Merge "Fix flaky IpPrefixTest."

import android.net.IpPrefix;

import android.os.Parcel;

import static android.test.MoreAsserts.assertNotEqual;

import android.test.suitebuilder.annotation.SmallTest;

import static org.junit.Assert.assertArrayEquals;

import java.net.InetAddress;

import java.util.Random;

import junit.framework.TestCase;

import static android.test.MoreAsserts.assertNotEqual;

import static org.junit.Assert.assertArrayEquals;

import static org.junit.Assert.assertEquals;

public class IpPrefixTest extends TestCase {

    @SmallTest

    public void testHashCode() {

        IpPrefix p;

        int oldCode = -1;

        IpPrefix p = new IpPrefix(new byte[4], 0);

        Random random = new Random();

        for (int i = 0; i < 100; i++) {

            final IpPrefix oldP = p;

            if (random.nextBoolean()) {

                // IPv4.

                byte[] b = new byte[4];

                random.nextBytes(b);

                p = new IpPrefix(b, random.nextInt(33));

                assertNotEqual(oldCode, p.hashCode());

                oldCode = p.hashCode();

            } else {

                // IPv6.

                byte[] b = new byte[16];

                random.nextBytes(b);

                p = new IpPrefix(b, random.nextInt(129));

                assertNotEqual(oldCode, p.hashCode());

                oldCode = p.hashCode();

            }

            if (p.equals(oldP)) {

              assertEquals(p.hashCode(), oldP.hashCode());

            }

            if (p.hashCode() != oldP.hashCode()) {

              assertNotEqual(p, oldP);

            }

        }

    }

    @SmallTest

    public void testHashCodeIsNotConstant() {

        IpPrefix[] prefixes = {

            new IpPrefix("2001:db8:f00::ace:d00d/127"),

            new IpPrefix("192.0.2.0/23"),

            new IpPrefix("::/0"),

            new IpPrefix("0.0.0.0/0"),

        };

        for (int i = 0; i < prefixes.length; i++) {

          for (int j = i + 1; j < prefixes.length; j++) {

            assertNotEqual(prefixes[i].hashCode(), prefixes[j].hashCode());

          }

        }

    }