public static void verifyDeltaReceived() {
    assertTrue(
        "Expected 1 fromDelta() invokation but was " + DeltaTestImpl.getFromDeltaInvokations(),
        DeltaTestImpl.getFromDeltaInvokations() == 1);
  }
This test ensures that a server sends delta bytes to a client even if that client is not
interested in that event but is getting the event only because the event satisfies a CQ which
the client has registered with the server.
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientToServerDeltaDUnitTest.java