--- jsr166/src/test/tck/ThreadLocalRandomTest.java 2009/07/31 23:02:50 1.1 +++ jsr166/src/test/tck/ThreadLocalRandomTest.java 2011/06/03 21:36:55 1.11 @@ -1,32 +1,33 @@ /* * 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; public class ThreadLocalRandomTest extends JSR166TestCase { public static void main(String[] args) { - junit.textui.TestRunner.run (suite()); + junit.textui.TestRunner.run(suite()); } public static Test suite() { - return new TestSuite(ThreadLocalRandomTest.class); + return new TestSuite(ThreadLocalRandomTest.class); } /** * Testing coverage notes: - * + * * We don't test randomness properties, but only that repeated * calls, up to NCALLS tries, produce at least one different * result. For bounded versions, we sample various intervals * across multiples of primes. */ - // + // static final int NCALLS = 10000; // max sampled int bound @@ -41,8 +42,8 @@ public class ThreadLocalRandomTest exten public void testSetSeed() { try { ThreadLocalRandom.current().setSeed(17); - } catch(UnsupportedOperationException success) { - } + shouldThrow(); + } catch (UnsupportedOperationException success) {} } /** @@ -67,7 +68,6 @@ public class ThreadLocalRandomTest exten assertTrue(i < NCALLS); } - /** * Repeated calls to nextBoolean produce at least one different result */ @@ -112,15 +112,14 @@ public class ThreadLocalRandomTest exten assertTrue(i < NCALLS); } - /** * nextInt(negative) throws IllegalArgumentException; */ public void testNextIntBoundedNeg() { try { - int f = ThreadLocalRandom.current().nextInt(-17); - } catch(IllegalArgumentException success) { - } + int f = ThreadLocalRandom.current().nextInt(-17); + shouldThrow(); + } catch (IllegalArgumentException success) {} } /** @@ -128,12 +127,11 @@ public class ThreadLocalRandomTest exten */ public void testNextIntBadBounds() { try { - int f = ThreadLocalRandom.current().nextInt(17, 2); - } catch(IllegalArgumentException success) { - } + int f = ThreadLocalRandom.current().nextInt(17, 2); + shouldThrow(); + } catch (IllegalArgumentException success) {} } - /** * nextInt(bound) returns 0 <= value < bound; * repeated calls produce at least one different result @@ -145,7 +143,7 @@ public class ThreadLocalRandomTest exten assertTrue(0 <= f && f < bound); int i = 0; int j; - while (i < NCALLS && + while (i < NCALLS && (j = ThreadLocalRandom.current().nextInt(bound)) == f) { assertTrue(0 <= j && j < bound); ++i; @@ -154,7 +152,6 @@ public class ThreadLocalRandomTest exten } } - /** * nextInt(least, bound) returns least <= value < bound; * repeated calls produce at least one different result @@ -166,7 +163,7 @@ public class ThreadLocalRandomTest exten assertTrue(least <= f && f < bound); int i = 0; int j; - while (i < NCALLS && + while (i < NCALLS && (j = ThreadLocalRandom.current().nextInt(least, bound)) == f) { assertTrue(least <= j && j < bound); ++i; @@ -181,9 +178,9 @@ public class ThreadLocalRandomTest exten */ public void testNextLongBoundedNeg() { try { - long f = ThreadLocalRandom.current().nextLong(-17); - } catch(IllegalArgumentException success) { - } + long f = ThreadLocalRandom.current().nextLong(-17); + shouldThrow(); + } catch (IllegalArgumentException success) {} } /** @@ -191,9 +188,9 @@ public class ThreadLocalRandomTest exten */ public void testNextLongBadBounds() { try { - long f = ThreadLocalRandom.current().nextLong(17, 2); - } catch(IllegalArgumentException success) { - } + long f = ThreadLocalRandom.current().nextLong(17, 2); + shouldThrow(); + } catch (IllegalArgumentException success) {} } /** @@ -206,7 +203,7 @@ public class ThreadLocalRandomTest exten assertTrue(0 <= f && f < bound); int i = 0; long j; - while (i < NCALLS && + while (i < NCALLS && (j = ThreadLocalRandom.current().nextLong(bound)) == f) { assertTrue(0 <= j && j < bound); ++i; @@ -226,7 +223,7 @@ public class ThreadLocalRandomTest exten assertTrue(least <= f && f < bound); int i = 0; long j; - while (i < NCALLS && + while (i < NCALLS && (j = ThreadLocalRandom.current().nextLong(least, bound)) == f) { assertTrue(least <= j && j < bound); ++i; @@ -236,7 +233,6 @@ public class ThreadLocalRandomTest exten } } - /** * nextDouble(least, bound) returns least <= value < bound; * repeated calls produce at least one different result @@ -248,7 +244,7 @@ public class ThreadLocalRandomTest exten assertTrue(least <= f && f < bound); int i = 0; double j; - while (i < NCALLS && + while (i < NCALLS && (j = ThreadLocalRandom.current().nextDouble(least, bound)) == f) { assertTrue(least <= j && j < bound); ++i; @@ -258,5 +254,40 @@ 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; + + final CheckedRunnable getRandomState = new CheckedRunnable() { + public void realRun() { + ThreadLocalRandom current = ThreadLocalRandom.current(); + assertSame(current, ThreadLocalRandom.current()); + 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"); + } }