text: from floweaver.layered_graph import LayeredGraph, Ordering
  
  
  def test_remove_node():
      G = LayeredGraph()
      G.add_edges_from([('a', 'b'), ('a', 'c'), ('b', 'd')])
      G.ordering = Ordering([['a'], ['b', 'c'], ['d']])
      assert sorted(G.nodes()) == ['a', 'b', 'c', 'd']
  
      G.remove_node('c')
      assert sorted(G.nodes()) == ['a', 'b', 'd']
      assert G.ordering == Ordering([['a'], ['b'], ['d']])
  