// throws jjtraveler.VisitFailure
public virtual void testBreadthFirst()
{
Identity id = new Identity();
Logger expected = new Logger(id, new IVisitable[]{n4, n3, n2, n0, n1} );
BreadthFirst bf = new BreadthFirst( logVisitor(id) );
IVisitable resultNode = bf.visit(n4);
Assertion.AssertEquals(expected, logger);
Assertion.AssertEquals(resultNode, n4);
}