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.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 java.util.stream.DoubleStream;
import java.util.stream.IntStream;
import java.util.stream.LongStream;

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();
        assertThrows(
            IllegalArgumentException.class,
            () -> sr.nextInt(-17),
            () -> sr.nextInt(0),
            () -> sr.nextInt(Integer.MIN_VALUE));
    }

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

    /**
     * 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();
        assertThrows(
            IllegalArgumentException.class,
            () -> sr.nextLong(-17L),
            () -> sr.nextLong(0L),
            () -> sr.nextLong(Long.MIN_VALUE));
    }

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

    /**
     * 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();
        assertThrows(
            IllegalArgumentException.class,
            () -> sr.nextDouble(-17.0d),
            () -> sr.nextDouble(0.0d),
            () -> sr.nextDouble(-Double.MIN_VALUE),
            () -> sr.nextDouble(Double.NEGATIVE_INFINITY),
            () -> sr.nextDouble(Double.NaN));
    }

    /**
     * nextDouble(! (least < bound)) throws IllegalArgumentException
     */
    public void testNextDoubleBadBounds() {
        SplittableRandom sr = new SplittableRandom();
        assertThrows(
            IllegalArgumentException.class,
            () -> 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));
    }

    // 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();
        assertThrows(
            IllegalArgumentException.class,
            () -> { IntStream unused = r.ints(-1L); },
            () -> { IntStream unused = r.ints(-1L, 2, 3); },
            () -> { LongStream unused = r.longs(-1L); },
            () -> { LongStream unused = r.longs(-1L, -1L, 1L); },
            () -> { DoubleStream unused = r.doubles(-1L); },
            () -> { DoubleStream unused = r.doubles(-1L, .5, .6); });
    }

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

    /**
     * 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(1, 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");
        }
    }

    /**
     * Filling an empty array with random bytes succeeds without effect.
     */
    public void testNextBytes_emptyArray() {
        new SplittableRandom().nextBytes(new byte[0]);
    }

    public void testNextBytes_nullArray() {
        try {
            new SplittableRandom().nextBytes(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

}
Revision:	1.26
Committed:	Mon Dec 16 22:55:54 2019 UTC (4 years, 4 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.25:	+15 -12 lines
Log Message:	fix a few [UnusedVariable] warnings
#	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
7	import java.util.Arrays;
8	import java.util.List;
9	import java.util.SplittableRandom;
10	import java.util.concurrent.atomic.AtomicInteger;
11	import java.util.concurrent.atomic.LongAdder;
12	import java.lang.reflect.Method;
13	import java.util.function.Predicate;
14	import java.util.stream.Collectors;
15	import java.util.stream.DoubleStream;
16	import java.util.stream.IntStream;
17	import java.util.stream.LongStream;
18
19	import junit.framework.Test;
20	import junit.framework.TestSuite;
21
22	public class SplittableRandomTest extends JSR166TestCase {
23
24	public static void main(String[] args) {
25	main(suite(), args);
26	}
27	public static Test suite() {
28	return new TestSuite(SplittableRandomTest.class);
29	}
30
31	/*
32	* Testing coverage notes:
33	*
34	* 1. Many of the test methods are adapted from ThreadLocalRandomTest.
35	*
36	* 2. These tests do not check for random number generator quality.
37	* But we check for minimal API compliance by requiring that
38	* repeated calls to nextX methods, up to NCALLS tries, produce at
39	* least two distinct results. (In some possible universe, a
40	* "correct" implementation might fail, but the odds are vastly
41	* less than that of encountering a hardware failure while running
42	* the test.) For bounded nextX methods, we sample various
43	* intervals across multiples of primes. In other tests, we repeat
44	* under REPS different values.
45	*/
46
47	// max numbers of calls to detect getting stuck on one value
48	static final int NCALLS = 10000;
49
50	// max sampled int bound
51	static final int MAX_INT_BOUND = (1 << 26);
52
53	// max sampled long bound
54	static final long MAX_LONG_BOUND = (1L << 40);
55
56	// Number of replications for other checks
57	static final int REPS =
58	Integer.getInteger("SplittableRandomTest.reps", 4);
59
60	/**
61	* Repeated calls to nextInt produce at least two distinct results
62	*/
63	public void testNextInt() {
64	SplittableRandom sr = new SplittableRandom();
65	int f = sr.nextInt();
66	int i = 0;
67	while (i < NCALLS && sr.nextInt() == f)
68	++i;
69	assertTrue(i < NCALLS);
70	}
71
72	/**
73	* Repeated calls to nextLong produce at least two distinct results
74	*/
75	public void testNextLong() {
76	SplittableRandom sr = new SplittableRandom();
77	long f = sr.nextLong();
78	int i = 0;
79	while (i < NCALLS && sr.nextLong() == f)
80	++i;
81	assertTrue(i < NCALLS);
82	}
83
84	/**
85	* Repeated calls to nextDouble produce at least two distinct results
86	*/
87	public void testNextDouble() {
88	SplittableRandom sr = new SplittableRandom();
89	double f = sr.nextDouble();
90	int i = 0;
91	while (i < NCALLS && sr.nextDouble() == f)
92	++i;
93	assertTrue(i < NCALLS);
94	}
95
96	/**
97	* Two SplittableRandoms created with the same seed produce the
98	* same values for nextLong.
99	*/
100	public void testSeedConstructor() {
101	for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
102	SplittableRandom sr1 = new SplittableRandom(seed);
103	SplittableRandom sr2 = new SplittableRandom(seed);
104	for (int i = 0; i < REPS; ++i)
105	assertEquals(sr1.nextLong(), sr2.nextLong());
106	}
107	}
108
109	/**
110	* A SplittableRandom produced by split() of a default-constructed
111	* SplittableRandom generates a different sequence
112	*/
113	public void testSplit1() {
114	SplittableRandom sr = new SplittableRandom();
115	for (int reps = 0; reps < REPS; ++reps) {
116	SplittableRandom sc = sr.split();
117	int i = 0;
118	while (i < NCALLS && sr.nextLong() == sc.nextLong())
119	++i;
120	assertTrue(i < NCALLS);
121	}
122	}
123
124	/**
125	* A SplittableRandom produced by split() of a seeded-constructed
126	* SplittableRandom generates a different sequence
127	*/
128	public void testSplit2() {
129	SplittableRandom sr = new SplittableRandom(12345);
130	for (int reps = 0; reps < REPS; ++reps) {
131	SplittableRandom sc = sr.split();
132	int i = 0;
133	while (i < NCALLS && sr.nextLong() == sc.nextLong())
134	++i;
135	assertTrue(i < NCALLS);
136	}
137	}
138
139	/**
140	* nextInt(non-positive) throws IllegalArgumentException
141	*/
142	public void testNextIntBoundNonPositive() {
143	SplittableRandom sr = new SplittableRandom();
144	assertThrows(
145	IllegalArgumentException.class,
146	() -> sr.nextInt(-17),
147	() -> sr.nextInt(0),
148	() -> sr.nextInt(Integer.MIN_VALUE));
149	}
150
151	/**
152	* nextInt(least >= bound) throws IllegalArgumentException
153	*/
154	public void testNextIntBadBounds() {
155	SplittableRandom sr = new SplittableRandom();
156	assertThrows(
157	IllegalArgumentException.class,
158	() -> sr.nextInt(17, 2),
159	() -> sr.nextInt(-42, -42),
160	() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE));
161	}
162
163	/**
164	* nextInt(bound) returns 0 <= value < bound;
165	* repeated calls produce at least two distinct results
166	*/
167	public void testNextIntBounded() {
168	SplittableRandom sr = new SplittableRandom();
169	for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
170	// 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	* repeated calls produce at least two distinct results
188	*/
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	* nextLong(non-positive) throws IllegalArgumentException
209	*/
210	public void testNextLongBoundNonPositive() {
211	SplittableRandom sr = new SplittableRandom();
212	assertThrows(
213	IllegalArgumentException.class,
214	() -> sr.nextLong(-17L),
215	() -> sr.nextLong(0L),
216	() -> sr.nextLong(Long.MIN_VALUE));
217	}
218
219	/**
220	* nextLong(least >= bound) throws IllegalArgumentException
221	*/
222	public void testNextLongBadBounds() {
223	SplittableRandom sr = new SplittableRandom();
224	assertThrows(
225	IllegalArgumentException.class,
226	() -> sr.nextLong(17L, 2L),
227	() -> sr.nextLong(-42L, -42L),
228	() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE));
229	}
230
231	/**
232	* nextLong(bound) returns 0 <= value < bound;
233	* repeated calls produce at least two distinct results
234	*/
235	public void testNextLongBounded() {
236	SplittableRandom sr = new SplittableRandom();
237	for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
238	for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
239	long f = sr.nextLong(bound);
240	assertTrue(0 <= f && f < bound);
241	int i = 0;
242	long j;
243	while (i < NCALLS &&
244	(j = sr.nextLong(bound)) == f) {
245	assertTrue(0 <= j && j < bound);
246	++i;
247	}
248	assertTrue(i < NCALLS);
249	}
250	}
251
252	/**
253	* nextLong(least, bound) returns least <= value < bound;
254	* repeated calls produce at least two distinct results
255	*/
256	public void testNextLongBounded2() {
257	SplittableRandom sr = new SplittableRandom();
258	for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
259	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
260	long f = sr.nextLong(least, bound);
261	assertTrue(least <= f && f < bound);
262	int i = 0;
263	long j;
264	while (i < NCALLS &&
265	(j = sr.nextLong(least, bound)) == f) {
266	assertTrue(least <= j && j < bound);
267	++i;
268	}
269	assertTrue(i < NCALLS);
270	}
271	}
272	}
273
274	/**
275	* nextDouble(non-positive) throws IllegalArgumentException
276	*/
277	public void testNextDoubleBoundNonPositive() {
278	SplittableRandom sr = new SplittableRandom();
279	assertThrows(
280	IllegalArgumentException.class,
281	() -> sr.nextDouble(-17.0d),
282	() -> sr.nextDouble(0.0d),
283	() -> sr.nextDouble(-Double.MIN_VALUE),
284	() -> sr.nextDouble(Double.NEGATIVE_INFINITY),
285	() -> sr.nextDouble(Double.NaN));
286	}
287
288	/**
289	* nextDouble(! (least < bound)) throws IllegalArgumentException
290	*/
291	public void testNextDoubleBadBounds() {
292	SplittableRandom sr = new SplittableRandom();
293	assertThrows(
294	IllegalArgumentException.class,
295	() -> sr.nextDouble(17.0d, 2.0d),
296	() -> sr.nextDouble(-42.0d, -42.0d),
297	() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
298	() -> sr.nextDouble(Double.NaN, 0.0d),
299	() -> sr.nextDouble(0.0d, Double.NaN));
300	}
301
302	// TODO: Test infinite bounds!
303	//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
304	//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),
305
306	/**
307	* nextDouble(least, bound) returns least <= value < bound;
308	* repeated calls produce at least two distinct results
309	*/
310	public void testNextDoubleBounded2() {
311	SplittableRandom sr = new SplittableRandom();
312	for (double least = 0.0001; least < 1.0e20; least *= 8) {
313	for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
314	double f = sr.nextDouble(least, bound);
315	assertTrue(least <= f && f < bound);
316	int i = 0;
317	double j;
318	while (i < NCALLS &&
319	(j = sr.nextDouble(least, bound)) == f) {
320	assertTrue(least <= j && j < bound);
321	++i;
322	}
323	assertTrue(i < NCALLS);
324	}
325	}
326	}
327
328	/**
329	* Invoking sized ints, long, doubles, with negative sizes throws
330	* IllegalArgumentException
331	*/
332	public void testBadStreamSize() {
333	SplittableRandom r = new SplittableRandom();
334	assertThrows(
335	IllegalArgumentException.class,
336	() -> { IntStream unused = r.ints(-1L); },
337	() -> { IntStream unused = r.ints(-1L, 2, 3); },
338	() -> { LongStream unused = r.longs(-1L); },
339	() -> { LongStream unused = r.longs(-1L, -1L, 1L); },
340	() -> { DoubleStream unused = r.doubles(-1L); },
341	() -> { DoubleStream unused = r.doubles(-1L, .5, .6); });
342	}
343
344	/**
345	* Invoking bounded ints, long, doubles, with illegal bounds throws
346	* IllegalArgumentException
347	*/
348	public void testBadStreamBounds() {
349	SplittableRandom r = new SplittableRandom();
350	assertThrows(
351	IllegalArgumentException.class,
352	() -> { IntStream unused = r.ints(2, 1); },
353	() -> { IntStream unused = r.ints(10, 42, 42); },
354	() -> { LongStream unused = r.longs(-1L, -1L); },
355	() -> { LongStream unused = r.longs(10, 1L, -2L); },
356	() -> { DoubleStream unused = r.doubles(0.0, 0.0); },
357	() -> { DoubleStream unused = r.doubles(10, .5, .4); });
358	}
359
360	/**
361	* A parallel sized stream of ints generates the given number of values
362	*/
363	public void testIntsCount() {
364	LongAdder counter = new LongAdder();
365	SplittableRandom r = new SplittableRandom();
366	long size = 0;
367	for (int reps = 0; reps < REPS; ++reps) {
368	counter.reset();
369	r.ints(size).parallel().forEach(x -> counter.increment());
370	assertEquals(size, counter.sum());
371	size += 524959;
372	}
373	}
374
375	/**
376	* A parallel sized stream of longs generates the given number of values
377	*/
378	public void testLongsCount() {
379	LongAdder counter = new LongAdder();
380	SplittableRandom r = new SplittableRandom();
381	long size = 0;
382	for (int reps = 0; reps < REPS; ++reps) {
383	counter.reset();
384	r.longs(size).parallel().forEach(x -> counter.increment());
385	assertEquals(size, counter.sum());
386	size += 524959;
387	}
388	}
389
390	/**
391	* A parallel sized stream of doubles generates the given number of values
392	*/
393	public void testDoublesCount() {
394	LongAdder counter = new LongAdder();
395	SplittableRandom r = new SplittableRandom();
396	long size = 0;
397	for (int reps = 0; reps < REPS; ++reps) {
398	counter.reset();
399	r.doubles(size).parallel().forEach(x -> counter.increment());
400	assertEquals(size, counter.sum());
401	size += 524959;
402	}
403	}
404
405	/**
406	* Each of a parallel sized stream of bounded ints is within bounds
407	*/
408	public void testBoundedInts() {
409	AtomicInteger fails = new AtomicInteger(0);
410	SplittableRandom r = new SplittableRandom();
411	long size = 12345L;
412	for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
413	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
414	final int lo = least, hi = bound;
415	r.ints(size, lo, hi).parallel().forEach(
416	x -> {
417	if (x < lo \|\| x >= hi)
418	fails.getAndIncrement(); });
419	}
420	}
421	assertEquals(0, fails.get());
422	}
423
424	/**
425	* Each of a parallel sized stream of bounded longs is within bounds
426	*/
427	public void testBoundedLongs() {
428	AtomicInteger fails = new AtomicInteger(0);
429	SplittableRandom r = new SplittableRandom();
430	long size = 123L;
431	for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
432	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
433	final long lo = least, hi = bound;
434	r.longs(size, lo, hi).parallel().forEach(
435	x -> {
436	if (x < lo \|\| x >= hi)
437	fails.getAndIncrement(); });
438	}
439	}
440	assertEquals(0, fails.get());
441	}
442
443	/**
444	* Each of a parallel sized stream of bounded doubles is within bounds
445	*/
446	public void testBoundedDoubles() {
447	AtomicInteger fails = new AtomicInteger(0);
448	SplittableRandom r = new SplittableRandom();
449	long size = 456;
450	for (double least = 0.00011; least < 1.0e20; least *= 9) {
451	for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
452	final double lo = least, hi = bound;
453	r.doubles(size, lo, hi).parallel().forEach(
454	x -> {
455	if (x < lo \|\| x >= hi)
456	fails.getAndIncrement(); });
457	}
458	}
459	assertEquals(0, fails.get());
460	}
461
462	/**
463	* A parallel unsized stream of ints generates at least 100 values
464	*/
465	public void testUnsizedIntsCount() {
466	LongAdder counter = new LongAdder();
467	SplittableRandom r = new SplittableRandom();
468	long size = 100;
469	r.ints().limit(size).parallel().forEach(x -> counter.increment());
470	assertEquals(size, counter.sum());
471	}
472
473	/**
474	* A parallel unsized stream of longs generates at least 100 values
475	*/
476	public void testUnsizedLongsCount() {
477	LongAdder counter = new LongAdder();
478	SplittableRandom r = new SplittableRandom();
479	long size = 100;
480	r.longs().limit(size).parallel().forEach(x -> counter.increment());
481	assertEquals(size, counter.sum());
482	}
483
484	/**
485	* A parallel unsized stream of doubles generates at least 100 values
486	*/
487	public void testUnsizedDoublesCount() {
488	LongAdder counter = new LongAdder();
489	SplittableRandom r = new SplittableRandom();
490	long size = 100;
491	r.doubles().limit(size).parallel().forEach(x -> counter.increment());
492	assertEquals(size, counter.sum());
493	}
494
495	/**
496	* A sequential unsized stream of ints generates at least 100 values
497	*/
498	public void testUnsizedIntsCountSeq() {
499	LongAdder counter = new LongAdder();
500	SplittableRandom r = new SplittableRandom();
501	long size = 100;
502	r.ints().limit(size).forEach(x -> counter.increment());
503	assertEquals(size, counter.sum());
504	}
505
506	/**
507	* A sequential unsized stream of longs generates at least 100 values
508	*/
509	public void testUnsizedLongsCountSeq() {
510	LongAdder counter = new LongAdder();
511	SplittableRandom r = new SplittableRandom();
512	long size = 100;
513	r.longs().limit(size).forEach(x -> counter.increment());
514	assertEquals(size, counter.sum());
515	}
516
517	/**
518	* A sequential unsized stream of doubles generates at least 100 values
519	*/
520	public void testUnsizedDoublesCountSeq() {
521	LongAdder counter = new LongAdder();
522	SplittableRandom r = new SplittableRandom();
523	long size = 100;
524	r.doubles().limit(size).forEach(x -> counter.increment());
525	assertEquals(size, counter.sum());
526	}
527
528	/**
529	* SplittableRandom should implement most of Random's public methods
530	*/
531	public void testShouldImplementMostRandomMethods() throws Throwable {
532	Predicate<Method> wasForgotten = method -> {
533	String name = method.getName();
534	// some methods deliberately not implemented
535	if (name.equals("setSeed")) return false;
536	if (name.equals("nextFloat")) return false;
537	if (name.equals("nextGaussian")) return false;
538	try {
539	SplittableRandom.class.getMethod(
540	method.getName(), method.getParameterTypes());
541	} catch (ReflectiveOperationException ex) {
542	return true;
543	}
544	return false;
545	};
546	List<Method> forgotten =
547	Arrays.stream(java.util.Random.class.getMethods())
548	.filter(wasForgotten)
549	.collect(Collectors.toList());
550	if (!forgotten.isEmpty())
551	throw new AssertionError("Please implement: " + forgotten);
552	}
553
554	/**
555	* Repeated calls to nextBytes produce at least values of different signs for every byte
556	*/
557	public void testNextBytes() {
558	SplittableRandom sr = new SplittableRandom();
559	int n = sr.nextInt(1, 20);
560	byte[] bytes = new byte[n];
561	outer:
562	for (int i = 0; i < n; i++) {
563	for (int tries = NCALLS; tries-->0; ) {
564	byte before = bytes[i];
565	sr.nextBytes(bytes);
566	byte after = bytes[i];
567	if (after * before < 0)
568	continue outer;
569	}
570	fail("not enough variation in random bytes");
571	}
572	}
573
574	/**
575	* Filling an empty array with random bytes succeeds without effect.
576	*/
577	public void testNextBytes_emptyArray() {
578	new SplittableRandom().nextBytes(new byte[0]);
579	}
580
581	public void testNextBytes_nullArray() {
582	try {
583	new SplittableRandom().nextBytes(null);
584	shouldThrow();
585	} catch (NullPointerException success) {}
586	}
587
588	}