Deflake and fix testIpClientClearingIpAddressState. am: 2ed62241

import com.android.networkstack.apishim.ConstantsShim;

import com.android.networkstack.apishim.ShimUtils;

import com.android.networkstack.arp.ArpPacket;

import com.android.server.NetworkObserver;

import com.android.server.NetworkObserverRegistry;

import com.android.server.NetworkStackService.NetworkStackServiceManager;

import com.android.server.connectivity.ipmemorystore.IpMemoryStoreService;

import java.util.List;

import java.util.Objects;

import java.util.Random;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.TimeUnit;

/**

 * Tests for IpClient.

    @Spy private INetd mNetd;

    private String mIfaceName;

    private NetworkObserverRegistry mNetworkObserverRegistry;

    private HandlerThread mPacketReaderThread;

    private Handler mHandler;

    private TapPacketReader mPacketReader;

        when(mContext.getSystemService(eq(Context.NETD_SERVICE))).thenReturn(netdIBinder);

        assertNotNull(mNetd);

        final NetworkObserverRegistry reg = new NetworkObserverRegistry();

        reg.register(mNetd);

        mIpc = new IpClient(mContext, mIfaceName, mCb, reg, mNetworkStackServiceManager,

                mDependencies);

        mNetworkObserverRegistry = new NetworkObserverRegistry();

        mNetworkObserverRegistry.register(mNetd);

        mIpc = new IpClient(mContext, mIfaceName, mCb, mNetworkObserverRegistry,

                mNetworkStackServiceManager, mDependencies);

    }

    private void expectAlarmCancelled(InOrder inOrder, OnAlarmListener listener) {

        fail("No router solicitation received on interface within timeout");

    }

    private void sendBasicRouterAdvertisement(boolean waitForRs) throws Exception {

        final String dnsServer = "2001:4860:4860::64";

        final ByteBuffer pio = buildPioOption(3600, 1800, "2001:db8:1::/64");

        ByteBuffer rdnss = buildRdnssOption(3600, dnsServer);

        ByteBuffer ra = buildRaPacket(pio, rdnss);

        if (waitForRs) {

            waitForRouterSolicitation();

        }

        mPacketReader.sendResponse(ra);

    }

    // TODO: move this and the following method to a common location and use them in ApfTest.

    private static ByteBuffer buildPioOption(int valid, int preferred, String prefixString)

            throws Exception {

        expectNat64PrefixUpdate(inOrder, null);

    }

    private void addIpAddressAndWaitForIt(final String iface) throws Exception {

        final CountDownLatch latch = new CountDownLatch(1);

        final String addr1 = "192.0.2.99";

        final String addr2 = "192.0.2.3";

        final int prefixLength = 26;

        // Add two IPv4 addresses to the specified interface, and proceed when the NetworkObserver

        // has seen the second one. This ensures that every other NetworkObserver registered with

        // mNetworkObserverRegistry - in particular, IpClient's - has seen the addition of the first

        // address.

        final LinkAddress trigger = new LinkAddress(addr2 + "/" + prefixLength);

        NetworkObserver observer = new NetworkObserver() {

            @Override

            public void onInterfaceAddressUpdated(LinkAddress address, String ifName) {

                if (ifName.equals(iface) && address.isSameAddressAs(trigger)) {

                    latch.countDown();

                }

            }

        };

        mNetworkObserverRegistry.registerObserverForNonblockingCallback(observer);

        try {

            mNetd.interfaceAddAddress(iface, addr1, prefixLength);

            mNetd.interfaceAddAddress(iface, addr2, prefixLength);

            assertTrue("Trigger IP address " + addr2 + " not seen after " + TEST_TIMEOUT_MS + "ms",

                    latch.await(TEST_TIMEOUT_MS, TimeUnit.MILLISECONDS));

        } finally {

            mNetworkObserverRegistry.unregisterObserver(observer);

        }

        // Wait for IpClient to process the addition of the address.

        HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

    }

    @Test

    public void testIpClientClearingIpAddressState() throws Exception {

        final long currentTime = System.currentTimeMillis();

        // Pretend that something else (e.g., Tethering) used the interface and left an IP address

        // configured on it. When IpClient starts, it must clear this address before proceeding.

        // TODO: test IPv6 instead, since the DHCP client will remove this address by replacing it

        // with the new address.

        mNetd.interfaceAddAddress(mIfaceName, "192.0.2.99", 26);

        // The address must be noticed before startProvisioning is called, or IpClient will

        // immediately declare provisioning success due to the presence of an IPv4 address.

        // The address must be IPv4 because IpClient clears IPv6 addresses on startup.

        //

        // TODO: once IpClient gets IP addresses directly from netlink instead of from netd, it

        // may be sufficient to call waitForIdle to see if IpClient has seen the address.

        addIpAddressAndWaitForIt(mIfaceName);

        // start IpClient again and should enter Clearing State and wait for the message from kernel

        performDhcpHandshake(true /* isSuccessLease */, TEST_LEASE_DURATION_S,

                true /* isDhcpLeaseCacheEnabled */, false /* shouldReplyRapidCommitAck */,

                TEST_DEFAULT_MTU, false /* isDhcpIpConflictDetectEnabled */);

        disableRouterSolicitationDelay();

        ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()

                .withoutIpReachabilityMonitor()

                .build();

        mIpc.startProvisioning(config);

        sendBasicRouterAdvertisement(true /*waitForRs*/);

        // Check that the IPv4 addresses configured earlier are not in LinkProperties...

        ArgumentCaptor<LinkProperties> captor = ArgumentCaptor.forClass(LinkProperties.class);

        verify(mCb, timeout(TEST_TIMEOUT_MS)).onProvisioningSuccess(captor.capture());

        assertFalse(captor.getValue().hasIpv4Address());

        // ... or configured on the interface.

        InterfaceConfigurationParcel cfg = mNetd.interfaceGetCfg(mIfaceName);

        assertEquals("0.0.0.0", cfg.ipv4Addr);

    }

    @Test