class_docstr: Unit tests for the Voronoi cells function.
class_docstr_tok: ["Unit","tests","for","the","Voronoi","cells","function","."]
docstr: Tests that a graph with isolated nodes has all isolates in
  one block of the partition.
docstr_tok: ["Tests","that","a","graph","with","isolated","nodes","has","all","isolates","in","one","block","of","the","partition","."]
code: def test_isolates(self):
      """Tests that a graph with isolated nodes has all isolates in
      one block of the partition.
  
      """
      G = nx.empty_graph(5)
      cells = nx.voronoi_cells(G, {0, 2, 4})
      expected = {0: {0}, 2: {2}, 4: {4}, "unreachable": {1, 3}}
      assert expected == cells
  
file_path: networkx/networkx/algorithms/tests/test_voronoi.py
imports: import networkx
  from networkx.utils import pairwise
label_desc: Use image node_id 1 for calling the TestVoronoiCells obj's underlying member method code with example usage: obj.test_isolates() without return types