public void TestNullDatasourceHandeler()
{
IDataSource dataSource = new DataSource.DataSource(null);
IDecisionService service = new DecisionService(dataSource);
Assert.Throws <NodeNotFoundException>(() => service.GetFirstQuestion());
Assert.Throws <NodeNotFoundException>(() => service.GetFirstNode());
Assert.Null(service.GetFullTree());
//Assert.(3, _service.GetTreeMaxpath());
}
