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 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(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:	1.24
Committed:	Fri Oct 13 16:14:40 2017 UTC (6 years, 7 months ago) by jsr166
Branch:	MAIN
Changes since 1.23:	+0 -1 lines
Log Message:	remove unused imports
#	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
16	import junit.framework.Test;
17	import junit.framework.TestSuite;
18
19	public class SplittableRandomTest extends JSR166TestCase {
20
21	public static void main(String[] args) {
22	main(suite(), args);
23	}
24	public static Test suite() {
25	return new TestSuite(SplittableRandomTest.class);
26	}
27
28	/*
29	* Testing coverage notes:
30	*
31	* 1. Many of the test methods are adapted from ThreadLocalRandomTest.
32	*
33	* 2. These tests do not check for random number generator quality.
34	* But we check for minimal API compliance by requiring that
35	* repeated calls to nextX methods, up to NCALLS tries, produce at
36	* least two distinct results. (In some possible universe, a
37	* "correct" implementation might fail, but the odds are vastly
38	* less than that of encountering a hardware failure while running
39	* the test.) For bounded nextX methods, we sample various
40	* intervals across multiples of primes. In other tests, we repeat
41	* under REPS different values.
42	*/
43
44	// max numbers of calls to detect getting stuck on one value
45	static final int NCALLS = 10000;
46
47	// max sampled int bound
48	static final int MAX_INT_BOUND = (1 << 26);
49
50	// max sampled long bound
51	static final long MAX_LONG_BOUND = (1L << 40);
52
53	// Number of replications for other checks
54	static final int REPS =
55	Integer.getInteger("SplittableRandomTest.reps", 4);
56
57	/**
58	* Repeated calls to nextInt produce at least two distinct results
59	*/
60	public void testNextInt() {
61	SplittableRandom sr = new SplittableRandom();
62	int f = sr.nextInt();
63	int i = 0;
64	while (i < NCALLS && sr.nextInt() == f)
65	++i;
66	assertTrue(i < NCALLS);
67	}
68
69	/**
70	* Repeated calls to nextLong produce at least two distinct results
71	*/
72	public void testNextLong() {
73	SplittableRandom sr = new SplittableRandom();
74	long f = sr.nextLong();
75	int i = 0;
76	while (i < NCALLS && sr.nextLong() == f)
77	++i;
78	assertTrue(i < NCALLS);
79	}
80
81	/**
82	* Repeated calls to nextDouble produce at least two distinct results
83	*/
84	public void testNextDouble() {
85	SplittableRandom sr = new SplittableRandom();
86	double f = sr.nextDouble();
87	int i = 0;
88	while (i < NCALLS && sr.nextDouble() == f)
89	++i;
90	assertTrue(i < NCALLS);
91	}
92
93	/**
94	* Two SplittableRandoms created with the same seed produce the
95	* same values for nextLong.
96	*/
97	public void testSeedConstructor() {
98	for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {
99	SplittableRandom sr1 = new SplittableRandom(seed);
100	SplittableRandom sr2 = new SplittableRandom(seed);
101	for (int i = 0; i < REPS; ++i)
102	assertEquals(sr1.nextLong(), sr2.nextLong());
103	}
104	}
105
106	/**
107	* A SplittableRandom produced by split() of a default-constructed
108	* SplittableRandom generates a different sequence
109	*/
110	public void testSplit1() {
111	SplittableRandom sr = new SplittableRandom();
112	for (int reps = 0; reps < REPS; ++reps) {
113	SplittableRandom sc = sr.split();
114	int i = 0;
115	while (i < NCALLS && sr.nextLong() == sc.nextLong())
116	++i;
117	assertTrue(i < NCALLS);
118	}
119	}
120
121	/**
122	* A SplittableRandom produced by split() of a seeded-constructed
123	* SplittableRandom generates a different sequence
124	*/
125	public void testSplit2() {
126	SplittableRandom sr = new SplittableRandom(12345);
127	for (int reps = 0; reps < REPS; ++reps) {
128	SplittableRandom sc = sr.split();
129	int i = 0;
130	while (i < NCALLS && sr.nextLong() == sc.nextLong())
131	++i;
132	assertTrue(i < NCALLS);
133	}
134	}
135
136	/**
137	* nextInt(non-positive) throws IllegalArgumentException
138	*/
139	public void testNextIntBoundNonPositive() {
140	SplittableRandom sr = new SplittableRandom();
141	Runnable[] throwingActions = {
142	() -> sr.nextInt(-17),
143	() -> sr.nextInt(0),
144	() -> sr.nextInt(Integer.MIN_VALUE),
145	};
146	assertThrows(IllegalArgumentException.class, throwingActions);
147	}
148
149	/**
150	* nextInt(least >= bound) throws IllegalArgumentException
151	*/
152	public void testNextIntBadBounds() {
153	SplittableRandom sr = new SplittableRandom();
154	Runnable[] throwingActions = {
155	() -> sr.nextInt(17, 2),
156	() -> sr.nextInt(-42, -42),
157	() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE),
158	};
159	assertThrows(IllegalArgumentException.class, throwingActions);
160	}
161
162	/**
163	* nextInt(bound) returns 0 <= value < bound;
164	* repeated calls produce at least two distinct results
165	*/
166	public void testNextIntBounded() {
167	SplittableRandom sr = new SplittableRandom();
168	for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
169	// sample bound space across prime number increments
170	for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
171	int f = sr.nextInt(bound);
172	assertTrue(0 <= f && f < bound);
173	int i = 0;
174	int j;
175	while (i < NCALLS &&
176	(j = sr.nextInt(bound)) == f) {
177	assertTrue(0 <= j && j < bound);
178	++i;
179	}
180	assertTrue(i < NCALLS);
181	}
182	}
183
184	/**
185	* nextInt(least, bound) returns least <= value < bound;
186	* repeated calls produce at least two distinct results
187	*/
188	public void testNextIntBounded2() {
189	SplittableRandom sr = new SplittableRandom();
190	for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
191	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
192	int f = sr.nextInt(least, bound);
193	assertTrue(least <= f && f < bound);
194	int i = 0;
195	int j;
196	while (i < NCALLS &&
197	(j = sr.nextInt(least, bound)) == f) {
198	assertTrue(least <= j && j < bound);
199	++i;
200	}
201	assertTrue(i < NCALLS);
202	}
203	}
204	}
205
206	/**
207	* nextLong(non-positive) throws IllegalArgumentException
208	*/
209	public void testNextLongBoundNonPositive() {
210	SplittableRandom sr = new SplittableRandom();
211	Runnable[] throwingActions = {
212	() -> sr.nextLong(-17L),
213	() -> sr.nextLong(0L),
214	() -> sr.nextLong(Long.MIN_VALUE),
215	};
216	assertThrows(IllegalArgumentException.class, throwingActions);
217	}
218
219	/**
220	* nextLong(least >= bound) throws IllegalArgumentException
221	*/
222	public void testNextLongBadBounds() {
223	SplittableRandom sr = new SplittableRandom();
224	Runnable[] throwingActions = {
225	() -> sr.nextLong(17L, 2L),
226	() -> sr.nextLong(-42L, -42L),
227	() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE),
228	};
229	assertThrows(IllegalArgumentException.class, throwingActions);
230	}
231
232	/**
233	* nextLong(bound) returns 0 <= value < bound;
234	* repeated calls produce at least two distinct results
235	*/
236	public void testNextLongBounded() {
237	SplittableRandom sr = new SplittableRandom();
238	for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
239	for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
240	long f = sr.nextLong(bound);
241	assertTrue(0 <= f && f < bound);
242	int i = 0;
243	long j;
244	while (i < NCALLS &&
245	(j = sr.nextLong(bound)) == f) {
246	assertTrue(0 <= j && j < bound);
247	++i;
248	}
249	assertTrue(i < NCALLS);
250	}
251	}
252
253	/**
254	* nextLong(least, bound) returns least <= value < bound;
255	* repeated calls produce at least two distinct results
256	*/
257	public void testNextLongBounded2() {
258	SplittableRandom sr = new SplittableRandom();
259	for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
260	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
261	long f = sr.nextLong(least, bound);
262	assertTrue(least <= f && f < bound);
263	int i = 0;
264	long j;
265	while (i < NCALLS &&
266	(j = sr.nextLong(least, bound)) == f) {
267	assertTrue(least <= j && j < bound);
268	++i;
269	}
270	assertTrue(i < NCALLS);
271	}
272	}
273	}
274
275	/**
276	* nextDouble(non-positive) throws IllegalArgumentException
277	*/
278	public void testNextDoubleBoundNonPositive() {
279	SplittableRandom sr = new SplittableRandom();
280	Runnable[] throwingActions = {
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	assertThrows(IllegalArgumentException.class, throwingActions);
288	}
289
290	/**
291	* nextDouble(! (least < bound)) throws IllegalArgumentException
292	*/
293	public void testNextDoubleBadBounds() {
294	SplittableRandom sr = new SplittableRandom();
295	Runnable[] throwingActions = {
296	() -> sr.nextDouble(17.0d, 2.0d),
297	() -> sr.nextDouble(-42.0d, -42.0d),
298	() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
299	() -> sr.nextDouble(Double.NaN, 0.0d),
300	() -> sr.nextDouble(0.0d, Double.NaN),
301	};
302	assertThrows(IllegalArgumentException.class, throwingActions);
303	}
304
305	// TODO: Test infinite bounds!
306	//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
307	//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),
308
309	/**
310	* nextDouble(least, bound) returns least <= value < bound;
311	* repeated calls produce at least two distinct results
312	*/
313	public void testNextDoubleBounded2() {
314	SplittableRandom sr = new SplittableRandom();
315	for (double least = 0.0001; least < 1.0e20; least *= 8) {
316	for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
317	double f = sr.nextDouble(least, bound);
318	assertTrue(least <= f && f < bound);
319	int i = 0;
320	double j;
321	while (i < NCALLS &&
322	(j = sr.nextDouble(least, bound)) == f) {
323	assertTrue(least <= j && j < bound);
324	++i;
325	}
326	assertTrue(i < NCALLS);
327	}
328	}
329	}
330
331	/**
332	* Invoking sized ints, long, doubles, with negative sizes throws
333	* IllegalArgumentException
334	*/
335	public void testBadStreamSize() {
336	SplittableRandom r = new SplittableRandom();
337	Runnable[] throwingActions = {
338	() -> { java.util.stream.IntStream x = r.ints(-1L); },
339	() -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
340	() -> { java.util.stream.LongStream x = r.longs(-1L); },
341	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
342	() -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
343	() -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); },
344	};
345	assertThrows(IllegalArgumentException.class, throwingActions);
346	}
347
348	/**
349	* Invoking bounded ints, long, doubles, with illegal bounds throws
350	* IllegalArgumentException
351	*/
352	public void testBadStreamBounds() {
353	SplittableRandom r = new SplittableRandom();
354	Runnable[] throwingActions = {
355	() -> { java.util.stream.IntStream x = r.ints(2, 1); },
356	() -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
357	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
358	() -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
359	() -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
360	() -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); },
361	};
362	assertThrows(IllegalArgumentException.class, throwingActions);
363	}
364
365	/**
366	* A parallel sized stream of ints generates the given number of values
367	*/
368	public void testIntsCount() {
369	LongAdder counter = new LongAdder();
370	SplittableRandom r = new SplittableRandom();
371	long size = 0;
372	for (int reps = 0; reps < REPS; ++reps) {
373	counter.reset();
374	r.ints(size).parallel().forEach(x -> counter.increment());
375	assertEquals(size, counter.sum());
376	size += 524959;
377	}
378	}
379
380	/**
381	* A parallel sized stream of longs generates the given number of values
382	*/
383	public void testLongsCount() {
384	LongAdder counter = new LongAdder();
385	SplittableRandom r = new SplittableRandom();
386	long size = 0;
387	for (int reps = 0; reps < REPS; ++reps) {
388	counter.reset();
389	r.longs(size).parallel().forEach(x -> counter.increment());
390	assertEquals(size, counter.sum());
391	size += 524959;
392	}
393	}
394
395	/**
396	* A parallel sized stream of doubles generates the given number of values
397	*/
398	public void testDoublesCount() {
399	LongAdder counter = new LongAdder();
400	SplittableRandom r = new SplittableRandom();
401	long size = 0;
402	for (int reps = 0; reps < REPS; ++reps) {
403	counter.reset();
404	r.doubles(size).parallel().forEach(x -> counter.increment());
405	assertEquals(size, counter.sum());
406	size += 524959;
407	}
408	}
409
410	/**
411	* Each of a parallel sized stream of bounded ints is within bounds
412	*/
413	public void testBoundedInts() {
414	AtomicInteger fails = new AtomicInteger(0);
415	SplittableRandom r = new SplittableRandom();
416	long size = 12345L;
417	for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
418	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
419	final int lo = least, hi = bound;
420	r.ints(size, lo, hi).parallel().forEach(
421	x -> {
422	if (x < lo \|\| x >= hi)
423	fails.getAndIncrement(); });
424	}
425	}
426	assertEquals(0, fails.get());
427	}
428
429	/**
430	* Each of a parallel sized stream of bounded longs is within bounds
431	*/
432	public void testBoundedLongs() {
433	AtomicInteger fails = new AtomicInteger(0);
434	SplittableRandom r = new SplittableRandom();
435	long size = 123L;
436	for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
437	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
438	final long lo = least, hi = bound;
439	r.longs(size, lo, hi).parallel().forEach(
440	x -> {
441	if (x < lo \|\| x >= hi)
442	fails.getAndIncrement(); });
443	}
444	}
445	assertEquals(0, fails.get());
446	}
447
448	/**
449	* Each of a parallel sized stream of bounded doubles is within bounds
450	*/
451	public void testBoundedDoubles() {
452	AtomicInteger fails = new AtomicInteger(0);
453	SplittableRandom r = new SplittableRandom();
454	long size = 456;
455	for (double least = 0.00011; least < 1.0e20; least *= 9) {
456	for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
457	final double lo = least, hi = bound;
458	r.doubles(size, lo, hi).parallel().forEach(
459	x -> {
460	if (x < lo \|\| x >= hi)
461	fails.getAndIncrement(); });
462	}
463	}
464	assertEquals(0, fails.get());
465	}
466
467	/**
468	* A parallel unsized stream of ints generates at least 100 values
469	*/
470	public void testUnsizedIntsCount() {
471	LongAdder counter = new LongAdder();
472	SplittableRandom r = new SplittableRandom();
473	long size = 100;
474	r.ints().limit(size).parallel().forEach(x -> counter.increment());
475	assertEquals(size, counter.sum());
476	}
477
478	/**
479	* A parallel unsized stream of longs generates at least 100 values
480	*/
481	public void testUnsizedLongsCount() {
482	LongAdder counter = new LongAdder();
483	SplittableRandom r = new SplittableRandom();
484	long size = 100;
485	r.longs().limit(size).parallel().forEach(x -> counter.increment());
486	assertEquals(size, counter.sum());
487	}
488
489	/**
490	* A parallel unsized stream of doubles generates at least 100 values
491	*/
492	public void testUnsizedDoublesCount() {
493	LongAdder counter = new LongAdder();
494	SplittableRandom r = new SplittableRandom();
495	long size = 100;
496	r.doubles().limit(size).parallel().forEach(x -> counter.increment());
497	assertEquals(size, counter.sum());
498	}
499
500	/**
501	* A sequential unsized stream of ints generates at least 100 values
502	*/
503	public void testUnsizedIntsCountSeq() {
504	LongAdder counter = new LongAdder();
505	SplittableRandom r = new SplittableRandom();
506	long size = 100;
507	r.ints().limit(size).forEach(x -> counter.increment());
508	assertEquals(size, counter.sum());
509	}
510
511	/**
512	* A sequential unsized stream of longs generates at least 100 values
513	*/
514	public void testUnsizedLongsCountSeq() {
515	LongAdder counter = new LongAdder();
516	SplittableRandom r = new SplittableRandom();
517	long size = 100;
518	r.longs().limit(size).forEach(x -> counter.increment());
519	assertEquals(size, counter.sum());
520	}
521
522	/**
523	* A sequential unsized stream of doubles generates at least 100 values
524	*/
525	public void testUnsizedDoublesCountSeq() {
526	LongAdder counter = new LongAdder();
527	SplittableRandom r = new SplittableRandom();
528	long size = 100;
529	r.doubles().limit(size).forEach(x -> counter.increment());
530	assertEquals(size, counter.sum());
531	}
532
533	/**
534	* SplittableRandom should implement most of Random's public methods
535	*/
536	public void testShouldImplementMostRandomMethods() throws Throwable {
537	Predicate<Method> wasForgotten = method -> {
538	String name = method.getName();
539	// some methods deliberately not implemented
540	if (name.equals("setSeed")) return false;
541	if (name.equals("nextFloat")) return false;
542	if (name.equals("nextGaussian")) return false;
543	try {
544	SplittableRandom.class.getMethod(
545	method.getName(), method.getParameterTypes());
546	} catch (ReflectiveOperationException ex) {
547	return true;
548	}
549	return false;
550	};
551	List<Method> forgotten =
552	Arrays.stream(java.util.Random.class.getMethods())
553	.filter(wasForgotten)
554	.collect(Collectors.toList());
555	if (!forgotten.isEmpty())
556	throw new AssertionError("Please implement: " + forgotten);
557	}
558
559	/**
560	* Repeated calls to nextBytes produce at least values of different signs for every byte
561	*/
562	public void testNextBytes() {
563	SplittableRandom sr = new SplittableRandom();
564	int n = sr.nextInt(1, 20);
565	byte[] bytes = new byte[n];
566	outer:
567	for (int i = 0; i < n; i++) {
568	for (int tries = NCALLS; tries-->0; ) {
569	byte before = bytes[i];
570	sr.nextBytes(bytes);
571	byte after = bytes[i];
572	if (after * before < 0)
573	continue outer;
574	}
575	fail("not enough variation in random bytes");
576	}
577	}
578
579	/**
580	* Filling an empty array with random bytes succeeds without effect.
581	*/
582	public void testNextBytes_emptyArray() {
583	new SplittableRandom().nextBytes(new byte[0]);
584	}
585
586	public void testNextBytes_nullArray() {
587	try {
588	new SplittableRandom().nextBytes(null);
589	shouldThrow();
590	} catch (NullPointerException success) {}
591	}
592
593	}