def test_add_vertex(self):
d = DirectedGraph({1: [2, 3], 2: [4], 3: [4]})
d.add_vertex(5)
self.assertTrue(5 in d)
self.assertEqual(d.get_indegree(5), 0)
self.assertEqual(d.get_outdegree(5), 0)
self.assertEqual(d[5], [])
def test_add_vertex():
graph = DirectedGraph({1: [2, 3], 2: [4], 3: [4]})
graph.add_vertex(5)
assert 5 in graph
assert graph.get_indegree(5) == 0
assert graph.get_outdegree(5) == 0
assert graph.get_neighbors(5) == []