CS代写 package comp1110.exam;

package comp1110.exam;

import org.junit.BeforeClass;
import org.junit.FixMethodOrder;

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import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.Timeout;
import org.junit.runners.MethodSorters;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Random;
import java.util.Set;

import static junit.framework.TestCase.assertFalse;
import static org.junit.Assert.assertTrue;

@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class Q5PackageSpecificationTest {
public Timeout globalTimeout = Timeout.millis(1000);

public static final int HASH_ITERATIONS = 100;

static Q5PackageSpecification[] packages = new Q5PackageSpecification[200 * HASH_ITERATIONS];

public void testHashCodeDeterministic() {
checkNotObjectHashCode();
Random r = new Random(0);
for (Q5PackageSpecification pack : packages) {
int hash = pack.hashCode();
for (int i = 0; i < 10; i++) { int hash2 = pack.hashCode(); assertTrue("package " + pack + " returned different values for hashCode(): " + hash + ", " + hash2, hash == hash2); public void testAllFields() { checkNotObjectHashCode(); Q5PackageSpecification pack1 = new Q5PackageSpecification("curl", 6, 2); Q5PackageSpecification pack2 = new Q5PackageSpecification("curl", 6, 3); testDifferent(pack1, pack2); testDifferent(pack1, pack2); pack2 = new Q5PackageSpecification("curl", 2, 6); testDifferent(pack1, pack2); testDifferent(pack1, pack2); pack2 = new Q5PackageSpecification("curl", 7, 2); testDifferent(pack1, pack2); testDifferent(pack1, pack2); pack2 = new Q5PackageSpecification("reap", 6, 2); testDifferent(pack1, pack2); testDifferent(pack1, pack2); pack2 = new Q5PackageSpecification("lurc", 6, 2); testDifferent(pack1, pack2); testDifferent(pack1, pack2); public void testEquals() { Q5PackageSpecification pack1 = new Q5PackageSpecification("curl", 6, 2); assertTrue("pack1.equals(pack1) returned false", pack1.equals(pack1)); Q5PackageSpecification pack2 = new Q5PackageSpecification("curl", 6, 3); assertFalse("packages " + pack1 + " and " + pack2 + " are not equal, but pack1.equals(pack2) returned true", pack1.equals(pack2)); pack2.minorVersionNumber = 2; pack2.majorVersionNumber = 7; assertFalse("packages " + pack1 + " and " + pack2 + " are not equal, but pack1.equals(pack2) returned true", pack1.equals(pack2)); pack2.majorVersionNumber = 6; pack2.name = "crul"; assertFalse("packages " + pack1 + " and " + pack2 + " are not equal, but pack1.equals(pack2) returned true", pack1.equals(pack2)); pack2.name = null; assertFalse("packages " + pack1 + " and " + pack2 + " are not equal, but pack1.equals(pack2) returned true", pack1.equals(pack2)); pack1.name = null; assertTrue("packages " + pack1 + " and " + pack2 + " are equal, but pack1.equals(pack2) returned false", pack1.equals(pack2)); pack2.name = "curl"; assertFalse("packages " + pack1 + " and " + pack2 + " are not equal, but pack1.equals(pack2) returned true", pack1.equals(pack2)); pack1.name = "curl"; assertTrue("packages " + pack1 + " and " + pack2 + " are equal, but pack1.equals(pack2) returned false", pack1.equals(pack2)); public void testUniformA() { checkNotObjectHashCode(); // chiSquared critical value (DOF=10-1, prob=0.999) ~= 27.88 testUniformity(10, 27.88); public void testUniformB() { checkNotObjectHashCode(); // chiSquared critical value (DOF=50-1, prob=0.999) ~= 85.35 testUniformity(50, 85.35); private void testUniformity(int buckets, double chiSqCriticalValue) { Random r = new Random(); int[] count = new int[buckets]; int samples = buckets * HASH_ITERATIONS; for (int i = 0; i < samples; i++) { Q5PackageSpecification pack = packages[r.nextInt(packages.length)]; int h = Math.abs(pack.hashCode()) % buckets; count[h]++; double chiSq = chiSquaredUniform(samples, count); assertTrue("Distribution of hash function doesn't appear to be uniform over " + buckets + " buckets (chi squared value of " + chiSq + ").\nExpected " + samples / buckets + " elements per bucket, but got " + Arrays.toString(count), chiSq < chiSqCriticalValue); private void checkNotObjectHashCode() { Random r = new Random(); int range = 39; Set myBuckets[] = new Set[range];
Set defaultBuckets[] = new Set[range];
for (int i = 0; i < range; i++) { myBuckets[i] = new HashSet<>();
defaultBuckets[i] = new HashSet<>();

for (int i = 0; i < 98 * HASH_ITERATIONS; i++) { Q5PackageSpecification pack = packages[r.nextInt(packages.length)]; int m = Math.abs(pack.hashCode()) % range; myBuckets[m].add(pack); int n = Math.abs(pack.passThroughHash()) % range; defaultBuckets[n].add(pack); for (Set myBucket : myBuckets) {
for (Set defaultBucket : defaultBuckets) {
assertFalse(“It looks like you’re using Object.hashCode()!”, myBucket.equals(defaultBucket));

private void testDifferent(Q5PackageSpecification pack1, Q5PackageSpecification pack2) {
int hash1 = pack1.hashCode();
int hash2 = pack2.hashCode();
assertTrue(“packages ” + pack1 + ” and ” + pack2 + ” returned same hashCode(): ” + hash1 + “, ” + hash2, hash1 != hash2);

@BeforeClass
public static void generatePackages() {
Random r = new Random(0);
for (int i = 0; i < packages.length; i++) { char[] randomName = new char[r.nextInt(5) + 3]; for (int c = 0; c < randomName.length; c++) { if (c > 0 && r.nextInt(10) < 1) { randomName[c] = (char) (r.nextInt(123 - 40) + '-'); randomName[c] = (char) (r.nextInt(123 - 97) + 'a'); packages[i] = new Q5PackageSpecification(String.valueOf(randomName), r.nextInt(10), r.nextInt(100)); System.out.println(packages[i]); private static double chiSquaredUniform(int samples, int[] counts) { double uniformProb = 1.0 / counts.length; double total = 0; for (int i = 0; i < counts.length; i++) { double mi = ((double) samples) * uniformProb; total += ((double) counts[i] - mi) * ((double) counts[i] - mi) / mi; return total; 程序代写 CS代考 加微信: powcoder QQ: 1823890830 Email: powcoder@163.com