class_docstr: Unit tests for the Voronoi cells function.
class_docstr_tok: ["Unit","tests","for","the","Voronoi","cells","function","."]
code: def test_directed_unweighted(self):
      # This is the singly-linked directed cycle graph on six nodes.
      G = nx.DiGraph(pairwise(range(6), cyclic=True))
      cells = nx.voronoi_cells(G, {0, 3})
      expected = {0: {0, 1, 2}, 3: {3, 4, 5}}
      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 3 for calling the TestVoronoiCells obj's underlying member method code with example usage: obj.test_directed_unweighted() without return types