def test_find():
ll = LinkedList()
ll.insert(0, 1)
ll.insert(0, 2)
ll.insert(0, 3)
assert (ll.find(2) == 1)
def test_peek():
ll = LinkedList()
ll.append(2)
ll.insert(0, 1)
ll.insert(1, 2)
assert (ll.front() == 1)
assert (ll.back() == 2)
assert (len(ll) == 3)
def test_insert():
ll = LinkedList()
ll.append(2)
ll.insert(0, 1)
ll.insert(1, 2)
assert (ll[0] == 1)
assert (ll[1] == 2)
assert (len(ll) == 3)
def test_pop():
ll = LinkedList()
ll.append(2)
ll.insert(0, 1)
ll.insert(1, 2)
assert (ll.pop() == 2)
assert (ll.pop_idx(0) == 1)
assert (ll[0] == 2)
assert (len(ll) == 1)
def test_delete():
ll = LinkedList()
ll.insert(0, 1)
ll.insert(0, 2)
ll.insert(0, 3)
ll.delete(1)
assert (len(ll) == 2)
assert (ll[0] == 3)
assert (ll[1] == 1)
def test_remove():
ll = LinkedList()
ll.insert(0, 1)
ll.insert(0, 2)
ll.insert(0, 3)
ll.remove(2)
assert (len(ll) == 2)
assert (ll[0] == 3)
assert (ll[1] == 1)