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/*
* Copyright (c) 2012, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.LongAdder;
import java.util.function.BiConsumer;
import java.util.random.RandomGenerator;
import java.util.ArrayList;
import java.util.Collections;
import org.testng.annotations.Test;
import static org.testng.Assert.*;
/**
* @test
* @run testng RandomTest
* @summary test methods on Random
* @bug 8288596
* @key randomness
*/
@Test
public class RandomTest {
// Note: this test was adapted from the 166 TCK ThreadLocalRandomTest test
// and modified to be a TestNG test
/*
* Testing coverage notes:
*
* We don't test randomness properties, but only that repeated
* calls, up to NCALLS tries, produce at least one different
* result. For bounded versions, we sample various intervals
* across multiples of primes.
*/
// max numbers of calls to detect getting stuck on one value
static final int NCALLS = 10000;
// max sampled int bound
static final int MAX_INT_BOUND = (1 << 28);
// max sampled long bound
static final long MAX_LONG_BOUND = (1L << 42);
// Number of replications for other checks
static final int REPS = 20;
/**
* Repeated calls to nextInt produce at least two distinct results
*/
public void testNextInt() {
Random r = new Random();
int f = r.nextInt();
int i = 0;
while (i < NCALLS && r.nextInt() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* Repeated calls to nextLong produce at least two distinct results
*/
public void testNextLong() {
Random r = new Random();
long f = r.nextLong();
int i = 0;
while (i < NCALLS && r.nextLong() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* Repeated calls to nextBoolean produce at least two distinct results
*/
public void testNextBoolean() {
Random r = new Random();
boolean f = r.nextBoolean();
int i = 0;
while (i < NCALLS && r.nextBoolean() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* Repeated calls to nextFloat produce at least two distinct results
*/
public void testNextFloat() {
Random r = new Random();
float f = r.nextFloat();
int i = 0;
while (i < NCALLS && r.nextFloat() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* Repeated calls to nextDouble produce at least two distinct results
*/
public void testNextDouble() {
Random r = new Random();
double f = r.nextDouble();
int i = 0;
while (i < NCALLS && r.nextDouble() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* Repeated calls to nextGaussian produce at least two distinct results
*/
public void testNextGaussian() {
Random r = new Random();
double f = r.nextGaussian();
int i = 0;
while (i < NCALLS && r.nextGaussian() == f)
++i;
assertTrue(i < NCALLS);
}
/**
* nextInt(negative) throws IllegalArgumentException
*/
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNextIntBoundedNeg() {
Random r = new Random();
int f = r.nextInt(-17);
}
/**
* nextInt(bound) returns 0 <= value < bound; repeated calls produce at
* least two distinct results
*/
public void testNextIntBounded() {
Random r = new Random();
// sample bound space across prime number increments
for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {
int f = r.nextInt(bound);
assertTrue(0 <= f && f < bound);
int i = 0;
int j;
while (i < NCALLS &&
(j = r.nextInt(bound)) == f) {
assertTrue(0 <= j && j < bound);
++i;
}
assertTrue(i < NCALLS);
}
}
/**
* Invoking sized ints, long, doubles, with negative sizes throws
* IllegalArgumentException
*/
public void testBadStreamSize() {
Random r = new Random();
assertThrowsIAE(() -> r.ints(-1L));
assertThrowsIAE(() -> r.ints(-1L, 2, 3));
assertThrowsIAE(() -> r.longs(-1L));
assertThrowsIAE(() -> r.longs(-1L, -1L, 1L));
assertThrowsIAE(() -> r.doubles(-1L));
assertThrowsIAE(() -> r.doubles(-1L, .5, .6));
}
/**
* Invoking bounded ints, long, doubles, with illegal bounds throws
* IllegalArgumentException
*/
public void testBadStreamBounds() {
Random r = new Random();
assertThrowsIAE(() -> r.ints(2, 1));
assertThrowsIAE(() -> r.ints(10, 42, 42));
assertThrowsIAE(() -> r.longs(-1L, -1L));
assertThrowsIAE(() -> r.longs(10, 1L, -2L));
testDoubleBadOriginBound((o, b) -> r.doubles(10, o, b));
}
// An arbitrary finite double value
static final double FINITE = Math.PI;
void testDoubleBadOriginBound(BiConsumer<Double, Double> bi) {
assertThrowsIAE(() -> bi.accept(17.0, 2.0));
assertThrowsIAE(() -> bi.accept(0.0, 0.0));
assertThrowsIAE(() -> bi.accept(Double.NaN, FINITE));
assertThrowsIAE(() -> bi.accept(FINITE, Double.NaN));
assertThrowsIAE(() -> bi.accept(Double.NEGATIVE_INFINITY, Double.NEGATIVE_INFINITY));
// Returns NaN
// assertThrowsIAE(() -> bi.accept(Double.NEGATIVE_INFINITY, FINITE));
// assertThrowsIAE(() -> bi.accept(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY));
assertThrowsIAE(() -> bi.accept(FINITE, Double.NEGATIVE_INFINITY));
// Returns Double.MAX_VALUE
// assertThrowsIAE(() -> bi.accept(FINITE, Double.POSITIVE_INFINITY));
assertThrowsIAE(() -> bi.accept(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY));
assertThrowsIAE(() -> bi.accept(Double.POSITIVE_INFINITY, FINITE));
assertThrowsIAE(() -> bi.accept(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY));
}
private void assertThrowsIAE(ThrowingRunnable r) {
assertThrows(IllegalArgumentException.class, r);
}
/**
* A sequential sized stream of ints generates the given number of values
*/
public void testIntsCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 0;
for (int reps = 0; reps < REPS; ++reps) {
counter.reset();
r.ints(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
size += 524959;
}
}
/**
* A sequential sized stream of longs generates the given number of values
*/
public void testLongsCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 0;
for (int reps = 0; reps < REPS; ++reps) {
counter.reset();
r.longs(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
size += 524959;
}
}
/**
* A sequential sized stream of doubles generates the given number of values
*/
public void testDoublesCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 0;
for (int reps = 0; reps < REPS; ++reps) {
counter.reset();
r.doubles(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
size += 524959;
}
}
/**
* Each of a sequential sized stream of bounded ints is within bounds
*/
public void testBoundedInts() {
AtomicInteger fails = new AtomicInteger(0);
Random r = new Random();
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).
forEach(x -> {
if (x < lo || x >= hi)
fails.getAndIncrement();
});
}
}
assertEquals(fails.get(), 0);
}
/**
* Each of a sequential sized stream of bounded longs is within bounds
*/
public void testBoundedLongs() {
AtomicInteger fails = new AtomicInteger(0);
Random r = new Random();
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).
forEach(x -> {
if (x < lo || x >= hi)
fails.getAndIncrement();
});
}
}
assertEquals(fails.get(), 0);
}
/**
* Each of a sequential sized stream of bounded doubles is within bounds
*/
public void testBoundedDoubles() {
AtomicInteger fails = new AtomicInteger(0);
Random r = new Random();
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).
forEach(x -> {
if (x < lo || x >= hi)
fails.getAndIncrement();
});
}
}
assertEquals(fails.get(), 0);
}
/**
* A parallel unsized stream of ints generates at least 100 values
*/
public void testUnsizedIntsCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.ints().limit(size).parallel().forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* A parallel unsized stream of longs generates at least 100 values
*/
public void testUnsizedLongsCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.longs().limit(size).parallel().forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* A parallel unsized stream of doubles generates at least 100 values
*/
public void testUnsizedDoublesCount() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.doubles().limit(size).parallel().forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* A sequential unsized stream of ints generates at least 100 values
*/
public void testUnsizedIntsCountSeq() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.ints().limit(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* A sequential unsized stream of longs generates at least 100 values
*/
public void testUnsizedLongsCountSeq() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.longs().limit(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* A sequential unsized stream of doubles generates at least 100 values
*/
public void testUnsizedDoublesCountSeq() {
LongAdder counter = new LongAdder();
Random r = new Random();
long size = 100;
r.doubles().limit(size).forEach(x -> {
counter.increment();
});
assertEquals(counter.sum(), size);
}
/**
* Test shuffling a list with Random.from()
*/
public void testShufflingList() {
final var listTest = new ArrayList<Integer>();
final RandomGenerator randomGenerator = RandomGenerator.getDefault();
final Random random = Random.from(randomGenerator);
for (int i = 0; i < 100; i++) {
listTest.add(i * 2);
}
final var listCopy = new ArrayList<Integer>(listTest);
Collections.shuffle(listCopy, random);
assertFalse(listCopy.equals(listTest));
}
/**
* Test if Random.from returns this
*/
public void testRandomFromInstance() {
final RandomGenerator randomGenerator = RandomGenerator.getDefault();
final Random randomInstance = Random.from(randomGenerator);
// we wrap the same instance again
final Random randomInstanceCopy = Random.from(randomInstance);
assertSame(randomInstance, randomInstanceCopy);
}
private int delegationCount;
private class RandomGen implements RandomGenerator {
@Override
public boolean isDeprecated() {
delegationCount += 1;
return RandomGenerator.super.isDeprecated();
}
@Override
public float nextFloat(float bound) {
delegationCount += 1;
return RandomGenerator.super.nextFloat(bound);
}
@Override
public double nextDouble(double bound) {
delegationCount += 1;
return RandomGenerator.super.nextDouble(bound);
}
@Override
public long nextLong() {
return 0;
}
}
/*
* Test whether calls to methods inherited from RandomGenerator
* are delegated to the instance returned by from().
* This is not a complete coverage, but simulates the reproducer
* in issue JDK-8288596
*/
public void testRandomFrom() {
delegationCount = 0;
var r = Random.from(new RandomGen());
r.isDeprecated();
r.nextFloat(1_000.0f);
r.nextFloat(); // not implemented in RandomGen, does not count
r.nextDouble(1_000.0);
r.nextDouble(); // not implemented in RandomGen, does not count
assertEquals(delegationCount, 3);
}
}
¤ Dauer der Verarbeitung: 0.4 Sekunden
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