--- jsr166/src/test/tck/ThreadLocalRandomTest.java 2010/08/25 00:07:03 1.7 +++ jsr166/src/test/tck/ThreadLocalRandomTest.java 2014/12/31 19:05:43 1.20 @@ -1,12 +1,15 @@ /* * 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/licenses/publicdomain + * http://creativecommons.org/publicdomain/zero/1.0/ */ -import junit.framework.*; -import java.util.concurrent.*; -import java.util.*; +import java.util.concurrent.ThreadLocalRandom; +import java.util.concurrent.atomic.AtomicLong; +import java.util.concurrent.atomic.AtomicReference; + +import junit.framework.Test; +import junit.framework.TestSuite; public class ThreadLocalRandomTest extends JSR166TestCase { @@ -17,7 +20,7 @@ public class ThreadLocalRandomTest exten return new TestSuite(ThreadLocalRandomTest.class); } - /** + /* * Testing coverage notes: * * We don't test randomness properties, but only that repeated @@ -26,15 +29,18 @@ public class ThreadLocalRandomTest exten * across multiples of primes. */ - // + // 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 << 28); - // Max sampled long bound + // max sampled long bound static final long MAX_LONG_BOUND = (1L << 42); + // Number of replications for other checks + static final int REPS = 20; + /** * setSeed throws UnsupportedOperationException */ @@ -46,7 +52,7 @@ public class ThreadLocalRandomTest exten } /** - * Repeated calls to nextInt produce at least one different result + * Repeated calls to nextInt produce at least two distinct results */ public void testNextInt() { int f = ThreadLocalRandom.current().nextInt(); @@ -57,7 +63,7 @@ public class ThreadLocalRandomTest exten } /** - * Repeated calls to nextLong produce at least one different result + * Repeated calls to nextLong produce at least two distinct results */ public void testNextLong() { long f = ThreadLocalRandom.current().nextLong(); @@ -67,9 +73,8 @@ public class ThreadLocalRandomTest exten assertTrue(i < NCALLS); } - /** - * Repeated calls to nextBoolean produce at least one different result + * Repeated calls to nextBoolean produce at least two distinct results */ public void testNextBoolean() { boolean f = ThreadLocalRandom.current().nextBoolean(); @@ -80,7 +85,7 @@ public class ThreadLocalRandomTest exten } /** - * Repeated calls to nextFloat produce at least one different result + * Repeated calls to nextFloat produce at least two distinct results */ public void testNextFloat() { float f = ThreadLocalRandom.current().nextFloat(); @@ -91,18 +96,18 @@ public class ThreadLocalRandomTest exten } /** - * Repeated calls to nextDouble produce at least one different result + * Repeated calls to nextDouble produce at least two distinct results */ public void testNextDouble() { double f = ThreadLocalRandom.current().nextDouble(); - double i = 0; + int i = 0; while (i < NCALLS && ThreadLocalRandom.current().nextDouble() == f) ++i; assertTrue(i < NCALLS); } /** - * Repeated calls to nextGaussian produce at least one different result + * Repeated calls to nextGaussian produce at least two distinct results */ public void testNextGaussian() { double f = ThreadLocalRandom.current().nextGaussian(); @@ -112,31 +117,40 @@ public class ThreadLocalRandomTest exten assertTrue(i < NCALLS); } - /** - * nextInt(negative) throws IllegalArgumentException; + * nextInt(non-positive) throws IllegalArgumentException */ - public void testNextIntBoundedNeg() { - try { - int f = ThreadLocalRandom.current().nextInt(-17); - shouldThrow(); - } catch (IllegalArgumentException success) {} + public void testNextIntBoundNonPositive() { + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + for (int bound : new int[] { 0, -17, Integer.MIN_VALUE }) { + try { + rnd.nextInt(bound); + shouldThrow(); + } catch (IllegalArgumentException success) {} + } } /** - * nextInt(least >= bound) throws IllegalArgumentException; + * nextInt(least >= bound) throws IllegalArgumentException */ public void testNextIntBadBounds() { - try { - int f = ThreadLocalRandom.current().nextInt(17, 2); - shouldThrow(); - } catch (IllegalArgumentException success) {} + int[][] badBoundss = { + { 17, 2 }, + { -42, -42 }, + { Integer.MAX_VALUE, Integer.MIN_VALUE }, + }; + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + for (int[] badBounds : badBoundss) { + try { + rnd.nextInt(badBounds[0], badBounds[1]); + shouldThrow(); + } catch (IllegalArgumentException success) {} + } } - /** * nextInt(bound) returns 0 <= value < bound; - * repeated calls produce at least one different result + * repeated calls produce at least two distinct results */ public void testNextIntBounded() { // sample bound space across prime number increments @@ -154,10 +168,9 @@ public class ThreadLocalRandomTest exten } } - /** * nextInt(least, bound) returns least <= value < bound; - * repeated calls produce at least one different result + * repeated calls produce at least two distinct results */ public void testNextIntBounded2() { for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) { @@ -177,28 +190,39 @@ public class ThreadLocalRandomTest exten } /** - * nextLong(negative) throws IllegalArgumentException; + * nextLong(non-positive) throws IllegalArgumentException */ - public void testNextLongBoundedNeg() { - try { - long f = ThreadLocalRandom.current().nextLong(-17); - shouldThrow(); - } catch (IllegalArgumentException success) {} + public void testNextLongBoundNonPositive() { + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + for (long bound : new long[] { 0L, -17L, Long.MIN_VALUE }) { + try { + rnd.nextLong(bound); + shouldThrow(); + } catch (IllegalArgumentException success) {} + } } /** - * nextLong(least >= bound) throws IllegalArgumentException; + * nextLong(least >= bound) throws IllegalArgumentException */ public void testNextLongBadBounds() { - try { - long f = ThreadLocalRandom.current().nextLong(17, 2); - shouldThrow(); - } catch (IllegalArgumentException success) {} + long[][] badBoundss = { + { 17L, 2L }, + { -42L, -42L }, + { Long.MAX_VALUE, Long.MIN_VALUE }, + }; + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + for (long[] badBounds : badBoundss) { + try { + rnd.nextLong(badBounds[0], badBounds[1]); + shouldThrow(); + } catch (IllegalArgumentException success) {} + } } /** * nextLong(bound) returns 0 <= value < bound; - * repeated calls produce at least one different result + * repeated calls produce at least two distinct results */ public void testNextLongBounded() { for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) { @@ -217,7 +241,7 @@ public class ThreadLocalRandomTest exten /** * nextLong(least, bound) returns least <= value < bound; - * repeated calls produce at least one different result + * repeated calls produce at least two distinct results */ public void testNextLongBounded2() { for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) { @@ -236,10 +260,29 @@ public class ThreadLocalRandomTest exten } } + /** + * nextDouble(non-positive) throws IllegalArgumentException + */ + public void testNextDoubleBoundNonPositive() { + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + double[] badBounds = { + 0.0d, + -17.0d, + -Double.MIN_VALUE, + Double.NEGATIVE_INFINITY, + Double.NaN, + }; + for (double bound : badBounds) { + try { + rnd.nextDouble(bound); + shouldThrow(); + } catch (IllegalArgumentException success) {} + } + } /** * nextDouble(least, bound) returns least <= value < bound; - * repeated calls produce at least one different result + * repeated calls produce at least two distinct results */ public void testNextDoubleBounded2() { for (double least = 0.0001; least < 1.0e20; least *= 8) { @@ -258,5 +301,41 @@ public class ThreadLocalRandomTest exten } } + /** + * Different threads produce different pseudo-random sequences + */ + public void testDifferentSequences() { + // Don't use main thread's ThreadLocalRandom - it is likely to + // be polluted by previous tests. + final AtomicReference threadLocalRandom = + new AtomicReference(); + final AtomicLong rand = new AtomicLong(); + + long firstRand = 0; + ThreadLocalRandom firstThreadLocalRandom = null; + + Runnable getRandomState = new CheckedRunnable() { + public void realRun() { + ThreadLocalRandom current = ThreadLocalRandom.current(); + assertSame(current, ThreadLocalRandom.current()); + // test bug: the following is not guaranteed and not true in JDK8 + // assertNotSame(current, threadLocalRandom.get()); + rand.set(current.nextLong()); + threadLocalRandom.set(current); + }}; + + Thread first = newStartedThread(getRandomState); + awaitTermination(first); + firstRand = rand.get(); + firstThreadLocalRandom = threadLocalRandom.get(); + + for (int i = 0; i < NCALLS; i++) { + Thread t = newStartedThread(getRandomState); + awaitTermination(t); + if (firstRand != rand.get()) + return; + } + fail("all threads generate the same pseudo-random sequence"); + } }