@Override
  public final void postSetUp() throws Exception {
    disconnectAllFromDS();
    Wait.pause(2000);
    final Host host = Host.getHost(0);
    server1 = host.getVM(0);
    server2 = host.getVM(1);
    // start servers first
    PORT1 = server1.invoke(InterestListRecoveryDUnitTest::createServerCache);
    PORT2 = server2.invoke(InterestListRecoveryDUnitTest::createServerCache);

    org.apache.geode.test.dunit.LogWriterUtils.getLogWriter()
        .info("server1 port is " + PORT1);
    org.apache.geode.test.dunit.LogWriterUtils.getLogWriter()
        .info("server2 port is " + PORT2);

    createClientCache(NetworkUtils.getServerHostName(host), PORT1, PORT2);
  }
Test Scenario :

one client(c1) two servers(s1,s2) s1,s2 ----> available c1: register k1,k2,k3,k4,k5 s1 ---->
unavailable // fail over should happen to server s2 see all keys k1,k2,k3,k4,k5 are registered on
s2 c1: unregister k1,k2,k3 see interest list on s1 contains only s4, s5 s2 ----> unavaliable //
fail over should to s1 with intrest list s4,s5 see only k4 and k5 are registerd on s1
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/InterestListRecoveryDUnitTest.java