private static void verifyNoCacheClientProxyOnServer() {
    try {
      Cache cache = new ClientServerMiscDUnitTestBase().getCache();
      assertEquals("More than one BridgeServer", 1, cache.getCacheServers().size());
      CacheServerImpl cacheServer = (CacheServerImpl) cache.getCacheServers().iterator().next();
      assertNotNull(cacheServer);
      assertNotNull(cacheServer.getAcceptor());
      final CacheClientNotifier ccn = cacheServer.getAcceptor().getCacheClientNotifier();

      assertNotNull(ccn);
      await()
          .until(() -> ccn.getClientProxies().size() == 0);
    } catch (Exception ex) {
      System.out.println("The size of the client proxies != 0");
      OSProcess.printStacks(0);
      throw ex;
    }
  }
bug 35380: Cycling a DistributedSystem with an initialized pool causes interest registration
NPE

Test Scenario:

Create a DistributedSystem (DS1). Create a pool, initialize (creates a proxy with DS1 memberid)
Disconnect DS1. Create a DistributedSystem (DS2). Create a Region with pool, it attempts to
register interest using DS2 memberid, gets NPE.
geode-dunit/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientServerMiscDUnitTestBase.java