@Test
  public void duplicateSeqIdLesserThanCurrentSeqIdBeingIgnored() throws Exception {
    int port3 = getRandomAvailableTCPPort();
    addCacheServer(port3, 10000);

    PoolFactory poolFactory = PoolManager.createFactory();
    poolFactory.addServer("localhost", port3);
    poolFactory.setSubscriptionEnabled(true);
    poolFactory.setSubscriptionRedundancy(-1);
    poolFactory.setSubscriptionMessageTrackingTimeout(100000);
    proxy = (PoolImpl) poolFactory.create("clientPool");

    EventID eventId1 = new EventID(new byte[0], 1, 5);
    assertThat(proxy.verifyIfDuplicate(eventId1))
        .describedAs("eventId1 can never be duplicate, it is being created for the first time!")
        .isFalse();

    EventID eventId2 = new EventID(new byte[0], 1, 2);

    assertThat(proxy.verifyIfDuplicate(eventId2))
        .describedAs("eventId2 should be duplicate, seqId is less than highest (5)")
        .isTrue();

    EventID eventId3 = new EventID(new byte[0], 1, 3);

    assertThat(proxy.verifyIfDuplicate(eventId3))
        .describedAs("eventId3 should be duplicate, seqId is less than highest (5)")
        .isTrue();

    assertThat(!proxy.getThreadIdToSequenceIdMap().isEmpty()).isTrue();
    proxy.destroy();
  }
Tests the functionality of operations of AbstractConnectionProxy & its derived classes.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/tier/sockets/ConnectionProxyIntegrationTest.java