def test_add_weight(self):
G = Graph({0: [1, 2], 1: [2]})
self.assertEqual(G.edge_weight(1, 2), 1)
G.add_edge_weight(1, 2, 1)
self.assertEqual(G.edge_weight(1, 2), 2)
self.assertEqual(G.vertex_weight(1), 1)
G.add_vertex_weight(1, 1)
self.assertEqual(G.vertex_weight(1), 2)
