class TestStack(unittest.TestCase):
def test_flow(self):
self.test_stack = Stack()
self.test_stack.add_item(10)
self.test_stack.add_item(20)
self.test_stack.add_item(22, 33)
assert self.test_stack.pop_item() == 33
assert self.test_stack.pop_item() == 22
assert self.test_stack.count_items() == 2
while self.test_stack.pop_item():
pass
assert self.test_stack.count_items() == 0
