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

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

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

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

    client.invoke(() -> ClientToServerDeltaDUnitTest.checkTodeltaCounter(2));

    server.invoke(ClientToServerDeltaDUnitTest::checkDeltaFeatureNotUsed);

    server2.invoke(() -> ClientToServerDeltaDUnitTest.checkTodeltaCounter(0));
    server2.invoke(ClientToServerDeltaDUnitTest::checkFromdeltaCounter);
  }
This test does the following for single key:<br>
1)Verifies that To delta called on client should be equal to fromDeltaCounter on datastore <br>
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientToServerDeltaDUnitTest.java