code: def test_empty(self):
      G = nx.Graph()
      G.add_node(1)
      M = nx.to_scipy_sparse_array(G)
      np.testing.assert_equal(M.toarray(), np.array([[0]]))
  
imports: import pytest
  import networkx
  from networkx.generators.classic import barbell_graph, cycle_graph, path_graph
  from networkx.utils import graphs_equal
label_desc: Use image node_id 15 for calling the TestConvertScipy obj's underlying member method code with example usage: obj.test_empty() without return types