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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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package org.apache.cassandra.gms;

import java.util.Collections;
import java.util.concurrent.atomic.AtomicBoolean;

import org.junit.After;
import org.junit.BeforeClass;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.Keyspace;
import org.apache.cassandra.exceptions.ConfigurationException;
import org.apache.cassandra.locator.IEndpointSnitch;
import org.apache.cassandra.locator.PropertyFileSnitch;
import org.apache.cassandra.net.MessageIn;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.net.MockMessagingService;
import org.apache.cassandra.net.MockMessagingSpy;
import org.apache.cassandra.service.StorageService;

import static org.apache.cassandra.net.MockMessagingService.verb;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class ShadowRoundTest
{
    private static final Logger logger = LoggerFactory.getLogger(ShadowRoundTest.class);

    @BeforeClass
    public static void setUp() throws ConfigurationException
    {
        System.setProperty("cassandra.config", "cassandra-seeds.yaml");

        DatabaseDescriptor.daemonInitialization();
        IEndpointSnitch snitch = new PropertyFileSnitch();
        DatabaseDescriptor.setEndpointSnitch(snitch);
        Keyspace.setInitialized();
    }

    @After
    public void cleanup()
    {
        MockMessagingService.cleanup();
    }

    @Test
    public void testDelayedResponse()
    {
        Gossiper.instance.buildSeedsList();
        int noOfSeeds = Gossiper.instance.seeds.size();

        final AtomicBoolean ackSend = new AtomicBoolean(false);
        MockMessagingSpy spySyn = MockMessagingService.when(verb(MessagingService.Verb.GOSSIP_DIGEST_SYN))
                .respondN((msgOut, to) ->
                {
                    // ACK once to finish shadow round, then busy-spin until gossiper has been enabled
                    // and then reply with remaining ACKs from other seeds
                    if (!ackSend.compareAndSet(false, true))
                    {
                        while (!Gossiper.instance.isEnabled()) ;
                    }

                    HeartBeatState hb = new HeartBeatState(123, 456);
                    EndpointState state = new EndpointState(hb);
                    GossipDigestAck payload = new GossipDigestAck(
                            Collections.singletonList(new GossipDigest(to, hb.getGeneration(), hb.getHeartBeatVersion())),
                            Collections.singletonMap(to, state));

                    logger.debug("Simulating digest ACK reply");
                    return MessageIn.create(to, payload, Collections.emptyMap(), MessagingService.Verb.GOSSIP_DIGEST_ACK, MessagingService.current_version);
                }, noOfSeeds);

        // GossipDigestAckVerbHandler will send ack2 for each ack received (after the shadow round)
        MockMessagingSpy spyAck2 = MockMessagingService.when(verb(MessagingService.Verb.GOSSIP_DIGEST_ACK2)).dontReply();

        // Migration request messages should not be emitted during shadow round
        MockMessagingSpy spyMigrationReq = MockMessagingService.when(verb(MessagingService.Verb.MIGRATION_REQUEST)).dontReply();

        try
        {
            StorageService.instance.initServer();
        }
        catch (Exception e)
        {
            assertEquals("Unable to contact any seeds!", e.getMessage());
        }

        // we expect one SYN for each seed during shadow round + additional SYNs after gossiper has been enabled
        assertTrue(spySyn.messagesIntercepted > noOfSeeds);

        // we don't expect to emit any GOSSIP_DIGEST_ACK2 or MIGRATION_REQUEST messages
        assertEquals(0, spyAck2.messagesIntercepted);
        assertEquals(0, spyMigrationReq.messagesIntercepted);
    }
}