def test_push_front(self):
q = LinkedDeque()
q.push_front("A")
assert q.length() == 1
q.push_front("B")
assert q.length() == 2
assert q.front() == "B"
assert q.back() == "A"
def test_pop_front(self):
q = LinkedDeque()
with self.assertRaises(ValueError):
q.pop_front()
q.push_front("A")
assert q.length() == 1
assert q.pop_front() == "A"
assert q.is_empty() is True
q.push_front("one")
q.push_back("two")
assert q.pop_front() == "one"
assert q.pop_front() == "two"
with self.assertRaises(ValueError):
q.pop_front()
assert q.is_empty() is True
def test_push_front(self):
dq = LinkedDeque()
dq.push_front('A')
assert dq.length() == 1
assert dq.front() == 'A'
dq.push_front('B')
assert dq.length() == 2
assert dq.front() == 'B'
dq.push_front('C')
assert dq.length() == 3
assert dq.front() == 'C'
assert dq.is_empty() == False