assertEqualCharNodes(traverser.depthFirstPostOrder(charactersOf("acdb")), "dbca");
    assertEqualCharNodes(traverser.depthFirstPostOrder(charactersOf("db")), "db");
  }

  @Test
  public void forGraph_depthFirstPostOrder_multigraph() {
    Traverser<Character> traverser = Traverser.forGraph(MULTI_GRAPH);
    assertEqualCharNodes(traverser.depthFirstPostOrder('a'), "dbca");
    assertEqualCharNodes(traverser.depthFirstPostOrder('b'), "db");