// d
// / \
// b f
// / \
// a g
SimpleNode a = new SimpleNode('a', null, null);
SimpleNode b = new SimpleNode('b', a, null);
SimpleNode g = new SimpleNode('g', null, null);
SimpleNode f = new SimpleNode('f', null, g);
SimpleNode d = new SimpleNode('d', b, f);
BstPathFactory<SimpleNode, BstInOrderPath<SimpleNode>> factory =
BstInOrderPath.inOrderFactory();
BstInOrderPath<SimpleNode> path = extension(factory, d, RIGHT, RIGHT);
ASSERT.that(pathToList(path)).hasContentsInOrder(g, f, d);
path = testPrevPathIs(path, f, d);