def test_invalid_edge(self):
dag = Dag(1, 2)
with self.assertRaises(KeyError):
dag.add_edge(1, 3)
with self.assertRaises(KeyError):
dag.add_edge(5, 2)
dag.add_edge(1, 2)
def test_edge(self):
dag = Dag(1, 2)
edge = dag.add_edge(1, 2)
self.assertIs(edge, dag.edge(1, 2))
def test_two_edges(self):
dag = Dag(1, 2, 3)
edge0 = dag.add_edge(1, 2)
edge1 = dag.add_edge(2, 3)
self.assertEqual({edge0, edge1}, dag.edges())
def test_add_same_edges(self):
dag = Dag(1, 2)
edge = dag.add_edge(1, 2)
self.assertIs(edge, dag.add_edge(1, 2))
def test_add_edge(self):
dag = Dag(9, 2)
edge = dag.add_edge(9, 2)
self.assertIs(dag[9], edge.src)
self.assertIs(dag[2], edge.dst)
self.assertEqual({edge}, dag.edges())