code: def test_digraph(self):
      G = nx.DiGraph(self.edges)
      x = list(edge_dfs(G, self.nodes))
      x_ = [(0, 1), (1, 0), (2, 1), (3, 1)]
      assert x == x_
  
imports: import pytest
  import networkx
  from networkx.algorithms import edge_dfs
  from networkx.algorithms.traversal.edgedfs import FORWARD, REVERSE
label_desc: Use image node_id 4 for calling the TestEdgeDFS obj's underlying member method code with example usage: obj.test_digraph() without return types