code: def test_hamiltonian_cycle():
      """Tests that :func:`networkx.tournament.hamiltonian_path`
      returns a Hamiltonian cycle when provided a strongly connected
      tournament.
  
      """
      G = DiGraph()
      G.add_edges_from([(0, 1), (1, 2), (2, 3), (3, 0), (1, 3), (0, 2)])
      path = hamiltonian_path(G)
      assert len(path) == 4
      assert all(v in G[u] for u, v in zip(path, path[1:]))
      assert path[0] in G[path[-1]]
  
imports: from itertools import combinations
  import pytest
  from networkx import DiGraph
  from networkx.algorithms.tournament import hamiltonian_path, index_satisfying, is_reachable, is_strongly_connected, is_tournament, random_tournament, score_sequence, tournament_matrix
label_desc: Use image node_id 13 for calling a global function with example usage: test_hamiltonian_cycle() without return types