public void Should_write_the_collections()
        {
            var joinedSubclassMapping = new JoinedSubclassMapping();
            joinedSubclassMapping.AddCollection(new BagMapping());

            _mocker.Get<IHbmWriter<ICollectionMapping>>()
                .Expect(x => x.Write(joinedSubclassMapping.Collections.First())).Return(new HbmBag());

            _subclassWriter.VerifyXml(joinedSubclassMapping)
                .Element("bag").Exists();
        }