplittableRandom();
# Line 283 | Line 331 | public class SplittableRandomTest extend
331       */
332      public void testBadStreamSize() {
333          SplittableRandom r = new SplittableRandom();
334 <        try {
335 <            java.util.stream.IntStream x = r.ints(-1L);
336 <            shouldThrow();
337 <        } catch (IllegalArgumentException ok) {
338 <        }
339 <        try {
340 <            java.util.stream.LongStream x = r.longs(-1L);
341 <            shouldThrow();
294 <        } catch (IllegalArgumentException ok) {
295 <        }
296 <        try {
297 <            java.util.stream.DoubleStream x = r.doubles(-1L);
298 <            shouldThrow();
299 <        } catch (IllegalArgumentException ok) {
300 <        }
334 >        assertThrows(
335 >            IllegalArgumentException.class,
336 >            () -> { IntStream unused = r.ints(-1L); },
337 >            () -> { IntStream unused = r.ints(-1L, 2, 3); },
338 >            () -> { LongStream unused = r.longs(-1L); },
339 >            () -> { LongStream unused = r.longs(-1L, -1L, 1L); },
340 >            () -> { DoubleStream unused = r.doubles(-1L); },
341 >            () -> { DoubleStream unused = r.doubles(-1L, .5, .6); });
342      }
343  
344      /**
# Line 306 | Line 347 | public class SplittableRandomTest extend
347       */
348      public void testBadStreamBounds() {
349          SplittableRandom r = new SplittableRandom();
350 <        try {
351 <            java.util.stream.IntStream x = r.ints(2, 1);
352 <            shouldThrow();
353 <        } catch (IllegalArgumentException ok) {
354 <        }
355 <        try {
356 <            java.util.stream.LongStream x = r.longs(1, -2);
357 <            shouldThrow();
317 <        } catch (IllegalArgumentException ok) {
318 <        }
319 <        try {
320 <            java.util.stream.DoubleStream x = r.doubles(0, 0);
321 <            shouldThrow();
322 <        } catch (IllegalArgumentException ok) {
323 <        }
350 >        assertThrows(
351 >            IllegalArgumentException.class,
352 >            () -> { IntStream unused = r.ints(2, 1); },
353 >            () -> { IntStream unused = r.ints(10, 42, 42); },
354 >            () -> { LongStream unused = r.longs(-1L, -1L); },
355 >            () -> { LongStream unused = r.longs(10, 1L, -2L); },
356 >            () -> { DoubleStream unused = r.doubles(0.0, 0.0); },
357 >            () -> { DoubleStream unused = r.doubles(10, .5, .4); });
358      }
359  
360      /**
# Line 332 | Line 366 | public class SplittableRandomTest extend
366          long size = 0;
367          for (int reps = 0; reps < REPS; ++reps) {
368              counter.reset();
369 <            r.ints(size).parallel().forEach(x -> {counter.increment();});
370 <            assertEquals(counter.sum(), size);
369 >            r.ints(size).parallel().forEach(x -> counter.increment());
370 >            assertEquals(size, counter.sum());
371              size += 524959;
372          }
373      }
# Line 347 | Line 381 | public class SplittableRandomTest extend
381          long size = 0;
382          for (int reps = 0; reps < REPS; ++reps) {
383              counter.reset();
384 <            r.longs(size).parallel().forEach(x -> {counter.increment();});
385 <            assertEquals(counter.sum(), size);
384 >            r.longs(size).parallel().forEach(x -> counter.increment());
385 >            assertEquals(size, counter.sum());
386              size += 524959;
387          }
388      }
# Line 362 | Line 396 | public class SplittableRandomTest extend
396          long size = 0;
397          for (int reps = 0; reps < REPS; ++reps) {
398              counter.reset();
399 <            r.doubles(size).parallel().forEach(x -> {counter.increment();});
400 <            assertEquals(counter.sum(), size);
399 >            r.doubles(size).parallel().forEach(x -> counter.increment());
400 >            assertEquals(size, counter.sum());
401              size += 524959;
402          }
403      }
# Line 378 | Line 412 | public class SplittableRandomTest extend
412          for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
413              for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
414                  final int lo = least, hi = bound;
415 <                r.ints(size, lo, hi).parallel().
416 <                    forEach(x -> {if (x < lo || x >= hi)
417 <                                fails.getAndIncrement(); });
415 >                r.ints(size, lo, hi).parallel().forEach(
416 >                    x -> {
417 >                        if (x < lo || x >= hi)
418 >                            fails.getAndIncrement(); });
419              }
420          }
421 <        assertEquals(fails.get(), 0);
421 >        assertEquals(0, fails.get());
422      }
423  
424      /**
# Line 396 | Line 431 | public class SplittableRandomTest extend
431          for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
432              for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
433                  final long lo = least, hi = bound;
434 <                r.longs(size, lo, hi).parallel().
435 <                    forEach(x -> {if (x < lo || x >= hi)
436 <                                fails.getAndIncrement(); });
434 >                r.longs(size, lo, hi).parallel().forEach(
435 >                    x -> {
436 >                        if (x < lo || x >= hi)
437 >                            fails.getAndIncrement(); });
438              }
439          }
440 <        assertEquals(fails.get(), 0);
440 >        assertEquals(0, fails.get());
441      }
442  
443      /**
# Line 414 | Line 450 | public class SplittableRandomTest extend
450          for (double least = 0.00011; least < 1.0e20; least *= 9) {
451              for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
452                  final double lo = least, hi = bound;
453 <                r.doubles(size, lo, hi).parallel().
454 <                    forEach(x -> {if (x < lo || x >= hi)
455 <                                fails.getAndIncrement(); });
453 >                r.doubles(size, lo, hi).parallel().forEach(
454 >                    x -> {
455 >                        if (x < lo || x >= hi)
456 >                            fails.getAndIncrement(); });
457              }
458          }
459 <        assertEquals(fails.get(), 0);
459 >        assertEquals(0, fails.get());
460 >    }
461 >
462 >    /**
463 >     * A parallel unsized stream of ints generates at least 100 values
464 >     */
465 >    public void testUnsizedIntsCount() {
466 >        LongAdder counter = new LongAdder();
467 >        SplittableRandom r = new SplittableRandom();
468 >        long size = 100;
469 >        r.ints().limit(size).parallel().forEach(x -> counter.increment());
470 >        assertEquals(size, counter.sum());
471 >    }
472 >
473 >    /**
474 >     * A parallel unsized stream of longs generates at least 100 values
475 >     */
476 >    public void testUnsizedLongsCount() {
477 >        LongAdder counter = new LongAdder();
478 >        SplittableRandom r = new SplittableRandom();
479 >        long size = 100;
480 >        r.longs().limit(size).parallel().forEach(x -> counter.increment());
481 >        assertEquals(size, counter.sum());
482 >    }
483 >
484 >    /**
485 >     * A parallel unsized stream of doubles generates at least 100 values
486 >     */
487 >    public void testUnsizedDoublesCount() {
488 >        LongAdder counter = new LongAdder();
489 >        SplittableRandom r = new SplittableRandom();
490 >        long size = 100;
491 >        r.doubles().limit(size).parallel().forEach(x -> counter.increment());
492 >        assertEquals(size, counter.sum());
493 >    }
494 >
495 >    /**
496 >     * A sequential unsized stream of ints generates at least 100 values
497 >     */
498 >    public void testUnsizedIntsCountSeq() {
499 >        LongAdder counter = new LongAdder();
500 >        SplittableRandom r = new SplittableRandom();
501 >        long size = 100;
502 >        r.ints().limit(size).forEach(x -> counter.increment());
503 >        assertEquals(size, counter.sum());
504 >    }
505 >
506 >    /**
507 >     * A sequential unsized stream of longs generates at least 100 values
508 >     */
509 >    public void testUnsizedLongsCountSeq() {
510 >        LongAdder counter = new LongAdder();
511 >        SplittableRandom r = new SplittableRandom();
512 >        long size = 100;
513 >        r.longs().limit(size).forEach(x -> counter.increment());
514 >        assertEquals(size, counter.sum());
515 >    }
516 >
517 >    /**
518 >     * A sequential unsized stream of doubles generates at least 100 values
519 >     */
520 >    public void testUnsizedDoublesCountSeq() {
521 >        LongAdder counter = new LongAdder();
522 >        SplittableRandom r = new SplittableRandom();
523 >        long size = 100;
524 >        r.doubles().limit(size).forEach(x -> counter.increment());
525 >        assertEquals(size, counter.sum());
526 >    }
527 >
528 >    /**
529 >     * SplittableRandom should implement most of Random's public methods
530 >     */
531 >    public void testShouldImplementMostRandomMethods() throws Throwable {
532 >        Predicate<Method> wasForgotten = method -> {
533 >            String name = method.getName();
534 >            // some methods deliberately not implemented
535 >            if (name.equals("setSeed")) return false;
536 >            if (name.equals("nextFloat")) return false;
537 >            if (name.equals("nextGaussian")) return false;
538 >            try {
539 >                SplittableRandom.class.getMethod(
540 >                    method.getName(), method.getParameterTypes());
541 >            } catch (ReflectiveOperationException ex) {
542 >                return true;
543 >            }
544 >            return false;
545 >        };
546 >        List<Method> forgotten =
547 >            Arrays.stream(java.util.Random.class.getMethods())
548 >            .filter(wasForgotten)
549 >            .collect(Collectors.toList());
550 >        if (!forgotten.isEmpty())
551 >            throw new AssertionError("Please implement: " + forgotten);
552 >    }
553 >
554 >    /**
555 >     * Repeated calls to nextBytes produce at least values of different signs for every byte
556 >     */
557 >    public void testNextBytes() {
558 >        SplittableRandom sr = new SplittableRandom();
559 >        int n = sr.nextInt(1, 20);
560 >        byte[] bytes = new byte[n];
561 >        outer:
562 >        for (int i = 0; i < n; i++) {
563 >            for (int tries = NCALLS; tries-->0; ) {
564 >                byte before = bytes[i];
565 >                sr.nextBytes(bytes);
566 >                byte after = bytes[i];
567 >                if (after * before < 0)
568 >                    continue outer;
569 >            }
570 >            fail("not enough variation in random bytes");
571 >        }
572 >    }
573 >
574 >    /**
575 >     * Filling an empty array with random bytes succeeds without effect.
576 >     */
577 >    public void testNextBytes_emptyArray() {
578 >        new SplittableRandom().nextBytes(new byte[0]);
579 >    }
580 >
581 >    public void testNextBytes_nullArray() {
582 >        try {
583 >            new SplittableRandom().nextBytes(null);
584 >            shouldThrow();
585 >        } catch (NullPointerException success) {}
586      }
587  
588   }

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