def test_p1_v1(a):
s = Stack()
for x in a:
s.push(x)
while s.len() > 0:
s.pop()
assert s.pop() == None
assert s.len() == 0
def test_p9_len_is_side_effect_free(values):
stack = Stack()
for v in values:
stack.push(v)
stack.len()
for v in reversed(values):
assert stack.pop() == v
assert stack.pop() == None
def test_p1_v2(a):
s = Stack()
for x in a:
s.push(x)
for x in a:
s.pop()
assert s.pop() == None
assert s.len() == 0
def test_p10_push_does_not_return_value(values):
stack = Stack()
for v in values:
assert stack.push(v) == None
def test_p4_pushing_None_raises_ValueError(v):
stack = Stack()
if v == None:
with pytest.raises(ValueError):
s.push(v)
def test_p1_lifo(values):
stack = Stack()
for v in values:
stack.push(v)
for v in reversed(values):
assert stack.pop() == v
def populate_stack(values):
stack=Stack()
for v in values:
stack.push(v)
return stack
def test_p4_pushing_None_raises_ValueError():
s = Stack()
with pytest.raises(ValueError):
s.push(None)