@Test
  public void testEmptyClientAsFeederToServer() {
    Integer PORT1 = server
        .invoke(() -> ClientToServerDeltaDUnitTest.createServerCache(Boolean.FALSE, Boolean.FALSE));

    server2
        .invoke(() -> ClientToServerDeltaDUnitTest.createServerCache(Boolean.FALSE, Boolean.FALSE));

    client.invoke(() -> ClientToServerDeltaDUnitTest.createClientCache(
        NetworkUtils.getServerHostName(server.getHost()), new Integer(PORT1), Boolean.FALSE,
        Boolean.TRUE, Boolean.FALSE));

    /*
     * server2.invoke(() -> ClientToServerDeltaDUnitTest.setFirstSecondUpdate( putDelta[0],
     * (Integer)putDelta[2] ));
     */

    client.invoke(() -> ClientToServerDeltaDUnitTest.putDelta(KEY1));

    client.invoke(() -> ClientToServerDeltaDUnitTest.checkTodeltaCounter(2));
    server.invoke(ClientToServerDeltaDUnitTest::checkFromdeltaCounter);
    server.invoke(() -> ClientToServerDeltaDUnitTest.checkTodeltaCounter(0));
    server2.invoke(ClientToServerDeltaDUnitTest::checkFromdeltaCounter);
    server2.invoke(() -> ClientToServerDeltaDUnitTest.checkTodeltaCounter(0));
  }
This test does the following for single key:<br>
1)Verifies that cacheless client calls toDelta <br>
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientToServerDeltaDUnitTest.java