class_docstr: Unit tests for the :meth:`MultiGraph.edge_subgraph` method.
class_docstr_tok: ["Unit","tests","for","the",":","meth",":","`","MultiGraph.edge_subgraph","`","method","."]
docstr: Tests that adding a node to the original graph does not
  affect the nodes of the subgraph.
docstr_tok: ["Tests","that","adding","a","node","to","the","original","graph","does","not","affect","the","nodes","of","the","subgraph","."]
code: def test_add_node(self):
      """Tests that adding a node to the original graph does not
      affect the nodes of the subgraph.
  
      """
      self.G.add_node(5)
      assert [0, 1, 3, 4] == sorted(self.H.nodes())
  
imports: from collections import UserDict
  import pytest
  import networkx
  from networkx.utils import edges_equal
  from .test_graph import BaseAttrGraphTester
  from .test_graph import TestGraph
label_desc: Use image node_id 4 for calling the TestEdgeSubgraph obj's underlying member method code with example usage: obj.test_add_node() without return types