private void determineAndVerfiyNonRedundantServers(Collection redundantServers) {
    if (!redundantServers.contains(SERVER1)) {
      server1.invoke(DurableClientReconnectDUnitTest::verifyNoDurableClientOnServer);
    }
    if (!redundantServers.contains(SERVER2)) {
      server2.invoke(DurableClientReconnectDUnitTest::verifyNoDurableClientOnServer);
    }
    if (!redundantServers.contains(SERVER3)) {
      server3.invoke(DurableClientReconnectDUnitTest::verifyNoDurableClientOnServer);
    }
    if (!redundantServers.contains(SERVER4)) {
      server4.invoke(DurableClientReconnectDUnitTest::verifyNoDurableClientOnServer);
    }
  }
This test checks a problem found in bug 39332 1. Durable client disconnects 2. Durable client
comes back, creates a create to server connection but not a queue connection 3. Durable client
disconnects again 4. Durable client connects 5. Eventually, all of the durable clients
connections are closed because the durable expiration timer task created in step 1 is never
cancelled.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/DurableClientReconnectDUnitTest.java