@Test
  public void testToDataFromLowerVersionToHigher() throws Exception {
    DataOutputStream dos =
        new VersionedDataOutputStream(new DataOutputStream(baos), KnownVersion.GEODE_1_5_0);
    InternalDataSerializer.writeDSFID(msg, dos);
    assertTrue(toDataCalled);
  }
Test if correct toData/toDataXXX is called when changes are made to the TestMessage
geode-core/src/distributedTest/java/org/apache/geode/internal/BackwardCompatibilitySerializationDUnitTest.java