@Test
  public void testConflationUpdate() throws Exception {

    server1.invoke(putFromServer(KEY1, VALUE1));
    server1.invoke(putFromServer(KEY1, VALUE2));
    server1.invoke(putFromServer(KEY1, VALUE3));
    server1.invoke(putFromServer(KEY1, VALUE1));
    server1.invoke(putFromServer(KEY1, VALUE2));
    server1.invoke(putFromServer(KEY1, VALUE3));
    server1.invoke(putFromServer(KEY1, VALUE1));
    server1.invoke(putFromServer(KEY1, VALUE2));
    server1.invoke(putFromServer(KEY1, VALUE3));
    server1.invoke(putFromServer(LAST_KEY, LAST_VALUE));
    expectedNoEvents = 2;
    client1.invoke(checkNoEvents(expectedNoEvents));

  }
In this test do create , then update & update. The client should receive 2 callbacks , one for
create & one for the last update.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ha/HAConflationDistributedTest.java