docstr: Tests that A* accommodates nodes that are not orderable.
  
  For more information, see issue #554.
docstr_tok: ["Tests","that","A","*","accommodates","nodes","that","are","not","orderable",".","For","more","information",",","see","issue","#","554","."]
code: def test_unorderable_nodes(self):
      """Tests that A* accommodates nodes that are not orderable.
  
      For more information, see issue #554.
  
      """
      # Create the cycle graph on four nodes, with nodes represented
      # as (unorderable) Python objects.
      nodes = [object() for n in range(4)]
      G = nx.Graph()
      G.add_edges_from(pairwise(nodes, cyclic=True))
      path = nx.astar_path(G, nodes[0], nodes[2])
      assert len(path) == 3
  
imports: import pytest
  import networkx
  from networkx.utils import pairwise
label_desc: Use image node_id 19 for calling the TestAStar obj's underlying member method code with example usage: obj.test_unorderable_nodes() without return types