public void testTraversePreOrder() {
Iterator<BinaryInterval> iterator = lst.preorderIterator();
int i = 0;
while (iterator.hasNext()) {
Interval node = iterator.next();
IntervalImpl ref = preOrder[i++];
if (!ref.equals(node)) {
System.err.println(ref + " != " + node);
fail("node mismatch");
} else {
System.out.println(ref + " == " + node);
}