test/tck/ThreadLocalRandomTest.java

/*
 * 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/publicdomain/zero/1.0/
 */
import junit.framework.*;
import java.util.*;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

public class ThreadLocalRandomTest extends JSR166TestCase {

    public static void main(String[] args) {
        junit.textui.TestRunner.run(suite());
    }
    public static Test suite() {
        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.
     */

    // 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
    static final long MAX_LONG_BOUND = (1L << 42);

    // Number of replications for other checks
    static final int REPS = 20;

    /**
     * setSeed throws UnsupportedOperationException
     */
    public void testSetSeed() {
        try {
            ThreadLocalRandom.current().setSeed(17);
            shouldThrow();
        } catch (UnsupportedOperationException success) {}
    }

    /**
     * Repeated calls to nextInt produce at least two distinct results
     */
    public void testNextInt() {
        int f = ThreadLocalRandom.current().nextInt();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextInt() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * Repeated calls to nextLong produce at least two distinct results
     */
    public void testNextLong() {
        long f = ThreadLocalRandom.current().nextLong();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextLong() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * Repeated calls to nextBoolean produce at least two distinct results
     */
    public void testNextBoolean() {
        boolean f = ThreadLocalRandom.current().nextBoolean();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextBoolean() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * Repeated calls to nextFloat produce at least two distinct results
     */
    public void testNextFloat() {
        float f = ThreadLocalRandom.current().nextFloat();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextFloat() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * Repeated calls to nextDouble produce at least two distinct results
     */
    public void testNextDouble() {
        double f = ThreadLocalRandom.current().nextDouble();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextDouble() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * Repeated calls to nextGaussian produce at least two distinct results
     */
    public void testNextGaussian() {
        double f = ThreadLocalRandom.current().nextGaussian();
        int i = 0;
        while (i < NCALLS && ThreadLocalRandom.current().nextGaussian() == f)
            ++i;
        assertTrue(i < NCALLS);
    }

    /**
     * nextInt(negative) throws IllegalArgumentException
     */
    public void testNextIntBoundedNeg() {
        try {
            int f = ThreadLocalRandom.current().nextInt(-17);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * nextInt(least >= bound) throws IllegalArgumentException
     */
    public void testNextIntBadBounds() {
        try {
            int f = ThreadLocalRandom.current().nextInt(17, 2);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * nextInt(bound) returns 0 <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextIntBounded() {
        // sample bound space across prime number increments
        for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
            int f = ThreadLocalRandom.current().nextInt(bound);
            assertTrue(0 <= f && f < bound);
            int i = 0;
            int j;
            while (i < NCALLS &&
                   (j = ThreadLocalRandom.current().nextInt(bound)) == f) {
                assertTrue(0 <= j && j < bound);
                ++i;
            }
            assertTrue(i < NCALLS);
        }
    }

    /**
     * nextInt(least, bound) returns least <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextIntBounded2() {
        for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
            for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
                int f = ThreadLocalRandom.current().nextInt(least, bound);
                assertTrue(least <= f && f < bound);
                int i = 0;
                int j;
                while (i < NCALLS &&
                       (j = ThreadLocalRandom.current().nextInt(least, bound)) == f) {
                    assertTrue(least <= j && j < bound);
                    ++i;
                }
                assertTrue(i < NCALLS);
            }
        }
    }

    /**
     * nextLong(negative) throws IllegalArgumentException
     */
    public void testNextLongBoundedNeg() {
        try {
            long f = ThreadLocalRandom.current().nextLong(-17);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * nextLong(least >= bound) throws IllegalArgumentException
     */
    public void testNextLongBadBounds() {
        try {
            long f = ThreadLocalRandom.current().nextLong(17, 2);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * nextLong(bound) returns 0 <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextLongBounded() {
        for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
            long f = ThreadLocalRandom.current().nextLong(bound);
            assertTrue(0 <= f && f < bound);
            int i = 0;
            long j;
            while (i < NCALLS &&
                   (j = ThreadLocalRandom.current().nextLong(bound)) == f) {
                assertTrue(0 <= j && j < bound);
                ++i;
            }
            assertTrue(i < NCALLS);
        }
    }

    /**
     * nextLong(least, bound) returns least <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextLongBounded2() {
        for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
            for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
                long f = ThreadLocalRandom.current().nextLong(least, bound);
                assertTrue(least <= f && f < bound);
                int i = 0;
                long j;
                while (i < NCALLS &&
                       (j = ThreadLocalRandom.current().nextLong(least, bound)) == f) {
                    assertTrue(least <= j && j < bound);
                    ++i;
                }
                assertTrue(i < NCALLS);
            }
        }
    }

    /**
     * nextDouble(least, bound) returns least <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextDoubleBounded2() {
        for (double least = 0.0001; least < 1.0e20; least *= 8) {
            for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
                double f = ThreadLocalRandom.current().nextDouble(least, bound);
                assertTrue(least <= f && f < bound);
                int i = 0;
                double j;
                while (i < NCALLS &&
                       (j = ThreadLocalRandom.current().nextDouble(least, bound)) == f) {
                    assertTrue(least <= j && j < bound);
                    ++i;
                }
                assertTrue(i < NCALLS);
            }
        }
    }

    /**
     * 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> threadLocalRandom =
            new AtomicReference<ThreadLocalRandom>();
        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());
                // 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");
    }

}
Revision:	1.16
Committed:	Fri Aug 16 07:07:01 2013 UTC (10 years, 9 months ago) by jsr166
Branch:	MAIN
Changes since 1.15:	+0 -230 lines
Log Message:	introduce ThreadLocalRandom8Test, fixing 4jdk7-test-tck
#	User	Rev	Content
1	dl	1.1	/*
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	jsr166	1.8	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.1	*/
6			import junit.framework.*;
7			import java.util.*;
8	jsr166	1.10	import java.util.concurrent.ThreadLocalRandom;
9	jsr166	1.11	import java.util.concurrent.atomic.AtomicLong;
10	dl	1.15	import java.util.concurrent.atomic.AtomicInteger;
11	jsr166	1.11	import java.util.concurrent.atomic.AtomicReference;
12	dl	1.1
13			public class ThreadLocalRandomTest extends JSR166TestCase {
14
15			public static void main(String[] args) {
16	jsr166	1.7	junit.textui.TestRunner.run(suite());
17	dl	1.1	}
18			public static Test suite() {
19	jsr166	1.4	return new TestSuite(ThreadLocalRandomTest.class);
20	dl	1.1	}
21
22	jsr166	1.13	/*
23	dl	1.1	* Testing coverage notes:
24	jsr166	1.2	*
25	dl	1.1	* We don't test randomness properties, but only that repeated
26			* calls, up to NCALLS tries, produce at least one different
27			* result. For bounded versions, we sample various intervals
28			* across multiples of primes.
29			*/
30
31	jsr166	1.14	// max numbers of calls to detect getting stuck on one value
32	dl	1.1	static final int NCALLS = 10000;
33
34			// max sampled int bound
35			static final int MAX_INT_BOUND = (1 << 28);
36
37	jsr166	1.14	// max sampled long bound
38	dl	1.1	static final long MAX_LONG_BOUND = (1L << 42);
39
40	dl	1.15	// Number of replications for other checks
41			static final int REPS = 20;
42
43	dl	1.1	/**
44			* setSeed throws UnsupportedOperationException
45			*/
46			public void testSetSeed() {
47			try {
48			ThreadLocalRandom.current().setSeed(17);
49	jsr166	1.3	shouldThrow();
50	jsr166	1.5	} catch (UnsupportedOperationException success) {}
51	dl	1.1	}
52
53			/**
54	jsr166	1.14	* Repeated calls to nextInt produce at least two distinct results
55	dl	1.1	*/
56			public void testNextInt() {
57			int f = ThreadLocalRandom.current().nextInt();
58			int i = 0;
59			while (i < NCALLS && ThreadLocalRandom.current().nextInt() == f)
60			++i;
61			assertTrue(i < NCALLS);
62			}
63
64			/**
65	jsr166	1.14	* Repeated calls to nextLong produce at least two distinct results
66	dl	1.1	*/
67			public void testNextLong() {
68			long f = ThreadLocalRandom.current().nextLong();
69			int i = 0;
70			while (i < NCALLS && ThreadLocalRandom.current().nextLong() == f)
71			++i;
72			assertTrue(i < NCALLS);
73			}
74
75			/**
76	jsr166	1.14	* Repeated calls to nextBoolean produce at least two distinct results
77	dl	1.1	*/
78			public void testNextBoolean() {
79			boolean f = ThreadLocalRandom.current().nextBoolean();
80			int i = 0;
81			while (i < NCALLS && ThreadLocalRandom.current().nextBoolean() == f)
82			++i;
83			assertTrue(i < NCALLS);
84			}
85
86			/**
87	jsr166	1.14	* Repeated calls to nextFloat produce at least two distinct results
88	dl	1.1	*/
89			public void testNextFloat() {
90			float f = ThreadLocalRandom.current().nextFloat();
91			int i = 0;
92			while (i < NCALLS && ThreadLocalRandom.current().nextFloat() == f)
93			++i;
94			assertTrue(i < NCALLS);
95			}
96
97			/**
98	jsr166	1.14	* Repeated calls to nextDouble produce at least two distinct results
99	dl	1.1	*/
100			public void testNextDouble() {
101			double f = ThreadLocalRandom.current().nextDouble();
102	jsr166	1.14	int i = 0;
103	dl	1.1	while (i < NCALLS && ThreadLocalRandom.current().nextDouble() == f)
104			++i;
105			assertTrue(i < NCALLS);
106			}
107
108			/**
109	jsr166	1.14	* Repeated calls to nextGaussian produce at least two distinct results
110	dl	1.1	*/
111			public void testNextGaussian() {
112			double f = ThreadLocalRandom.current().nextGaussian();
113			int i = 0;
114			while (i < NCALLS && ThreadLocalRandom.current().nextGaussian() == f)
115			++i;
116			assertTrue(i < NCALLS);
117			}
118
119			/**
120	jsr166	1.14	* nextInt(negative) throws IllegalArgumentException
121	dl	1.1	*/
122			public void testNextIntBoundedNeg() {
123			try {
124	jsr166	1.6	int f = ThreadLocalRandom.current().nextInt(-17);
125	jsr166	1.3	shouldThrow();
126	jsr166	1.5	} catch (IllegalArgumentException success) {}
127	dl	1.1	}
128
129			/**
130	jsr166	1.14	* nextInt(least >= bound) throws IllegalArgumentException
131	dl	1.1	*/
132			public void testNextIntBadBounds() {
133			try {
134	jsr166	1.6	int f = ThreadLocalRandom.current().nextInt(17, 2);
135	jsr166	1.3	shouldThrow();
136	jsr166	1.5	} catch (IllegalArgumentException success) {}
137	dl	1.1	}
138
139			/**
140			* nextInt(bound) returns 0 <= value < bound;
141	jsr166	1.14	* repeated calls produce at least two distinct results
142	dl	1.1	*/
143			public void testNextIntBounded() {
144			// sample bound space across prime number increments
145			for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
146			int f = ThreadLocalRandom.current().nextInt(bound);
147			assertTrue(0 <= f && f < bound);
148			int i = 0;
149			int j;
150	jsr166	1.2	while (i < NCALLS &&
151	dl	1.1	(j = ThreadLocalRandom.current().nextInt(bound)) == f) {
152			assertTrue(0 <= j && j < bound);
153			++i;
154			}
155			assertTrue(i < NCALLS);
156			}
157			}
158
159			/**
160			* nextInt(least, bound) returns least <= value < bound;
161	jsr166	1.14	* repeated calls produce at least two distinct results
162	dl	1.1	*/
163			public void testNextIntBounded2() {
164			for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
165			for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
166			int f = ThreadLocalRandom.current().nextInt(least, bound);
167			assertTrue(least <= f && f < bound);
168			int i = 0;
169			int j;
170	jsr166	1.2	while (i < NCALLS &&
171	dl	1.1	(j = ThreadLocalRandom.current().nextInt(least, bound)) == f) {
172			assertTrue(least <= j && j < bound);
173			++i;
174			}
175			assertTrue(i < NCALLS);
176			}
177			}
178			}
179
180			/**
181	jsr166	1.14	* nextLong(negative) throws IllegalArgumentException
182	dl	1.1	*/
183			public void testNextLongBoundedNeg() {
184			try {
185	jsr166	1.6	long f = ThreadLocalRandom.current().nextLong(-17);
186	jsr166	1.3	shouldThrow();
187	jsr166	1.5	} catch (IllegalArgumentException success) {}
188	dl	1.1	}
189
190			/**
191	jsr166	1.14	* nextLong(least >= bound) throws IllegalArgumentException
192	dl	1.1	*/
193			public void testNextLongBadBounds() {
194			try {
195	jsr166	1.6	long f = ThreadLocalRandom.current().nextLong(17, 2);
196	jsr166	1.3	shouldThrow();
197	jsr166	1.5	} catch (IllegalArgumentException success) {}
198	dl	1.1	}
199
200			/**
201			* nextLong(bound) returns 0 <= value < bound;
202	jsr166	1.14	* repeated calls produce at least two distinct results
203	dl	1.1	*/
204			public void testNextLongBounded() {
205			for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
206			long f = ThreadLocalRandom.current().nextLong(bound);
207			assertTrue(0 <= f && f < bound);
208			int i = 0;
209			long j;
210	jsr166	1.2	while (i < NCALLS &&
211	dl	1.1	(j = ThreadLocalRandom.current().nextLong(bound)) == f) {
212			assertTrue(0 <= j && j < bound);
213			++i;
214			}
215			assertTrue(i < NCALLS);
216			}
217			}
218
219			/**
220			* nextLong(least, bound) returns least <= value < bound;
221	jsr166	1.14	* repeated calls produce at least two distinct results
222	dl	1.1	*/
223			public void testNextLongBounded2() {
224			for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
225			for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
226			long f = ThreadLocalRandom.current().nextLong(least, bound);
227			assertTrue(least <= f && f < bound);
228			int i = 0;
229			long j;
230	jsr166	1.2	while (i < NCALLS &&
231	dl	1.1	(j = ThreadLocalRandom.current().nextLong(least, bound)) == f) {
232			assertTrue(least <= j && j < bound);
233			++i;
234			}
235			assertTrue(i < NCALLS);
236			}
237			}
238			}
239
240			/**
241			* nextDouble(least, bound) returns least <= value < bound;
242	jsr166	1.14	* repeated calls produce at least two distinct results
243	dl	1.1	*/
244			public void testNextDoubleBounded2() {
245			for (double least = 0.0001; least < 1.0e20; least *= 8) {
246			for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
247			double f = ThreadLocalRandom.current().nextDouble(least, bound);
248			assertTrue(least <= f && f < bound);
249			int i = 0;
250			double j;
251	jsr166	1.2	while (i < NCALLS &&
252	dl	1.1	(j = ThreadLocalRandom.current().nextDouble(least, bound)) == f) {
253			assertTrue(least <= j && j < bound);
254			++i;
255			}
256			assertTrue(i < NCALLS);
257			}
258			}
259			}
260
261	jsr166	1.11	/**
262			* Different threads produce different pseudo-random sequences
263			*/
264			public void testDifferentSequences() {
265			// Don't use main thread's ThreadLocalRandom - it is likely to
266			// be polluted by previous tests.
267			final AtomicReference<ThreadLocalRandom> threadLocalRandom =
268			new AtomicReference<ThreadLocalRandom>();
269			final AtomicLong rand = new AtomicLong();
270
271			long firstRand = 0;
272			ThreadLocalRandom firstThreadLocalRandom = null;
273
274			final CheckedRunnable getRandomState = new CheckedRunnable() {
275			public void realRun() {
276			ThreadLocalRandom current = ThreadLocalRandom.current();
277			assertSame(current, ThreadLocalRandom.current());
278	dl	1.12	// test bug: the following is not guaranteed and not true in JDK8
279			// assertNotSame(current, threadLocalRandom.get());
280	jsr166	1.11	rand.set(current.nextLong());
281			threadLocalRandom.set(current);
282			}};
283
284			Thread first = newStartedThread(getRandomState);
285			awaitTermination(first);
286			firstRand = rand.get();
287			firstThreadLocalRandom = threadLocalRandom.get();
288
289			for (int i = 0; i < NCALLS; i++) {
290			Thread t = newStartedThread(getRandomState);
291			awaitTermination(t);
292			if (firstRand != rand.get())
293			return;
294			}
295			fail("all threads generate the same pseudo-random sequence");
296			}
297
298	dl	1.1	}