class_docstr: Unit tests for the
  :func:`~networkx.algorithms.matching.maximal_matching`.
code: def test_single_edge_matching(self):
      # In the star graph, any maximal matching has just one edge.
      G = nx.star_graph(5)
      matching = nx.maximal_matching(G)
      assert 1 == len(matching)
      assert nx.is_maximal_matching(G, matching)
  
imports: import math
  from itertools import permutations
  from pytest import raises
  import networkx
  from networkx.algorithms.matching import matching_dict_to_set
  from networkx.utils import edges_equal
label_desc: Use image node_id 2 for calling the TestMaximalMatching obj's underlying member method code with example usage: obj.test_single_edge_matching() without return types