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root/jsr166/jsr166/src/test/tck/SplittableRandomTest.java
Revision: 1.4
Committed: Sun Jul 14 16:55:01 2013 UTC (10 years, 10 months ago) by jsr166
Branch: MAIN
Changes since 1.3: +42 -52 lines
Log Message:
actually test SplittableRandom; tidying pass; coding style consistency

File Contents

# Content
1 /*
2 * Written by Doug Lea with assistance from members of JCP JSR-166
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.*;
8 import java.util.SplittableRandom;
9 import java.util.concurrent.atomic.AtomicInteger;
10 import java.util.concurrent.atomic.AtomicLong;
11 import java.util.concurrent.atomic.LongAdder;
12
13 public class SplittableRandomTest extends JSR166TestCase {
14
15 public static void main(String[] args) {
16 junit.textui.TestRunner.run(suite());
17 }
18 public static Test suite() {
19 return new TestSuite(SplittableRandomTest.class);
20 }
21
22 /*
23 * Testing coverage notes:
24 *
25 * 1. Many of the test methods are adapted from ThreadLocalRandomTest.
26 *
27 * 2. These tests do not check for random number generator quality.
28 * But we check for minimal API compliance by requiring that
29 * repeated calls to nextX methods, up to NCALLS tries, produce at
30 * least two distinct results. (In some possible universe, a
31 * "correct" implementation might fail, but the odds are vastly
32 * less than that of encountering a hardware failure while running
33 * the test.) For bounded nextX methods, we sample various
34 * intervals across multiples of primes. In other tests, we repeat
35 * under REPS different values.
36 */
37
38 // max numbers of calls to detect getting stuck on one value
39 static final int NCALLS = 10000;
40
41 // max sampled int bound
42 static final int MAX_INT_BOUND = (1 << 28);
43
44 // max sampled long bound
45 static final long MAX_LONG_BOUND = (1L << 42);
46
47 // Number of replications for other checks
48 static final int REPS = 20;
49
50 /**
51 * Repeated calls to nextInt produce at least two distinct results
52 */
53 public void testNextInt() {
54 SplittableRandom sr = new SplittableRandom();
55 int f = sr.nextInt();
56 int i = 0;
57 while (i < NCALLS && sr.nextInt() == f)
58 ++i;
59 assertTrue(i < NCALLS);
60 }
61
62 /**
63 * Repeated calls to nextLong produce at least two distinct results
64 */
65 public void testNextLong() {
66 SplittableRandom sr = new SplittableRandom();
67 long f = sr.nextLong();
68 int i = 0;
69 while (i < NCALLS && sr.nextLong() == f)
70 ++i;
71 assertTrue(i < NCALLS);
72 }
73
74 /**
75 * Repeated calls to nextDouble produce at least two distinct results
76 */
77 public void testNextDouble() {
78 SplittableRandom sr = new SplittableRandom();
79 double f = sr.nextDouble();
80 int i = 0;
81 while (i < NCALLS && sr.nextDouble() == f)
82 ++i;
83 assertTrue(i < NCALLS);
84 }
85
86 /**
87 * Two SplittableRandoms created with the same seed produce the
88 * same values for nextLong.
89 */
90 public void testSeedConstructor() {
91 for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
92 SplittableRandom sr1 = new SplittableRandom(seed);
93 SplittableRandom sr2 = new SplittableRandom(seed);
94 for (int i = 0; i < REPS; ++i)
95 assertEquals(sr1.nextLong(), sr2.nextLong());
96 }
97 }
98
99 /**
100 * A SplittableRandom produced by split() of a default-constructed
101 * SplittableRandom generates a different sequence
102 */
103 public void testSplit1() {
104 SplittableRandom sr = new SplittableRandom();
105 for (int reps = 0; reps < REPS; ++reps) {
106 SplittableRandom sc = sr.split();
107 int i = 0;
108 while (i < NCALLS && sr.nextLong() == sc.nextLong())
109 ++i;
110 assertTrue(i < NCALLS);
111 }
112 }
113
114 /**
115 * A SplittableRandom produced by split() of a seeded-constructed
116 * SplittableRandom generates a different sequence
117 */
118 public void testSplit2() {
119 SplittableRandom sr = new SplittableRandom(12345);
120 for (int reps = 0; reps < REPS; ++reps) {
121 SplittableRandom sc = sr.split();
122 int i = 0;
123 while (i < NCALLS && sr.nextLong() == sc.nextLong())
124 ++i;
125 assertTrue(i < NCALLS);
126 }
127 }
128
129 /**
130 * nextInt(negative) throws IllegalArgumentException
131 */
132 public void testNextIntBoundedNeg() {
133 SplittableRandom sr = new SplittableRandom();
134 try {
135 int f = sr.nextInt(-17);
136 shouldThrow();
137 } catch (IllegalArgumentException success) {}
138 }
139
140 /**
141 * nextInt(least >= bound) throws IllegalArgumentException
142 */
143 public void testNextIntBadBounds() {
144 SplittableRandom sr = new SplittableRandom();
145 try {
146 int f = sr.nextInt(17, 2);
147 shouldThrow();
148 } catch (IllegalArgumentException success) {}
149 }
150
151 /**
152 * nextInt(bound) returns 0 <= value < bound;
153 * repeated calls produce at least two distinct results
154 */
155 public void testNextIntBounded() {
156 SplittableRandom sr = new SplittableRandom();
157 // sample bound space across prime number increments
158 for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
159 int f = sr.nextInt(bound);
160 assertTrue(0 <= f && f < bound);
161 int i = 0;
162 int j;
163 while (i < NCALLS &&
164 (j = sr.nextInt(bound)) == f) {
165 assertTrue(0 <= j && j < bound);
166 ++i;
167 }
168 assertTrue(i < NCALLS);
169 }
170 }
171
172 /**
173 * nextInt(least, bound) returns least <= value < bound;
174 * repeated calls produce at least two distinct results
175 */
176 public void testNextIntBounded2() {
177 SplittableRandom sr = new SplittableRandom();
178 for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
179 for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
180 int f = sr.nextInt(least, bound);
181 assertTrue(least <= f && f < bound);
182 int i = 0;
183 int j;
184 while (i < NCALLS &&
185 (j = sr.nextInt(least, bound)) == f) {
186 assertTrue(least <= j && j < bound);
187 ++i;
188 }
189 assertTrue(i < NCALLS);
190 }
191 }
192 }
193
194 /**
195 * nextLong(negative) throws IllegalArgumentException
196 */
197 public void testNextLongBoundedNeg() {
198 SplittableRandom sr = new SplittableRandom();
199 try {
200 long f = sr.nextLong(-17);
201 shouldThrow();
202 } catch (IllegalArgumentException success) {}
203 }
204
205 /**
206 * nextLong(least >= bound) throws IllegalArgumentException
207 */
208 public void testNextLongBadBounds() {
209 SplittableRandom sr = new SplittableRandom();
210 try {
211 long f = sr.nextLong(17, 2);
212 shouldThrow();
213 } catch (IllegalArgumentException success) {}
214 }
215
216 /**
217 * nextLong(bound) returns 0 <= value < bound;
218 * repeated calls produce at least two distinct results
219 */
220 public void testNextLongBounded() {
221 SplittableRandom sr = new SplittableRandom();
222 for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
223 long f = sr.nextLong(bound);
224 assertTrue(0 <= f && f < bound);
225 int i = 0;
226 long j;
227 while (i < NCALLS &&
228 (j = sr.nextLong(bound)) == f) {
229 assertTrue(0 <= j && j < bound);
230 ++i;
231 }
232 assertTrue(i < NCALLS);
233 }
234 }
235
236 /**
237 * nextLong(least, bound) returns least <= value < bound;
238 * repeated calls produce at least two distinct results
239 */
240 public void testNextLongBounded2() {
241 SplittableRandom sr = new SplittableRandom();
242 for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
243 for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
244 long f = sr.nextLong(least, bound);
245 assertTrue(least <= f && f < bound);
246 int i = 0;
247 long j;
248 while (i < NCALLS &&
249 (j = sr.nextLong(least, bound)) == f) {
250 assertTrue(least <= j && j < bound);
251 ++i;
252 }
253 assertTrue(i < NCALLS);
254 }
255 }
256 }
257
258 /**
259 * nextDouble(least, bound) returns least <= value < bound;
260 * repeated calls produce at least two distinct results
261 */
262 public void testNextDoubleBounded2() {
263 SplittableRandom sr = new SplittableRandom();
264 for (double least = 0.0001; least < 1.0e20; least *= 8) {
265 for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
266 double f = sr.nextDouble(least, bound);
267 assertTrue(least <= f && f < bound);
268 int i = 0;
269 double j;
270 while (i < NCALLS &&
271 (j = sr.nextDouble(least, bound)) == f) {
272 assertTrue(least <= j && j < bound);
273 ++i;
274 }
275 assertTrue(i < NCALLS);
276 }
277 }
278 }
279
280 /**
281 * Invoking sized ints, long, doubles, with negative sizes throws
282 * IllegalArgumentException
283 */
284 public void testBadStreamSize() {
285 SplittableRandom r = new SplittableRandom();
286 try {
287 java.util.stream.IntStream x = r.ints(-1L);
288 shouldThrow();
289 } catch (IllegalArgumentException success) {}
290 try {
291 java.util.stream.LongStream x = r.longs(-1L);
292 shouldThrow();
293 } catch (IllegalArgumentException success) {}
294 try {
295 java.util.stream.DoubleStream x = r.doubles(-1L);
296 shouldThrow();
297 } catch (IllegalArgumentException success) {}
298 }
299
300 /**
301 * Invoking bounded ints, long, doubles, with illegal bounds throws
302 * IllegalArgumentException
303 */
304 public void testBadStreamBounds() {
305 SplittableRandom r = new SplittableRandom();
306 try {
307 java.util.stream.IntStream x = r.ints(2, 1);
308 shouldThrow();
309 } catch (IllegalArgumentException success) {}
310 try {
311 java.util.stream.LongStream x = r.longs(1, -2);
312 shouldThrow();
313 } catch (IllegalArgumentException success) {}
314 try {
315 java.util.stream.DoubleStream x = r.doubles(0, 0);
316 shouldThrow();
317 } catch (IllegalArgumentException success) {}
318 }
319
320 /**
321 * A parallel sized stream of ints generates the given number of values
322 */
323 public void testIntsCount() {
324 LongAdder counter = new LongAdder();
325 SplittableRandom r = new SplittableRandom();
326 long size = 0;
327 for (int reps = 0; reps < REPS; ++reps) {
328 counter.reset();
329 r.ints(size).parallel().forEach(x -> {counter.increment();});
330 assertEquals(size, counter.sum());
331 size += 524959;
332 }
333 }
334
335 /**
336 * A parallel sized stream of longs generates the given number of values
337 */
338 public void testLongsCount() {
339 LongAdder counter = new LongAdder();
340 SplittableRandom r = new SplittableRandom();
341 long size = 0;
342 for (int reps = 0; reps < REPS; ++reps) {
343 counter.reset();
344 r.longs(size).parallel().forEach(x -> {counter.increment();});
345 assertEquals(size, counter.sum());
346 size += 524959;
347 }
348 }
349
350 /**
351 * A parallel sized stream of doubles generates the given number of values
352 */
353 public void testDoublesCount() {
354 LongAdder counter = new LongAdder();
355 SplittableRandom r = new SplittableRandom();
356 long size = 0;
357 for (int reps = 0; reps < REPS; ++reps) {
358 counter.reset();
359 r.doubles(size).parallel().forEach(x -> {counter.increment();});
360 assertEquals(size, counter.sum());
361 size += 524959;
362 }
363 }
364
365 /**
366 * Each of a parallel sized stream of bounded ints is within bounds
367 */
368 public void testBoundedInts() {
369 AtomicInteger fails = new AtomicInteger(0);
370 SplittableRandom r = new SplittableRandom();
371 long size = 12345L;
372 for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
373 for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
374 final int lo = least, hi = bound;
375 r.ints(size, lo, hi).parallel().
376 forEach(x -> {if (x < lo || x >= hi)
377 fails.getAndIncrement(); });
378 }
379 }
380 assertEquals(0, fails.get());
381 }
382
383 /**
384 * Each of a parallel sized stream of bounded longs is within bounds
385 */
386 public void testBoundedLongs() {
387 AtomicInteger fails = new AtomicInteger(0);
388 SplittableRandom r = new SplittableRandom();
389 long size = 123L;
390 for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
391 for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
392 final long lo = least, hi = bound;
393 r.longs(size, lo, hi).parallel().
394 forEach(x -> {if (x < lo || x >= hi)
395 fails.getAndIncrement(); });
396 }
397 }
398 assertEquals(0, fails.get());
399 }
400
401 /**
402 * Each of a parallel sized stream of bounded doubles is within bounds
403 */
404 public void testBoundedDoubles() {
405 AtomicInteger fails = new AtomicInteger(0);
406 SplittableRandom r = new SplittableRandom();
407 long size = 456;
408 for (double least = 0.00011; least < 1.0e20; least *= 9) {
409 for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
410 final double lo = least, hi = bound;
411 r.doubles(size, lo, hi).parallel().
412 forEach(x -> {if (x < lo || x >= hi)
413 fails.getAndIncrement(); });
414 }
415 }
416 assertEquals(0, fails.get());
417 }
418
419 /**
420 * A parallel unsized stream of ints generates at least 100 values
421 */
422 public void testUnsizedIntsCount() {
423 LongAdder counter = new LongAdder();
424 SplittableRandom r = new SplittableRandom();
425 long size = 100;
426 r.ints().limit(size).parallel().forEach(x -> {counter.increment();});
427 assertEquals(size, counter.sum());
428 }
429
430 /**
431 * A parallel unsized stream of longs generates at least 100 values
432 */
433 public void testUnsizedLongsCount() {
434 LongAdder counter = new LongAdder();
435 SplittableRandom r = new SplittableRandom();
436 long size = 100;
437 r.longs().limit(size).parallel().forEach(x -> {counter.increment();});
438 assertEquals(size, counter.sum());
439 }
440
441 /**
442 * A parallel unsized stream of doubles generates at least 100 values
443 */
444 public void testUnsizedDoublesCount() {
445 LongAdder counter = new LongAdder();
446 SplittableRandom r = new SplittableRandom();
447 long size = 100;
448 r.doubles().limit(size).parallel().forEach(x -> {counter.increment();});
449 assertEquals(size, counter.sum());
450 }
451
452 /**
453 * A sequential unsized stream of ints generates at least 100 values
454 */
455 public void testUnsizedIntsCountSeq() {
456 LongAdder counter = new LongAdder();
457 SplittableRandom r = new SplittableRandom();
458 long size = 100;
459 r.ints().limit(size).forEach(x -> {counter.increment();});
460 assertEquals(size, counter.sum());
461 }
462
463 /**
464 * A sequential unsized stream of longs generates at least 100 values
465 */
466 public void testUnsizedLongsCountSeq() {
467 LongAdder counter = new LongAdder();
468 SplittableRandom r = new SplittableRandom();
469 long size = 100;
470 r.longs().limit(size).forEach(x -> {counter.increment();});
471 assertEquals(size, counter.sum());
472 }
473
474 /**
475 * A sequential unsized stream of doubles generates at least 100 values
476 */
477 public void testUnsizedDoublesCountSeq() {
478 LongAdder counter = new LongAdder();
479 SplittableRandom r = new SplittableRandom();
480 long size = 100;
481 r.doubles().limit(size).forEach(x -> {counter.increment();});
482 assertEquals(size, counter.sum());
483 }
484
485 }