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();
        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,
            () -> { 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); });
    }

    /**
     * Invoking bounded ints, long, doubles, with illegal bounds throws
     * IllegalArgumentException
     */
    public void testBadStreamBounds() {
        SplittableRandom r = new SplittableRandom();
        assertThrows(
            IllegalArgumentException.class,
            () -> { 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); });
    }

    /**
     * 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:	1.25
Committed:	Fri Feb 22 19:27:47 2019 UTC (5 years, 2 months ago) by jsr166
Branch:	MAIN
Changes since 1.24:	+24 -32 lines
Log Message:	improve assertThrows tests
#	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	assertThrows(
142	IllegalArgumentException.class,
143	() -> sr.nextInt(-17),
144	() -> sr.nextInt(0),
145	() -> sr.nextInt(Integer.MIN_VALUE));
146	}
147
148	/**
149	* nextInt(least >= bound) throws IllegalArgumentException
150	*/
151	public void testNextIntBadBounds() {
152	SplittableRandom sr = new SplittableRandom();
153	assertThrows(
154	IllegalArgumentException.class,
155	() -> sr.nextInt(17, 2),
156	() -> sr.nextInt(-42, -42),
157	() -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE));
158	}
159
160	/**
161	* nextInt(bound) returns 0 <= value < bound;
162	* repeated calls produce at least two distinct results
163	*/
164	public void testNextIntBounded() {
165	SplittableRandom sr = new SplittableRandom();
166	for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));
167	// sample bound space across prime number increments
168	for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
169	int f = sr.nextInt(bound);
170	assertTrue(0 <= f && f < bound);
171	int i = 0;
172	int j;
173	while (i < NCALLS &&
174	(j = sr.nextInt(bound)) == f) {
175	assertTrue(0 <= j && j < bound);
176	++i;
177	}
178	assertTrue(i < NCALLS);
179	}
180	}
181
182	/**
183	* nextInt(least, bound) returns least <= value < bound;
184	* repeated calls produce at least two distinct results
185	*/
186	public void testNextIntBounded2() {
187	SplittableRandom sr = new SplittableRandom();
188	for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {
189	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {
190	int f = sr.nextInt(least, bound);
191	assertTrue(least <= f && f < bound);
192	int i = 0;
193	int j;
194	while (i < NCALLS &&
195	(j = sr.nextInt(least, bound)) == f) {
196	assertTrue(least <= j && j < bound);
197	++i;
198	}
199	assertTrue(i < NCALLS);
200	}
201	}
202	}
203
204	/**
205	* nextLong(non-positive) throws IllegalArgumentException
206	*/
207	public void testNextLongBoundNonPositive() {
208	SplittableRandom sr = new SplittableRandom();
209	assertThrows(
210	IllegalArgumentException.class,
211	() -> sr.nextLong(-17L),
212	() -> sr.nextLong(0L),
213	() -> sr.nextLong(Long.MIN_VALUE));
214	}
215
216	/**
217	* nextLong(least >= bound) throws IllegalArgumentException
218	*/
219	public void testNextLongBadBounds() {
220	SplittableRandom sr = new SplittableRandom();
221	assertThrows(
222	IllegalArgumentException.class,
223	() -> sr.nextLong(17L, 2L),
224	() -> sr.nextLong(-42L, -42L),
225	() -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE));
226	}
227
228	/**
229	* nextLong(bound) returns 0 <= value < bound;
230	* repeated calls produce at least two distinct results
231	*/
232	public void testNextLongBounded() {
233	SplittableRandom sr = new SplittableRandom();
234	for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));
235	for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {
236	long f = sr.nextLong(bound);
237	assertTrue(0 <= f && f < bound);
238	int i = 0;
239	long j;
240	while (i < NCALLS &&
241	(j = sr.nextLong(bound)) == f) {
242	assertTrue(0 <= j && j < bound);
243	++i;
244	}
245	assertTrue(i < NCALLS);
246	}
247	}
248
249	/**
250	* nextLong(least, bound) returns least <= value < bound;
251	* repeated calls produce at least two distinct results
252	*/
253	public void testNextLongBounded2() {
254	SplittableRandom sr = new SplittableRandom();
255	for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {
256	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
257	long f = sr.nextLong(least, bound);
258	assertTrue(least <= f && f < bound);
259	int i = 0;
260	long j;
261	while (i < NCALLS &&
262	(j = sr.nextLong(least, bound)) == f) {
263	assertTrue(least <= j && j < bound);
264	++i;
265	}
266	assertTrue(i < NCALLS);
267	}
268	}
269	}
270
271	/**
272	* nextDouble(non-positive) throws IllegalArgumentException
273	*/
274	public void testNextDoubleBoundNonPositive() {
275	SplittableRandom sr = new SplittableRandom();
276	assertThrows(
277	IllegalArgumentException.class,
278	() -> sr.nextDouble(-17.0d),
279	() -> sr.nextDouble(0.0d),
280	() -> sr.nextDouble(-Double.MIN_VALUE),
281	() -> sr.nextDouble(Double.NEGATIVE_INFINITY),
282	() -> sr.nextDouble(Double.NaN));
283	}
284
285	/**
286	* nextDouble(! (least < bound)) throws IllegalArgumentException
287	*/
288	public void testNextDoubleBadBounds() {
289	SplittableRandom sr = new SplittableRandom();
290	assertThrows(
291	IllegalArgumentException.class,
292	() -> sr.nextDouble(17.0d, 2.0d),
293	() -> sr.nextDouble(-42.0d, -42.0d),
294	() -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),
295	() -> sr.nextDouble(Double.NaN, 0.0d),
296	() -> sr.nextDouble(0.0d, Double.NaN));
297	}
298
299	// TODO: Test infinite bounds!
300	//() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),
301	//() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),
302
303	/**
304	* nextDouble(least, bound) returns least <= value < bound;
305	* repeated calls produce at least two distinct results
306	*/
307	public void testNextDoubleBounded2() {
308	SplittableRandom sr = new SplittableRandom();
309	for (double least = 0.0001; least < 1.0e20; least *= 8) {
310	for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {
311	double f = sr.nextDouble(least, bound);
312	assertTrue(least <= f && f < bound);
313	int i = 0;
314	double j;
315	while (i < NCALLS &&
316	(j = sr.nextDouble(least, bound)) == f) {
317	assertTrue(least <= j && j < bound);
318	++i;
319	}
320	assertTrue(i < NCALLS);
321	}
322	}
323	}
324
325	/**
326	* Invoking sized ints, long, doubles, with negative sizes throws
327	* IllegalArgumentException
328	*/
329	public void testBadStreamSize() {
330	SplittableRandom r = new SplittableRandom();
331	assertThrows(
332	IllegalArgumentException.class,
333	() -> { java.util.stream.IntStream x = r.ints(-1L); },
334	() -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },
335	() -> { java.util.stream.LongStream x = r.longs(-1L); },
336	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },
337	() -> { java.util.stream.DoubleStream x = r.doubles(-1L); },
338	() -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); });
339	}
340
341	/**
342	* Invoking bounded ints, long, doubles, with illegal bounds throws
343	* IllegalArgumentException
344	*/
345	public void testBadStreamBounds() {
346	SplittableRandom r = new SplittableRandom();
347	assertThrows(
348	IllegalArgumentException.class,
349	() -> { java.util.stream.IntStream x = r.ints(2, 1); },
350	() -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },
351	() -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },
352	() -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },
353	() -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },
354	() -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); });
355	}
356
357	/**
358	* A parallel sized stream of ints generates the given number of values
359	*/
360	public void testIntsCount() {
361	LongAdder counter = new LongAdder();
362	SplittableRandom r = new SplittableRandom();
363	long size = 0;
364	for (int reps = 0; reps < REPS; ++reps) {
365	counter.reset();
366	r.ints(size).parallel().forEach(x -> counter.increment());
367	assertEquals(size, counter.sum());
368	size += 524959;
369	}
370	}
371
372	/**
373	* A parallel sized stream of longs generates the given number of values
374	*/
375	public void testLongsCount() {
376	LongAdder counter = new LongAdder();
377	SplittableRandom r = new SplittableRandom();
378	long size = 0;
379	for (int reps = 0; reps < REPS; ++reps) {
380	counter.reset();
381	r.longs(size).parallel().forEach(x -> counter.increment());
382	assertEquals(size, counter.sum());
383	size += 524959;
384	}
385	}
386
387	/**
388	* A parallel sized stream of doubles generates the given number of values
389	*/
390	public void testDoublesCount() {
391	LongAdder counter = new LongAdder();
392	SplittableRandom r = new SplittableRandom();
393	long size = 0;
394	for (int reps = 0; reps < REPS; ++reps) {
395	counter.reset();
396	r.doubles(size).parallel().forEach(x -> counter.increment());
397	assertEquals(size, counter.sum());
398	size += 524959;
399	}
400	}
401
402	/**
403	* Each of a parallel sized stream of bounded ints is within bounds
404	*/
405	public void testBoundedInts() {
406	AtomicInteger fails = new AtomicInteger(0);
407	SplittableRandom r = new SplittableRandom();
408	long size = 12345L;
409	for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {
410	for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {
411	final int lo = least, hi = bound;
412	r.ints(size, lo, hi).parallel().forEach(
413	x -> {
414	if (x < lo \|\| x >= hi)
415	fails.getAndIncrement(); });
416	}
417	}
418	assertEquals(0, fails.get());
419	}
420
421	/**
422	* Each of a parallel sized stream of bounded longs is within bounds
423	*/
424	public void testBoundedLongs() {
425	AtomicInteger fails = new AtomicInteger(0);
426	SplittableRandom r = new SplittableRandom();
427	long size = 123L;
428	for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {
429	for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {
430	final long lo = least, hi = bound;
431	r.longs(size, lo, hi).parallel().forEach(
432	x -> {
433	if (x < lo \|\| x >= hi)
434	fails.getAndIncrement(); });
435	}
436	}
437	assertEquals(0, fails.get());
438	}
439
440	/**
441	* Each of a parallel sized stream of bounded doubles is within bounds
442	*/
443	public void testBoundedDoubles() {
444	AtomicInteger fails = new AtomicInteger(0);
445	SplittableRandom r = new SplittableRandom();
446	long size = 456;
447	for (double least = 0.00011; least < 1.0e20; least *= 9) {
448	for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {
449	final double lo = least, hi = bound;
450	r.doubles(size, lo, hi).parallel().forEach(
451	x -> {
452	if (x < lo \|\| x >= hi)
453	fails.getAndIncrement(); });
454	}
455	}
456	assertEquals(0, fails.get());
457	}
458
459	/**
460	* A parallel unsized stream of ints generates at least 100 values
461	*/
462	public void testUnsizedIntsCount() {
463	LongAdder counter = new LongAdder();
464	SplittableRandom r = new SplittableRandom();
465	long size = 100;
466	r.ints().limit(size).parallel().forEach(x -> counter.increment());
467	assertEquals(size, counter.sum());
468	}
469
470	/**
471	* A parallel unsized stream of longs generates at least 100 values
472	*/
473	public void testUnsizedLongsCount() {
474	LongAdder counter = new LongAdder();
475	SplittableRandom r = new SplittableRandom();
476	long size = 100;
477	r.longs().limit(size).parallel().forEach(x -> counter.increment());
478	assertEquals(size, counter.sum());
479	}
480
481	/**
482	* A parallel unsized stream of doubles generates at least 100 values
483	*/
484	public void testUnsizedDoublesCount() {
485	LongAdder counter = new LongAdder();
486	SplittableRandom r = new SplittableRandom();
487	long size = 100;
488	r.doubles().limit(size).parallel().forEach(x -> counter.increment());
489	assertEquals(size, counter.sum());
490	}
491
492	/**
493	* A sequential unsized stream of ints generates at least 100 values
494	*/
495	public void testUnsizedIntsCountSeq() {
496	LongAdder counter = new LongAdder();
497	SplittableRandom r = new SplittableRandom();
498	long size = 100;
499	r.ints().limit(size).forEach(x -> counter.increment());
500	assertEquals(size, counter.sum());
501	}
502
503	/**
504	* A sequential unsized stream of longs generates at least 100 values
505	*/
506	public void testUnsizedLongsCountSeq() {
507	LongAdder counter = new LongAdder();
508	SplittableRandom r = new SplittableRandom();
509	long size = 100;
510	r.longs().limit(size).forEach(x -> counter.increment());
511	assertEquals(size, counter.sum());
512	}
513
514	/**
515	* A sequential unsized stream of doubles generates at least 100 values
516	*/
517	public void testUnsizedDoublesCountSeq() {
518	LongAdder counter = new LongAdder();
519	SplittableRandom r = new SplittableRandom();
520	long size = 100;
521	r.doubles().limit(size).forEach(x -> counter.increment());
522	assertEquals(size, counter.sum());
523	}
524
525	/**
526	* SplittableRandom should implement most of Random's public methods
527	*/
528	public void testShouldImplementMostRandomMethods() throws Throwable {
529	Predicate<Method> wasForgotten = method -> {
530	String name = method.getName();
531	// some methods deliberately not implemented
532	if (name.equals("setSeed")) return false;
533	if (name.equals("nextFloat")) return false;
534	if (name.equals("nextGaussian")) return false;
535	try {
536	SplittableRandom.class.getMethod(
537	method.getName(), method.getParameterTypes());
538	} catch (ReflectiveOperationException ex) {
539	return true;
540	}
541	return false;
542	};
543	List<Method> forgotten =
544	Arrays.stream(java.util.Random.class.getMethods())
545	.filter(wasForgotten)
546	.collect(Collectors.toList());
547	if (!forgotten.isEmpty())
548	throw new AssertionError("Please implement: " + forgotten);
549	}
550
551	/**
552	* Repeated calls to nextBytes produce at least values of different signs for every byte
553	*/
554	public void testNextBytes() {
555	SplittableRandom sr = new SplittableRandom();
556	int n = sr.nextInt(1, 20);
557	byte[] bytes = new byte[n];
558	outer:
559	for (int i = 0; i < n; i++) {
560	for (int tries = NCALLS; tries-->0; ) {
561	byte before = bytes[i];
562	sr.nextBytes(bytes);
563	byte after = bytes[i];
564	if (after * before < 0)
565	continue outer;
566	}
567	fail("not enough variation in random bytes");
568	}
569	}
570
571	/**
572	* Filling an empty array with random bytes succeeds without effect.
573	*/
574	public void testNextBytes_emptyArray() {
575	new SplittableRandom().nextBytes(new byte[0]);
576	}
577
578	public void testNextBytes_nullArray() {
579	try {
580	new SplittableRandom().nextBytes(null);
581	shouldThrow();
582	} catch (NullPointerException success) {}
583	}
584
585	}