def test_delete__empty_list__ok(self):
alist = LinkedList()
assert alist.is_empty() is True
assert alist.get_head() is None
alist.delete(10)
assert alist.is_empty() is True
assert alist.get_head() is None
def test_delete_at_head__non_empty_list_with_one_element__ok(self):
alist = LinkedList(Node(1))
assert str(alist) == "1 -> None"
assert alist.get_head().data == 1
alist.delete_at_head()
assert alist.is_empty() is True
assert alist.get_head() is None
def test_insert_at_tail__empty_list__ok(self):
alist = LinkedList()
assert alist.is_empty() is True
assert alist.get_head() is None
data = 1
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert alist.get_head().data == data
assert str(alist) == f"{data} -> None"
def test_insert_at_head__non_empty_list__ok(self):
alist = LinkedList(Node("1"))
assert alist.is_empty() is False
assert alist.get_head() is not None
data = 2
alist.insert_at_head(data)
assert alist.is_empty() is False
assert alist.get_head().data == data
assert str(alist) == f"{data} -> 1 -> None"
def test_delete_at_head__empty_list_with_many_elements__ok(self):
alist = LinkedList()
for i in range(1, 4):
alist.insert_at_head(i)
assert str(alist) == "3 -> 2 -> 1 -> None"
assert alist.get_head().data == 3
alist.delete_at_head()
assert str(alist) == "2 -> 1 -> None"
assert alist.get_head().data == 2
def test_insert_at_position__empty_list_position_one__ok(self):
alist = LinkedList()
data, position = 1, 0
alist.insert_at_position(data, position)
assert alist.is_empty() is False
assert alist.get_head().data == data
assert str(alist) == f"{data} -> None"
def test_insert_at_position__position_equals_head__ok(self):
alist = LinkedList()
for i in range(1, 4):
alist.insert_at_head(i)
assert str(alist) == "3 -> 2 -> 1 -> None"
data, position = "xxx", 0
alist.insert_at_position(data, position)
assert alist.get_head().data == data
assert str(alist) == f"xxx -> 3 -> 2 -> 1 -> None"
def test_insert_at_tail__non_empty_list__ok(self):
alist = LinkedList(Node("1"))
assert alist.is_empty() is False
assert alist.get_head() is not None
data = 2
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert str(alist) == f"1 -> {data} -> None"
data = 3
alist.insert_at_tail(data)
assert alist.is_empty() is False
assert str(alist) == f"1 -> 2 -> {data} -> None"
def test_delete__non_empty_list_single_value_exists__ok(self):
alist = LinkedList(Node(1))
assert str(alist) == "1 -> None"
alist.delete(1)
assert alist.is_empty() is True
assert alist.get_head() is None
def test_get_head__ok(self):
node = Node("a")
alist = LinkedList(node)
assert alist.get_head() == node