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root/jsr166/jsr166/src/test/tck/SplittableRandomTest.java
Revision: 1.8
Committed: Tue Sep 24 06:17:12 2013 UTC (10 years, 7 months ago) by jsr166
Branch: MAIN
Changes since 1.7: +18 -48 lines
Log Message:
use assertThrows

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 =
49 Integer.getInteger("SplittableRandomTest.reps", 4);
50
51 /**
52 * Repeated calls to nextInt produce at least two distinct results
53 */
54 public void testNextInt() {
55 SplittableRandom sr = new SplittableRandom();
56 int f = sr.nextInt();
57 int i = 0;
58 while (i < NCALLS && sr.nextInt() == f)
59 ++i;
60 assertTrue(i < NCALLS);
61 }
62
63 /**
64 * Repeated calls to nextLong produce at least two distinct results
65 */
66 public void testNextLong() {
67 SplittableRandom sr = new SplittableRandom();
68 long f = sr.nextLong();
69 int i = 0;
70 while (i < NCALLS && sr.nextLong() == f)
71 ++i;
72 assertTrue(i < NCALLS);
73 }
74
75 /**
76 * Repeated calls to nextDouble produce at least two distinct results
77 */
78 public void testNextDouble() {
79 SplittableRandom sr = new SplittableRandom();
80 double f = sr.nextDouble();
81 int i = 0;
82 while (i < NCALLS && sr.nextDouble() == f)
83 ++i;
84 assertTrue(i < NCALLS);
85 }
86
87 /**
88 * Two SplittableRandoms created with the same seed produce the
89 * same values for nextLong.
90 */
91 public void testSeedConstructor() {
92 for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
93 SplittableRandom sr1 = new SplittableRandom(seed);
94 SplittableRandom sr2 = new SplittableRandom(seed);
95 for (int i = 0; i < REPS; ++i)
96 assertEquals(sr1.nextLong(), sr2.nextLong());
97 }
98 }
99
100 /**
101 * A SplittableRandom produced by split() of a default-constructed
102 * SplittableRandom generates a different sequence
103 */
104 public void testSplit1() {
105 SplittableRandom sr = new SplittableRandom();
106 for (int reps = 0; reps < REPS; ++reps) {
107 SplittableRandom sc = sr.split();
108 int i = 0;
109 while (i < NCALLS && sr.nextLong() == sc.nextLong())
110 ++i;
111 assertTrue(i < NCALLS);
112 }
113 }
114
115 /**
116 * A SplittableRandom produced by split() of a seeded-constructed
117 * SplittableRandom generates a different sequence
118 */
119 public void testSplit2() {
120 SplittableRandom sr = new SplittableRandom(12345);
121 for (int reps = 0; reps < REPS; ++reps) {
122 SplittableRandom sc = sr.split();
123 int i = 0;
124 while (i < NCALLS && sr.nextLong() == sc.nextLong())
125 ++i;
126 assertTrue(i < NCALLS);
127 }
128 }
129
130 /**
131 * nextInt(negative) throws IllegalArgumentException
132 */
133 public void testNextIntBoundedNeg() {
134 SplittableRandom sr = new SplittableRandom();
135 try {
136 int f = sr.nextInt(-17);
137 shouldThrow();
138 } catch (IllegalArgumentException success) {}
139 }
140
141 /**
142 * nextInt(least >= bound) throws IllegalArgumentException
143 */
144 public void testNextIntBadBounds() {
145 SplittableRandom sr = new SplittableRandom();
146 try {
147 int f = sr.nextInt(17, 2);
148 shouldThrow();
149 } catch (IllegalArgumentException success) {}
150 }
151
152 /**
153 * nextInt(bound) returns 0 <= value < bound;
154 * repeated calls produce at least two distinct results
155 */
156 public void testNextIntBounded() {
157 SplittableRandom sr = new SplittableRandom();
158 // sample bound space across prime number increments
159 for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
160 int f = sr.nextInt(bound);
161 assertTrue(0 <= f && f < bound);
162 int i = 0;
163 int j;
164 while (i < NCALLS &&
165 (j = sr.nextInt(bound)) == f) {
166 assertTrue(0 <= j && j < bound);
167 ++i;
168 }
169 assertTrue(i < NCALLS);
170 }
171 }
172
173 /**
174 * nextInt(least, bound) returns least <= value < bound;
175 * repeated calls produce at least two distinct results
176 */
177 public void testNextIntBounded2() {
178 SplittableRandom sr = new SplittableRandom();
179 for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
180 for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
181 int f = sr.nextInt(least, bound);
182 assertTrue(least <= f && f < bound);
183 int i = 0;
184 int j;
185 while (i < NCALLS &&
186 (j = sr.nextInt(least, bound)) == f) {
187 assertTrue(least <= j && j < bound);
188 ++i;
189 }
190 assertTrue(i < NCALLS);
191 }
192 }
193 }
194
195 /**
196 * nextLong(negative) throws IllegalArgumentException
197 */
198 public void testNextLongBoundedNeg() {
199 SplittableRandom sr = new SplittableRandom();
200 try {
201 long f = sr.nextLong(-17);
202 shouldThrow();
203 } catch (IllegalArgumentException success) {}
204 }
205
206 /**
207 * nextLong(least >= bound) throws IllegalArgumentException
208 */
209 public void testNextLongBadBounds() {
210 SplittableRandom sr = new SplittableRandom();
211 try {
212 long f = sr.nextLong(17, 2);
213 shouldThrow();
214 } catch (IllegalArgumentException success) {}
215 }
216
217 /**
218 * nextLong(bound) returns 0 <= value < bound;
219 * repeated calls produce at least two distinct results
220 */
221 public void testNextLongBounded() {
222 SplittableRandom sr = new SplittableRandom();
223 for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
224 long f = sr.nextLong(bound);
225 assertTrue(0 <= f && f < bound);
226 int i = 0;
227 long j;
228 while (i < NCALLS &&
229 (j = sr.nextLong(bound)) == f) {
230 assertTrue(0 <= j && j < bound);
231 ++i;
232 }
233 assertTrue(i < NCALLS);
234 }
235 }
236
237 /**
238 * nextLong(least, bound) returns least <= value < bound;
239 * repeated calls produce at least two distinct results
240 */
241 public void testNextLongBounded2() {
242 SplittableRandom sr = new SplittableRandom();
243 for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
244 for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
245 long f = sr.nextLong(least, bound);
246 assertTrue(least <= f && f < bound);
247 int i = 0;
248 long j;
249 while (i < NCALLS &&
250 (j = sr.nextLong(least, bound)) == f) {
251 assertTrue(least <= j && j < bound);
252 ++i;
253 }
254 assertTrue(i < NCALLS);
255 }
256 }
257 }
258
259 /**
260 * nextDouble(least, bound) returns least <= value < bound;
261 * repeated calls produce at least two distinct results
262 */
263 public void testNextDoubleBounded2() {
264 SplittableRandom sr = new SplittableRandom();
265 for (double least = 0.0001; least < 1.0e20; least *= 8) {
266 for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
267 double f = sr.nextDouble(least, bound);
268 assertTrue(least <= f && f < bound);
269 int i = 0;
270 double j;
271 while (i < NCALLS &&
272 (j = sr.nextDouble(least, bound)) == f) {
273 assertTrue(least <= j && j < bound);
274 ++i;
275 }
276 assertTrue(i < NCALLS);
277 }
278 }
279 }
280
281 /**
282 * Invoking sized ints, long, doubles, with negative sizes throws
283 * IllegalArgumentException
284 */
285 public void testBadStreamSize() {
286 SplittableRandom r = new SplittableRandom();
287 Runnable[] throwingActions = {
288 () -> { java.util.stream.IntStream x = r.ints(-1L); },
289 () -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
290 () -> { java.util.stream.LongStream x = r.longs(-1L); },
291 () -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
292 () -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
293 () -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
294 };
295 assertThrows(IllegalArgumentException.class, throwingActions);
296 }
297
298 /**
299 * Invoking bounded ints, long, doubles, with illegal bounds throws
300 * IllegalArgumentException
301 */
302 public void testBadStreamBounds() {
303 SplittableRandom r = new SplittableRandom();
304 Runnable[] throwingActions = {
305 () -> { java.util.stream.IntStream x = r.ints(2, 1); },
306 () -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
307 () -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
308 () -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
309 () -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
310 () -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
311 };
312 assertThrows(IllegalArgumentException.class, throwingActions);
313 }
314
315 /**
316 * A parallel sized stream of ints generates the given number of values
317 */
318 public void testIntsCount() {
319 LongAdder counter = new LongAdder();
320 SplittableRandom r = new SplittableRandom();
321 long size = 0;
322 for (int reps = 0; reps < REPS; ++reps) {
323 counter.reset();
324 r.ints(size).parallel().forEach(x -> counter.increment());
325 assertEquals(size, counter.sum());
326 size += 524959;
327 }
328 }
329
330 /**
331 * A parallel sized stream of longs generates the given number of values
332 */
333 public void testLongsCount() {
334 LongAdder counter = new LongAdder();
335 SplittableRandom r = new SplittableRandom();
336 long size = 0;
337 for (int reps = 0; reps < REPS; ++reps) {
338 counter.reset();
339 r.longs(size).parallel().forEach(x -> counter.increment());
340 assertEquals(size, counter.sum());
341 size += 524959;
342 }
343 }
344
345 /**
346 * A parallel sized stream of doubles generates the given number of values
347 */
348 public void testDoublesCount() {
349 LongAdder counter = new LongAdder();
350 SplittableRandom r = new SplittableRandom();
351 long size = 0;
352 for (int reps = 0; reps < REPS; ++reps) {
353 counter.reset();
354 r.doubles(size).parallel().forEach(x -> counter.increment());
355 assertEquals(size, counter.sum());
356 size += 524959;
357 }
358 }
359
360 /**
361 * Each of a parallel sized stream of bounded ints is within bounds
362 */
363 public void testBoundedInts() {
364 AtomicInteger fails = new AtomicInteger(0);
365 SplittableRandom r = new SplittableRandom();
366 long size = 12345L;
367 for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
368 for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
369 final int lo = least, hi = bound;
370 r.ints(size, lo, hi).parallel().
371 forEach(x -> {if (x < lo || x >= hi)
372 fails.getAndIncrement(); });
373 }
374 }
375 assertEquals(0, fails.get());
376 }
377
378 /**
379 * Each of a parallel sized stream of bounded longs is within bounds
380 */
381 public void testBoundedLongs() {
382 AtomicInteger fails = new AtomicInteger(0);
383 SplittableRandom r = new SplittableRandom();
384 long size = 123L;
385 for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
386 for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
387 final long lo = least, hi = bound;
388 r.longs(size, lo, hi).parallel().
389 forEach(x -> {if (x < lo || x >= hi)
390 fails.getAndIncrement(); });
391 }
392 }
393 assertEquals(0, fails.get());
394 }
395
396 /**
397 * Each of a parallel sized stream of bounded doubles is within bounds
398 */
399 public void testBoundedDoubles() {
400 AtomicInteger fails = new AtomicInteger(0);
401 SplittableRandom r = new SplittableRandom();
402 long size = 456;
403 for (double least = 0.00011; least < 1.0e20; least *= 9) {
404 for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
405 final double lo = least, hi = bound;
406 r.doubles(size, lo, hi).parallel().
407 forEach(x -> {if (x < lo || x >= hi)
408 fails.getAndIncrement(); });
409 }
410 }
411 assertEquals(0, fails.get());
412 }
413
414 /**
415 * A parallel unsized stream of ints generates at least 100 values
416 */
417 public void testUnsizedIntsCount() {
418 LongAdder counter = new LongAdder();
419 SplittableRandom r = new SplittableRandom();
420 long size = 100;
421 r.ints().limit(size).parallel().forEach(x -> counter.increment());
422 assertEquals(size, counter.sum());
423 }
424
425 /**
426 * A parallel unsized stream of longs generates at least 100 values
427 */
428 public void testUnsizedLongsCount() {
429 LongAdder counter = new LongAdder();
430 SplittableRandom r = new SplittableRandom();
431 long size = 100;
432 r.longs().limit(size).parallel().forEach(x -> counter.increment());
433 assertEquals(size, counter.sum());
434 }
435
436 /**
437 * A parallel unsized stream of doubles generates at least 100 values
438 */
439 public void testUnsizedDoublesCount() {
440 LongAdder counter = new LongAdder();
441 SplittableRandom r = new SplittableRandom();
442 long size = 100;
443 r.doubles().limit(size).parallel().forEach(x -> counter.increment());
444 assertEquals(size, counter.sum());
445 }
446
447 /**
448 * A sequential unsized stream of ints generates at least 100 values
449 */
450 public void testUnsizedIntsCountSeq() {
451 LongAdder counter = new LongAdder();
452 SplittableRandom r = new SplittableRandom();
453 long size = 100;
454 r.ints().limit(size).forEach(x -> counter.increment());
455 assertEquals(size, counter.sum());
456 }
457
458 /**
459 * A sequential unsized stream of longs generates at least 100 values
460 */
461 public void testUnsizedLongsCountSeq() {
462 LongAdder counter = new LongAdder();
463 SplittableRandom r = new SplittableRandom();
464 long size = 100;
465 r.longs().limit(size).forEach(x -> counter.increment());
466 assertEquals(size, counter.sum());
467 }
468
469 /**
470 * A sequential unsized stream of doubles generates at least 100 values
471 */
472 public void testUnsizedDoublesCountSeq() {
473 LongAdder counter = new LongAdder();
474 SplittableRandom r = new SplittableRandom();
475 long size = 100;
476 r.doubles().limit(size).forEach(x -> counter.increment());
477 assertEquals(size, counter.sum());
478 }
479
480 }