DataIterator i = Builder.create(o, null, order).dataIterator();
DataElement e = i.next();
if (order == IterationOrder.PRE_ORDER)
{
assertEquals(e.level(), 0, "preorder traversal of " + input + " started with level " + e.level());
}
else
{
assertEquals(e.level(), 2, "postorder traversal of " + input + " started with level " + e.level());
}