test/tck/SplittableRandomTest.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 java.util.Arrays;
import java.util.ArrayList;
import java.util.List;
import java.util.SplittableRandom;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.LongAdder;
import java.lang.reflect.Method;
import java.util.function.Predicate;
import java.util.stream.Collectors;

import junit.framework.Test;
import junit.framework.TestSuite;

public class SplittableRandomTest extends JSR166TestCase {

    public static void main(String[] args) {
        main(suite(), args);
    }
    public static Test suite() {
        return new TestSuite(SplittableRandomTest.class);
    }

    /*
     * Testing coverage notes:
     *
     * 1. Many of the test methods are adapted from ThreadLocalRandomTest.
     *
     * 2. These tests do not check for random number generator quality.
     * But we check for minimal API compliance by requiring that
     * repeated calls to nextX methods, up to NCALLS tries, produce at
     * least two distinct results. (In some possible universe, a
     * "correct" implementation might fail, but the odds are vastly
     * less than that of encountering a hardware failure while running
     * the test.) For bounded nextX methods, we sample various
     * intervals across multiples of primes. In other tests, we repeat
     * under REPS different values.
     */

    // 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 << 26);

    // max sampled long bound
    static final long MAX_LONG_BOUND = (1L << 40);

    // Number of replications for other checks
    static final int REPS =
        Integer.getInteger("SplittableRandomTest.reps", 4);

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

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

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

    /**
     * Two SplittableRandoms created with the same seed produce the
     * same values for nextLong.
     */
    public void testSeedConstructor() {
        for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
            SplittableRandom sr1 = new SplittableRandom(seed);
            SplittableRandom sr2 = new SplittableRandom(seed);
            for (int i = 0; i < REPS; ++i)
                assertEquals(sr1.nextLong(), sr2.nextLong());
        }
    }

    /**
     * A SplittableRandom produced by split() of a default-constructed
     * SplittableRandom generates a different sequence
     */
    public void testSplit1() {
        SplittableRandom sr = new SplittableRandom();
        for (int reps = 0; reps < REPS; ++reps) {
            SplittableRandom sc = sr.split();
            int i = 0;
            while (i < NCALLS && sr.nextLong() == sc.nextLong())
                ++i;
            assertTrue(i < NCALLS);
        }
    }

    /**
     * A SplittableRandom produced by split() of a seeded-constructed
     * SplittableRandom generates a different sequence
     */
    public void testSplit2() {
        SplittableRandom sr = new SplittableRandom(12345);
        for (int reps = 0; reps < REPS; ++reps) {
            SplittableRandom sc = sr.split();
            int i = 0;
            while (i < NCALLS && sr.nextLong() == sc.nextLong())
                ++i;
            assertTrue(i < NCALLS);
        }
    }

    /**
     * nextInt(non-positive) throws IllegalArgumentException
     */
    public void testNextIntBoundNonPositive() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextInt(-17),
            () -> sr.nextInt(0),
            () -> sr.nextInt(Integer.MIN_VALUE),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * nextInt(least >= bound) throws IllegalArgumentException
     */
    public void testNextIntBadBounds() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextInt(17, 2),
            () -> sr.nextInt(-42, -42),
            () -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * nextInt(bound) returns 0 <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextIntBounded() {
        SplittableRandom sr = new SplittableRandom();
        for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
        // sample bound space across prime number increments
        for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
            int f = sr.nextInt(bound);
            assertTrue(0 <= f && f < bound);
            int i = 0;
            int j;
            while (i < NCALLS &&
                   (j = sr.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() {
        SplittableRandom sr = new SplittableRandom();
        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 = sr.nextInt(least, bound);
                assertTrue(least <= f && f < bound);
                int i = 0;
                int j;
                while (i < NCALLS &&
                       (j = sr.nextInt(least, bound)) == f) {
                    assertTrue(least <= j && j < bound);
                    ++i;
                }
                assertTrue(i < NCALLS);
            }
        }
    }

    /**
     * nextLong(non-positive) throws IllegalArgumentException
     */
    public void testNextLongBoundNonPositive() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextLong(-17L),
            () -> sr.nextLong(0L),
            () -> sr.nextLong(Long.MIN_VALUE),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * nextLong(least >= bound) throws IllegalArgumentException
     */
    public void testNextLongBadBounds() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextLong(17L, 2L),
            () -> sr.nextLong(-42L, -42L),
            () -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * nextLong(bound) returns 0 <= value < bound;
     * repeated calls produce at least two distinct results
     */
    public void testNextLongBounded() {
        SplittableRandom sr = new SplittableRandom();
        for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
        for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
            long f = sr.nextLong(bound);
            assertTrue(0 <= f && f < bound);
            int i = 0;
            long j;
            while (i < NCALLS &&
                   (j = sr.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() {
        SplittableRandom sr = new SplittableRandom();
        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 = sr.nextLong(least, bound);
                assertTrue(least <= f && f < bound);
                int i = 0;
                long j;
                while (i < NCALLS &&
                       (j = sr.nextLong(least, bound)) == f) {
                    assertTrue(least <= j && j < bound);
                    ++i;
                }
                assertTrue(i < NCALLS);
            }
        }
    }

    /**
     * nextDouble(non-positive) throws IllegalArgumentException
     */
    public void testNextDoubleBoundNonPositive() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextDouble(-17.0d),
            () -> sr.nextDouble(0.0d),
            () -> sr.nextDouble(-Double.MIN_VALUE),
            () -> sr.nextDouble(Double.NEGATIVE_INFINITY),
            () -> sr.nextDouble(Double.NaN),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * nextDouble(! (least < bound)) throws IllegalArgumentException
     */
    public void testNextDoubleBadBounds() {
        SplittableRandom sr = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> sr.nextDouble(17.0d, 2.0d),
            () -> sr.nextDouble(-42.0d, -42.0d),
            () -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
            () -> sr.nextDouble(Double.NaN, 0.0d),
            () -> sr.nextDouble(0.0d, Double.NaN),
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    // TODO: Test infinite bounds!
    //() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
    //() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),

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

    /**
     * Invoking sized ints, long, doubles, with negative sizes throws
     * IllegalArgumentException
     */
    public void testBadStreamSize() {
        SplittableRandom r = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> { java.util.stream.IntStream x = r.ints(-1L); },
            () -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
            () -> { java.util.stream.LongStream x = r.longs(-1L); },
            () -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
            () -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
            () -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * Invoking bounded ints, long, doubles, with illegal bounds throws
     * IllegalArgumentException
     */
    public void testBadStreamBounds() {
        SplittableRandom r = new SplittableRandom();
        Runnable[] throwingActions = {
            () -> { java.util.stream.IntStream x = r.ints(2, 1); },
            () -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
            () -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
            () -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
            () -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
            () -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
        };
        assertThrows(IllegalArgumentException.class, throwingActions);
    }

    /**
     * A parallel sized stream of ints generates the given number of values
     */
    public void testIntsCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 0;
        for (int reps = 0; reps < REPS; ++reps) {
            counter.reset();
            r.ints(size).parallel().forEach(x -> counter.increment());
            assertEquals(size, counter.sum());
            size += 524959;
        }
    }

    /**
     * A parallel sized stream of longs generates the given number of values
     */
    public void testLongsCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 0;
        for (int reps = 0; reps < REPS; ++reps) {
            counter.reset();
            r.longs(size).parallel().forEach(x -> counter.increment());
            assertEquals(size, counter.sum());
            size += 524959;
        }
    }

    /**
     * A parallel sized stream of doubles generates the given number of values
     */
    public void testDoublesCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 0;
        for (int reps = 0; reps < REPS; ++reps) {
            counter.reset();
            r.doubles(size).parallel().forEach(x -> counter.increment());
            assertEquals(size, counter.sum());
            size += 524959;
        }
    }

    /**
     * Each of a parallel sized stream of bounded ints is within bounds
     */
    public void testBoundedInts() {
        AtomicInteger fails = new AtomicInteger(0);
        SplittableRandom r = new SplittableRandom();
        long size = 12345L;
        for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
            for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
                final int lo = least, hi = bound;
                r.ints(size, lo, hi).parallel().forEach(
                    x -> {
                        if (x < lo || x >= hi)
                            fails.getAndIncrement(); });
            }
        }
        assertEquals(0, fails.get());
    }

    /**
     * Each of a parallel sized stream of bounded longs is within bounds
     */
    public void testBoundedLongs() {
        AtomicInteger fails = new AtomicInteger(0);
        SplittableRandom r = new SplittableRandom();
        long size = 123L;
        for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
            for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
                final long lo = least, hi = bound;
                r.longs(size, lo, hi).parallel().forEach(
                    x -> {
                        if (x < lo || x >= hi)
                            fails.getAndIncrement(); });
            }
        }
        assertEquals(0, fails.get());
    }

    /**
     * Each of a parallel sized stream of bounded doubles is within bounds
     */
    public void testBoundedDoubles() {
        AtomicInteger fails = new AtomicInteger(0);
        SplittableRandom r = new SplittableRandom();
        long size = 456;
        for (double least = 0.00011; least < 1.0e20; least *= 9) {
            for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
                final double lo = least, hi = bound;
                r.doubles(size, lo, hi).parallel().forEach(
                    x -> {
                        if (x < lo || x >= hi)
                            fails.getAndIncrement(); });
            }
        }
        assertEquals(0, fails.get());
    }

    /**
     * A parallel unsized stream of ints generates at least 100 values
     */
    public void testUnsizedIntsCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.ints().limit(size).parallel().forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * A parallel unsized stream of longs generates at least 100 values
     */
    public void testUnsizedLongsCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.longs().limit(size).parallel().forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * A parallel unsized stream of doubles generates at least 100 values
     */
    public void testUnsizedDoublesCount() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.doubles().limit(size).parallel().forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * A sequential unsized stream of ints generates at least 100 values
     */
    public void testUnsizedIntsCountSeq() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.ints().limit(size).forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * A sequential unsized stream of longs generates at least 100 values
     */
    public void testUnsizedLongsCountSeq() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.longs().limit(size).forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * A sequential unsized stream of doubles generates at least 100 values
     */
    public void testUnsizedDoublesCountSeq() {
        LongAdder counter = new LongAdder();
        SplittableRandom r = new SplittableRandom();
        long size = 100;
        r.doubles().limit(size).forEach(x -> counter.increment());
        assertEquals(size, counter.sum());
    }

    /**
     * SplittableRandom should implement most of Random's public methods
     */
    public void testShouldImplementMostRandomMethods() throws Throwable {
        Predicate<Method> wasForgotten = method -> {
            String name = method.getName();
            // some methods deliberately not implemented
            if (name.equals("setSeed")) return false;
            if (name.equals("nextFloat")) return false;
            if (name.equals("nextGaussian")) return false;
            try {
                SplittableRandom.class.getMethod(
                    method.getName(), method.getParameterTypes());
            } catch (ReflectiveOperationException ex) {
                return true;
            }
            return false;
        };
        List<Method> forgotten =
            Arrays.stream(java.util.Random.class.getMethods())
            .filter(wasForgotten)
            .collect(Collectors.toList());
        if (!forgotten.isEmpty())
            throw new AssertionError("Please implement: " + forgotten);
    }

    /**
     * Repeated calls to nextBytes produce at least values of different signs for every byte
     */
    public void testNextBytes() {
        SplittableRandom sr = new SplittableRandom();
        int n = sr.nextInt(20);
        byte[] bytes = new byte[n];
        outer:
        for (int i = 0; i < n; i++) {
            for (int tries = NCALLS; tries-->0; ) {
                byte before = bytes[i];
                sr.nextBytes(bytes);
                byte after = bytes[i];
                if (after * before < 0)
                    continue outer;
            }
            fail("not enough variation in random bytes");
        }
    }

}
Revision:	1.22
Committed:	Tue Oct 3 22:27:04 2017 UTC (6 years, 7 months ago) by jsr166
Branch:	MAIN
Changes since 1.21:	+52 -0 lines
Log Message:	8188047: Add SplittableRandom.nextBytes
#	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			* http://creativecommons.org/publicdomain/zero/1.0/
5			*/
6	jsr166	1.16
7	jsr166	1.22	import java.util.Arrays;
8			import java.util.ArrayList;
9			import java.util.List;
10	dl	1.1	import java.util.SplittableRandom;
11			import java.util.concurrent.atomic.AtomicInteger;
12			import java.util.concurrent.atomic.LongAdder;
13	jsr166	1.22	import java.lang.reflect.Method;
14			import java.util.function.Predicate;
15			import java.util.stream.Collectors;
16	dl	1.1
17	jsr166	1.16	import junit.framework.Test;
18			import junit.framework.TestSuite;
19
20	dl	1.1	public class SplittableRandomTest extends JSR166TestCase {
21
22			public static void main(String[] args) {
23	jsr166	1.18	main(suite(), args);
24	dl	1.1	}
25			public static Test suite() {
26			return new TestSuite(SplittableRandomTest.class);
27			}
28
29			/*
30			* Testing coverage notes:
31			*
32	jsr166	1.4	* 1. Many of the test methods are adapted from ThreadLocalRandomTest.
33	dl	1.1	*
34	jsr166	1.4	* 2. These tests do not check for random number generator quality.
35			* But we check for minimal API compliance by requiring that
36			* repeated calls to nextX methods, up to NCALLS tries, produce at
37			* least two distinct results. (In some possible universe, a
38			* "correct" implementation might fail, but the odds are vastly
39			* less than that of encountering a hardware failure while running
40			* the test.) For bounded nextX methods, we sample various
41			* intervals across multiples of primes. In other tests, we repeat
42			* under REPS different values.
43	dl	1.1	*/
44
45			// max numbers of calls to detect getting stuck on one value
46			static final int NCALLS = 10000;
47
48			// max sampled int bound
49	jsr166	1.11	static final int MAX_INT_BOUND = (1 << 26);
50	dl	1.1
51	jsr166	1.4	// max sampled long bound
52	jsr166	1.12	static final long MAX_LONG_BOUND = (1L << 40);
53	dl	1.1
54			// Number of replications for other checks
55	jsr166	1.7	static final int REPS =
56			Integer.getInteger("SplittableRandomTest.reps", 4);
57	dl	1.1
58			/**
59	jsr166	1.4	* Repeated calls to nextInt produce at least two distinct results
60	dl	1.1	*/
61			public void testNextInt() {
62			SplittableRandom sr = new SplittableRandom();
63			int f = sr.nextInt();
64			int i = 0;
65			while (i < NCALLS && sr.nextInt() == f)
66			++i;
67			assertTrue(i < NCALLS);
68			}
69
70			/**
71	jsr166	1.4	* Repeated calls to nextLong produce at least two distinct results
72	dl	1.1	*/
73			public void testNextLong() {
74			SplittableRandom sr = new SplittableRandom();
75			long f = sr.nextLong();
76			int i = 0;
77			while (i < NCALLS && sr.nextLong() == f)
78			++i;
79			assertTrue(i < NCALLS);
80			}
81
82			/**
83	jsr166	1.4	* Repeated calls to nextDouble produce at least two distinct results
84	dl	1.1	*/
85			public void testNextDouble() {
86			SplittableRandom sr = new SplittableRandom();
87			double f = sr.nextDouble();
88	jsr166	1.4	int i = 0;
89	dl	1.1	while (i < NCALLS && sr.nextDouble() == f)
90			++i;
91			assertTrue(i < NCALLS);
92			}
93
94			/**
95			* Two SplittableRandoms created with the same seed produce the
96			* same values for nextLong.
97			*/
98			public void testSeedConstructor() {
99	jsr166	1.14	for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
100	dl	1.1	SplittableRandom sr1 = new SplittableRandom(seed);
101			SplittableRandom sr2 = new SplittableRandom(seed);
102	jsr166	1.3	for (int i = 0; i < REPS; ++i)
103	dl	1.1	assertEquals(sr1.nextLong(), sr2.nextLong());
104			}
105			}
106
107			/**
108			* A SplittableRandom produced by split() of a default-constructed
109			* SplittableRandom generates a different sequence
110			*/
111			public void testSplit1() {
112			SplittableRandom sr = new SplittableRandom();
113			for (int reps = 0; reps < REPS; ++reps) {
114			SplittableRandom sc = sr.split();
115			int i = 0;
116			while (i < NCALLS && sr.nextLong() == sc.nextLong())
117			++i;
118			assertTrue(i < NCALLS);
119			}
120			}
121
122			/**
123			* A SplittableRandom produced by split() of a seeded-constructed
124			* SplittableRandom generates a different sequence
125			*/
126			public void testSplit2() {
127			SplittableRandom sr = new SplittableRandom(12345);
128			for (int reps = 0; reps < REPS; ++reps) {
129			SplittableRandom sc = sr.split();
130			int i = 0;
131			while (i < NCALLS && sr.nextLong() == sc.nextLong())
132			++i;
133			assertTrue(i < NCALLS);
134			}
135			}
136
137			/**
138	jsr166	1.9	* nextInt(non-positive) throws IllegalArgumentException
139	dl	1.1	*/
140	jsr166	1.13	public void testNextIntBoundNonPositive() {
141	dl	1.1	SplittableRandom sr = new SplittableRandom();
142	jsr166	1.9	Runnable[] throwingActions = {
143			() -> sr.nextInt(-17),
144			() -> sr.nextInt(0),
145			() -> sr.nextInt(Integer.MIN_VALUE),
146			};
147			assertThrows(IllegalArgumentException.class, throwingActions);
148	dl	1.1	}
149
150			/**
151	jsr166	1.4	* nextInt(least >= bound) throws IllegalArgumentException
152	dl	1.1	*/
153			public void testNextIntBadBounds() {
154			SplittableRandom sr = new SplittableRandom();
155	jsr166	1.10	Runnable[] throwingActions = {
156			() -> sr.nextInt(17, 2),
157			() -> sr.nextInt(-42, -42),
158			() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),
159			};
160			assertThrows(IllegalArgumentException.class, throwingActions);
161	dl	1.1	}
162
163			/**
164			* nextInt(bound) returns 0 <= value < bound;
165	jsr166	1.4	* repeated calls produce at least two distinct results
166	dl	1.1	*/
167			public void testNextIntBounded() {
168			SplittableRandom sr = new SplittableRandom();
169	jsr166	1.19	for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
170	dl	1.1	// sample bound space across prime number increments
171			for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
172			int f = sr.nextInt(bound);
173			assertTrue(0 <= f && f < bound);
174			int i = 0;
175			int j;
176			while (i < NCALLS &&
177			(j = sr.nextInt(bound)) == f) {
178			assertTrue(0 <= j && j < bound);
179			++i;
180			}
181			assertTrue(i < NCALLS);
182			}
183			}
184
185			/**
186			* nextInt(least, bound) returns least <= value < bound;
187	jsr166	1.4	* repeated calls produce at least two distinct results
188	dl	1.1	*/
189			public void testNextIntBounded2() {
190			SplittableRandom sr = new SplittableRandom();
191			for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
192			for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
193			int f = sr.nextInt(least, bound);
194			assertTrue(least <= f && f < bound);
195			int i = 0;
196			int j;
197			while (i < NCALLS &&
198			(j = sr.nextInt(least, bound)) == f) {
199			assertTrue(least <= j && j < bound);
200			++i;
201			}
202			assertTrue(i < NCALLS);
203			}
204			}
205			}
206
207			/**
208	jsr166	1.9	* nextLong(non-positive) throws IllegalArgumentException
209	dl	1.1	*/
210	jsr166	1.13	public void testNextLongBoundNonPositive() {
211	dl	1.1	SplittableRandom sr = new SplittableRandom();
212	jsr166	1.9	Runnable[] throwingActions = {
213			() -> sr.nextLong(-17L),
214			() -> sr.nextLong(0L),
215			() -> sr.nextLong(Long.MIN_VALUE),
216			};
217			assertThrows(IllegalArgumentException.class, throwingActions);
218	dl	1.1	}
219
220			/**
221	jsr166	1.4	* nextLong(least >= bound) throws IllegalArgumentException
222	dl	1.1	*/
223			public void testNextLongBadBounds() {
224			SplittableRandom sr = new SplittableRandom();
225	jsr166	1.10	Runnable[] throwingActions = {
226			() -> sr.nextLong(17L, 2L),
227			() -> sr.nextLong(-42L, -42L),
228			() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),
229			};
230			assertThrows(IllegalArgumentException.class, throwingActions);
231	dl	1.1	}
232
233			/**
234			* nextLong(bound) returns 0 <= value < bound;
235	jsr166	1.4	* repeated calls produce at least two distinct results
236	dl	1.1	*/
237			public void testNextLongBounded() {
238			SplittableRandom sr = new SplittableRandom();
239	jsr166	1.19	for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
240	dl	1.1	for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
241			long f = sr.nextLong(bound);
242			assertTrue(0 <= f && f < bound);
243			int i = 0;
244			long j;
245			while (i < NCALLS &&
246			(j = sr.nextLong(bound)) == f) {
247			assertTrue(0 <= j && j < bound);
248			++i;
249			}
250			assertTrue(i < NCALLS);
251			}
252			}
253
254			/**
255			* nextLong(least, bound) returns least <= value < bound;
256	jsr166	1.4	* repeated calls produce at least two distinct results
257	dl	1.1	*/
258			public void testNextLongBounded2() {
259			SplittableRandom sr = new SplittableRandom();
260			for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
261			for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
262			long f = sr.nextLong(least, bound);
263			assertTrue(least <= f && f < bound);
264			int i = 0;
265			long j;
266			while (i < NCALLS &&
267			(j = sr.nextLong(least, bound)) == f) {
268			assertTrue(least <= j && j < bound);
269			++i;
270			}
271			assertTrue(i < NCALLS);
272			}
273			}
274			}
275
276			/**
277	jsr166	1.9	* nextDouble(non-positive) throws IllegalArgumentException
278			*/
279	jsr166	1.13	public void testNextDoubleBoundNonPositive() {
280	jsr166	1.9	SplittableRandom sr = new SplittableRandom();
281			Runnable[] throwingActions = {
282			() -> sr.nextDouble(-17.0d),
283			() -> sr.nextDouble(0.0d),
284			() -> sr.nextDouble(-Double.MIN_VALUE),
285			() -> sr.nextDouble(Double.NEGATIVE_INFINITY),
286			() -> sr.nextDouble(Double.NaN),
287			};
288			assertThrows(IllegalArgumentException.class, throwingActions);
289			}
290
291			/**
292	jsr166	1.10	* nextDouble(! (least < bound)) throws IllegalArgumentException
293			*/
294			public void testNextDoubleBadBounds() {
295			SplittableRandom sr = new SplittableRandom();
296			Runnable[] throwingActions = {
297			() -> sr.nextDouble(17.0d, 2.0d),
298			() -> sr.nextDouble(-42.0d, -42.0d),
299			() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
300			() -> sr.nextDouble(Double.NaN, 0.0d),
301			() -> sr.nextDouble(0.0d, Double.NaN),
302			};
303			assertThrows(IllegalArgumentException.class, throwingActions);
304			}
305
306			// TODO: Test infinite bounds!
307			//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
308			//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),
309
310			/**
311	dl	1.1	* nextDouble(least, bound) returns least <= value < bound;
312	jsr166	1.4	* repeated calls produce at least two distinct results
313	dl	1.1	*/
314			public void testNextDoubleBounded2() {
315			SplittableRandom sr = new SplittableRandom();
316			for (double least = 0.0001; least < 1.0e20; least *= 8) {
317			for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
318			double f = sr.nextDouble(least, bound);
319			assertTrue(least <= f && f < bound);
320			int i = 0;
321			double j;
322			while (i < NCALLS &&
323			(j = sr.nextDouble(least, bound)) == f) {
324			assertTrue(least <= j && j < bound);
325			++i;
326			}
327			assertTrue(i < NCALLS);
328			}
329			}
330			}
331
332			/**
333			* Invoking sized ints, long, doubles, with negative sizes throws
334			* IllegalArgumentException
335			*/
336			public void testBadStreamSize() {
337			SplittableRandom r = new SplittableRandom();
338	jsr166	1.8	Runnable[] throwingActions = {
339			() -> { java.util.stream.IntStream x = r.ints(-1L); },
340			() -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
341			() -> { java.util.stream.LongStream x = r.longs(-1L); },
342			() -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
343			() -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
344			() -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
345			};
346			assertThrows(IllegalArgumentException.class, throwingActions);
347	dl	1.1	}
348
349			/**
350			* Invoking bounded ints, long, doubles, with illegal bounds throws
351			* IllegalArgumentException
352			*/
353			public void testBadStreamBounds() {
354			SplittableRandom r = new SplittableRandom();
355	jsr166	1.8	Runnable[] throwingActions = {
356			() -> { java.util.stream.IntStream x = r.ints(2, 1); },
357			() -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
358			() -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
359			() -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
360			() -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
361			() -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
362			};
363			assertThrows(IllegalArgumentException.class, throwingActions);
364	dl	1.1	}
365
366			/**
367			* A parallel sized stream of ints generates the given number of values
368			*/
369			public void testIntsCount() {
370			LongAdder counter = new LongAdder();
371			SplittableRandom r = new SplittableRandom();
372			long size = 0;
373			for (int reps = 0; reps < REPS; ++reps) {
374			counter.reset();
375	jsr166	1.6	r.ints(size).parallel().forEach(x -> counter.increment());
376	jsr166	1.4	assertEquals(size, counter.sum());
377	dl	1.1	size += 524959;
378			}
379			}
380
381			/**
382			* A parallel sized stream of longs generates the given number of values
383			*/
384			public void testLongsCount() {
385			LongAdder counter = new LongAdder();
386			SplittableRandom r = new SplittableRandom();
387			long size = 0;
388			for (int reps = 0; reps < REPS; ++reps) {
389			counter.reset();
390	jsr166	1.6	r.longs(size).parallel().forEach(x -> counter.increment());
391	jsr166	1.4	assertEquals(size, counter.sum());
392	dl	1.1	size += 524959;
393			}
394			}
395
396			/**
397			* A parallel sized stream of doubles generates the given number of values
398			*/
399			public void testDoublesCount() {
400			LongAdder counter = new LongAdder();
401			SplittableRandom r = new SplittableRandom();
402			long size = 0;
403			for (int reps = 0; reps < REPS; ++reps) {
404			counter.reset();
405	jsr166	1.6	r.doubles(size).parallel().forEach(x -> counter.increment());
406	jsr166	1.4	assertEquals(size, counter.sum());
407	dl	1.1	size += 524959;
408			}
409			}
410
411			/**
412			* Each of a parallel sized stream of bounded ints is within bounds
413			*/
414			public void testBoundedInts() {
415			AtomicInteger fails = new AtomicInteger(0);
416			SplittableRandom r = new SplittableRandom();
417			long size = 12345L;
418			for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
419			for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
420			final int lo = least, hi = bound;
421	jsr166	1.17	r.ints(size, lo, hi).parallel().forEach(
422			x -> {
423			if (x < lo \|\| x >= hi)
424			fails.getAndIncrement(); });
425	dl	1.1	}
426			}
427	jsr166	1.4	assertEquals(0, fails.get());
428	dl	1.1	}
429
430			/**
431			* Each of a parallel sized stream of bounded longs is within bounds
432			*/
433			public void testBoundedLongs() {
434			AtomicInteger fails = new AtomicInteger(0);
435			SplittableRandom r = new SplittableRandom();
436			long size = 123L;
437			for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
438			for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
439			final long lo = least, hi = bound;
440	jsr166	1.17	r.longs(size, lo, hi).parallel().forEach(
441			x -> {
442			if (x < lo \|\| x >= hi)
443			fails.getAndIncrement(); });
444	dl	1.1	}
445			}
446	jsr166	1.4	assertEquals(0, fails.get());
447	dl	1.1	}
448
449			/**
450			* Each of a parallel sized stream of bounded doubles is within bounds
451			*/
452			public void testBoundedDoubles() {
453			AtomicInteger fails = new AtomicInteger(0);
454			SplittableRandom r = new SplittableRandom();
455			long size = 456;
456			for (double least = 0.00011; least < 1.0e20; least *= 9) {
457			for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
458			final double lo = least, hi = bound;
459	jsr166	1.17	r.doubles(size, lo, hi).parallel().forEach(
460			x -> {
461			if (x < lo \|\| x >= hi)
462			fails.getAndIncrement(); });
463	dl	1.1	}
464			}
465	jsr166	1.4	assertEquals(0, fails.get());
466	dl	1.1	}
467
468	dl	1.2	/**
469			* A parallel unsized stream of ints generates at least 100 values
470			*/
471			public void testUnsizedIntsCount() {
472			LongAdder counter = new LongAdder();
473			SplittableRandom r = new SplittableRandom();
474			long size = 100;
475	jsr166	1.6	r.ints().limit(size).parallel().forEach(x -> counter.increment());
476	jsr166	1.4	assertEquals(size, counter.sum());
477	dl	1.2	}
478
479			/**
480			* A parallel unsized stream of longs generates at least 100 values
481			*/
482			public void testUnsizedLongsCount() {
483			LongAdder counter = new LongAdder();
484			SplittableRandom r = new SplittableRandom();
485			long size = 100;
486	jsr166	1.6	r.longs().limit(size).parallel().forEach(x -> counter.increment());
487	jsr166	1.4	assertEquals(size, counter.sum());
488	dl	1.2	}
489
490			/**
491			* A parallel unsized stream of doubles generates at least 100 values
492			*/
493			public void testUnsizedDoublesCount() {
494			LongAdder counter = new LongAdder();
495			SplittableRandom r = new SplittableRandom();
496			long size = 100;
497	jsr166	1.6	r.doubles().limit(size).parallel().forEach(x -> counter.increment());
498	jsr166	1.4	assertEquals(size, counter.sum());
499	dl	1.2	}
500
501			/**
502			* A sequential unsized stream of ints generates at least 100 values
503			*/
504			public void testUnsizedIntsCountSeq() {
505			LongAdder counter = new LongAdder();
506			SplittableRandom r = new SplittableRandom();
507			long size = 100;
508	jsr166	1.6	r.ints().limit(size).forEach(x -> counter.increment());
509	jsr166	1.4	assertEquals(size, counter.sum());
510	dl	1.2	}
511
512			/**
513			* A sequential unsized stream of longs generates at least 100 values
514			*/
515			public void testUnsizedLongsCountSeq() {
516			LongAdder counter = new LongAdder();
517			SplittableRandom r = new SplittableRandom();
518			long size = 100;
519	jsr166	1.6	r.longs().limit(size).forEach(x -> counter.increment());
520	jsr166	1.4	assertEquals(size, counter.sum());
521	dl	1.2	}
522
523			/**
524			* A sequential unsized stream of doubles generates at least 100 values
525			*/
526			public void testUnsizedDoublesCountSeq() {
527			LongAdder counter = new LongAdder();
528			SplittableRandom r = new SplittableRandom();
529			long size = 100;
530	jsr166	1.6	r.doubles().limit(size).forEach(x -> counter.increment());
531	jsr166	1.4	assertEquals(size, counter.sum());
532	dl	1.2	}
533
534	jsr166	1.22	/**
535			* SplittableRandom should implement most of Random's public methods
536			*/
537			public void testShouldImplementMostRandomMethods() throws Throwable {
538			Predicate<Method> wasForgotten = method -> {
539			String name = method.getName();
540			// some methods deliberately not implemented
541			if (name.equals("setSeed")) return false;
542			if (name.equals("nextFloat")) return false;
543			if (name.equals("nextGaussian")) return false;
544			try {
545			SplittableRandom.class.getMethod(
546			method.getName(), method.getParameterTypes());
547			} catch (ReflectiveOperationException ex) {
548			return true;
549			}
550			return false;
551			};
552			List<Method> forgotten =
553			Arrays.stream(java.util.Random.class.getMethods())
554			.filter(wasForgotten)
555			.collect(Collectors.toList());
556			if (!forgotten.isEmpty())
557			throw new AssertionError("Please implement: " + forgotten);
558			}
559
560			/**
561			* Repeated calls to nextBytes produce at least values of different signs for every byte
562			*/
563			public void testNextBytes() {
564			SplittableRandom sr = new SplittableRandom();
565			int n = sr.nextInt(20);
566			byte[] bytes = new byte[n];
567			outer:
568			for (int i = 0; i < n; i++) {
569			for (int tries = NCALLS; tries-->0; ) {
570			byte before = bytes[i];
571			sr.nextBytes(bytes);
572			byte after = bytes[i];
573			if (after * before < 0)
574			continue outer;
575			}
576			fail("not enough variation in random bytes");
577			}
578			}
579
580	dl	1.1	}