def test_breadth_first_none():
g = Graph()
apple = g.add_vertex('apple')
banana = g.add_vertex('banana')
orange = g.add_vertex('orange')
kiwi = g.add_vertex('kiwi')
potato = g.add_vertex('potato')
assert g.depth_first(banana) == ['banana']
def test_breadth_first_one():
g = Graph()
apple = g.add_vertex('apple')
banana = g.add_vertex('banana')
orange = g.add_vertex('orange')
kiwi = g.add_vertex('kiwi')
potato = g.add_vertex('potato')
g.add_edge(apple, banana, 4)
g.add_edge(apple, orange, 5)
g.add_edge(orange, kiwi, 8)
g.add_edge(banana, kiwi, 7)
g.add_edge(kiwi, potato, 9)
g.add_edge(banana, potato, 11)
assert g.depth_first(banana) == [
'banana', 'potato', 'kiwi', 'orange', 'apple'
]