fixed a little problem with the checkNullNode method

Signed-off-by: Maximilian Berghoff <Maximilian.Berghoff@onit-gmbh.de>
little comment refactoring
using the oneByoneTest again
try to get the way to construct a objects with the property in the xml

Signed-off-by: Maximilian Berghoff <Maximilian.Berghoff@onit-gmbh.de>