def test_order(g):
gr = Graph()
assert gr.order == 0
for i in range(MAX):
gr.insert(i)
assert gr.order == i + 1
def test_str(g):
g = Graph()
assert str(g) == 'Graph(set(), set())'
g.insert(0)
g.insert(1)
assert str(g) == 'Graph({0, 1}, set())'
g.link(0, 1, 5)
assert str(g) == 'Graph({0, 1}, {(0, 1, 5)})'
def test_add_raises(g):
g = Graph()
g.insert(0)
with pytest.raises(KeyError):
g.insert(0)
