return viewer.postOrderTraversal(root);
      }
    },
    BREADTH_FIRST {
      @Override
      <T> Iterable<T> view(T root, TreeTraverser<T> viewer) {
        return viewer.breadthFirstTraversal(root);
      }
    };

    abstract <T> Iterable<T> view(T root, TreeTraverser<T> viewer);
  }

  private Iterable<BinaryNode> view;

  @Param Topology topology;

  }

  public void testPostOrder() {
    assertThat(iterationOrder(ADAPTER.postOrderTraversal(h))).isEqualTo("abcdefgh");
  }

  public void testBreadthOrder() {
    assertThat(iterationOrder(ADAPTER.breadthFirstTraversal(h))).isEqualTo("hdegabcf");
  }

  public void testUsing() {
    assertThat(iterationOrder(ADAPTER_USING_USING.preOrderTraversal(h))).isEqualTo("hdabcegf");
  }

  @J2ktIncompatible

   *
   * @deprecated Use {@link com.google.common.graph.Traverser#breadthFirst} instead, which has the
   *     same behavior.
   */
  @Deprecated
  public final FluentIterable<T> breadthFirstTraversal(final T root) {
    checkNotNull(root);
    return new FluentIterable<T>() {
      @Override
      public UnmodifiableIterator<T> iterator() {
        return new BreadthFirstIterator(root);
      }

        return viewer.postOrderTraversal(root);
      }
    },
    BREADTH_FIRST {
      @Override
      <T> Iterable<T> view(T root, TreeTraverser<T> viewer) {
        return viewer.breadthFirstTraversal(root);
      }
    };

    abstract <T> Iterable<T> view(T root, TreeTraverser<T> viewer);
  }

  private Iterable<BinaryNode> view;

  @Param Topology topology;