def test_del_edge():
graph = DirectedGraph({1: [2]})
assert graph.is_edge(1, 2)
graph.del_edge(1, 2)
assert not graph.is_edge(1, 2)
graph = DirectedGraph({1: [2, 2]})
assert graph.is_edge(1, 2)
graph.del_edge(1, 2)
assert graph.is_edge(1, 2)
graph.del_edge(1, 2)
assert not graph.is_edge(1, 2)
def test_del_edge(self):
d = DirectedGraph({1: [2]})
self.assertTrue(d.is_edge(1, 2))
d.del_edge(1, 2)
self.assertFalse(d.is_edge(1, 2))