def test_is_empty(self):
stack = Stack()
assert stack.is_empty() is True
stack.push(1)
assert stack.is_empty() is False
stack.pop()
assert stack.is_empty() is True
def test_pop_all(self):
tests = [1, '0', Stack, lambda x: x, {}, [], None]
stack = Stack(tests)
assert len(stack) == len(tests)
stack.pop_all()
assert stack.is_empty() is True
def test_pop_items_with_initial_stack(self):
tests = [1, '0', Stack, lambda x: x, {}, [], None]
stack = Stack(tests)
assert len(stack) == len(tests)
for _ in tests:
stack.pop()
assert stack.is_empty() is True
def test_is_empty_returns_false_on_stack_with_elements():
stack = Stack()
stack.push(42)
assert not stack.is_empty()
def test_is_empty_returns_true_on_empty_stack():
stack = Stack()
assert stack.is_empty()