@Override
      public Object call() {
        System.out.println("[testGetConnectedClients] create bridge client");
        properties = new Properties();
        properties.setProperty(MCAST_PORT, "0");
        properties.setProperty(LOCATORS, "");
        getSystem(properties);
        AttributesFactory factory = new AttributesFactory();
        factory.setScope(Scope.LOCAL);
        Pool p = ClientServerTestCase.configureConnectionPool(factory,
            NetworkUtils.getServerHostName(host), ports, true, -1, -1, null);
        createRegion(name, factory.create());
        assertNotNull(getRootRegion().getSubregion(name));
        assertTrue(p.getServers().size() > 0);
        return getMemberId();
      }
Starts up server in controller vm and 4 clients, then calls and tests
ClientMembership.getConnectedClients().
geode-core/src/distributedTest/java/org/apache/geode/cache30/ClientMembershipDUnitTest.java