def test_of_three_components(self):
     """
     1-2 3 4
     """
     nodes = self.nodes
     nodes[0].neighbors.append(nodes[1])
     nodes[1].neighbors.append(nodes[0])
     self.assertEqual(cc.connected_components(nodes), [[1, 2], [3], [4]])
 def test_of_four_components(self):
     """
     1 2 3 4
     """
     nodes = self.nodes
     self.assertEqual(
         cc.connected_components(nodes),
         [[1], [2], [3], [4]])