def test_pop_first(self):
s = Deque(['A', 'B', 'C'])
assert s.pop_first() == 'A'
assert s.length() == 2
assert s.pop_first() == 'B'
assert s.length() == 1
assert s.pop_first() == 'C'
assert s.length() == 0
assert s.is_empty() is True
with self.assertRaises(ValueError):
s.pop_first()
def test_peek_last(self):
s = Deque()
assert s.peek_last() is None
s.append('A')
assert s.peek_last() == 'A'
s.append('B')
assert s.peek_last() == 'B'
s.pop_last()
assert s.peek_last() == 'A'
s.pop_last()
assert s.peek_last() is None
def test_length(self):
s = Deque()
assert s.length() == 0
s.append('A')
assert s.length() == 1
s.append('B')
assert s.length() == 2
s.pop_last()
assert s.length() == 1
s.pop_last()
assert s.length() == 0
def test_prepend(self):
s = Deque()
s.prepend('A')
assert s.peek_first() == 'A'
assert s.peek_first() == 'A'
assert s.length() == 1
s.prepend('B')
assert s.peek_first() == 'B'
assert s.length() == 2
s.prepend('C')
assert s.peek_first() == 'C'
assert s.length() == 3
assert s.is_empty() is False
def palindrome_checker(input_string):
# convert the string to lowercase
input_string = input_string.lower()
dq = Deque()
match = True
for ch in input_string:
# skip empty spaces and insert to queue
if ch != " ":
dq.add_front(ch)
while dq.size() > 1 and match:
first = dq.remove_front()
last = dq.remove_rear()
if first != last:
match = False
return match
def test_init(self):
s = Deque()
assert s.peek_first() is None
assert s.peek_last() is None
assert s.length() == 0
assert s.is_empty() is True
def test_init_with_list(self):
s = Deque(['A', 'B', 'C'])
assert s.peek_last() == 'C'
assert s.peek_first() == 'A'
assert s.length() == 3
assert s.is_empty() is False