@Test
  public void testEmptyTX() {
    Host host = Host.getHost(0);
    VM datastore = host.getVM(0);
    VM client = host.getVM(1);

    int port = createRegionsAndStartServer(datastore, false);
    createClientRegion(client, port, false);

    client.invoke(new SerializableCallable<Object>() {
      @Override
      public Object call() {
        Region<CustId, Customer> pr = getGemfireCache().getRegion(CUSTOMER);
        getCache().getCacheTransactionManager().begin();
        pr.size();
        getCache().getCacheTransactionManager().commit();
        return null;
      }
    });
  }
test has a client, two accessors and a datastore pool connects to two accessors. we then close
the server in first accessor and verify failover
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ClientServerTransactionDUnitTest.java