def test_insert_in_order_when_empty(self):
"""
Inserting a node in an empty sorted list just appends the new node.
"""
ll = LinkedList()
ll.insert_in_order(LinkedList(8))
self.assertEqual(None, ll.at(0).value)
self.assertEqual(8, ll.at(1).value)
def test_at(self):
"""
At(N) returns the Nth node in the list (where 0 is the sentinel.)
"""
ll = LinkedList()
second_node = LinkedList(fake_value())
third_node = LinkedList(fake_value())
fourth_node = LinkedList(fake_value())
ll.append(second_node)
ll.append(third_node)
ll.append(fourth_node)
self.assertEqual(second_node, ll.at(1))
self.assertEqual(third_node, ll.at(2))
self.assertEqual(fourth_node, ll.at(3))
def test_insert_in_order_maintains_order_of_values(self):
"""
Inserting nodes of arbitrary values results in the list maintaining the
sorted order of nodes based on their value.
Example: inserting 8, 6, 7, 5, 3, 0, 9 results in: 0, 3, 5, 6, 7, 8, 9
"""
values = [8, 6, 7, 5, 3, 0, 9]
ll = LinkedList()
for value in values:
ll.insert_in_order(LinkedList(value))
self.assertEqual(None, ll.at(0).value)
self.assertEqual(0, ll.at(1).value)
self.assertEqual(3, ll.at(2).value)
self.assertEqual(5, ll.at(3).value)
self.assertEqual(6, ll.at(4).value)
self.assertEqual(7, ll.at(5).value)
self.assertEqual(8, ll.at(6).value)
self.assertEqual(9, ll.at(7).value)
def test_insert_in_order_less_than(self):
"""
Inserting a node in a sorted list when the node's value is less than an
existing node's value places the new node before the existing one.
Example: None -> 8 becomes None -> 6 -> 8
"""
ll = LinkedList()
ll.insert_in_order(LinkedList(8))
ll.insert_in_order(LinkedList(6))
self.assertEqual(6, ll.at(1).value)
def test_insert_in_order_greater_than(self):
"""
Inserting a node in a sorted list when the node's value is greater than
an existing node's value places the new node after te existing one.
Example: None -> 8 becomes None -> 8 -> 9
"""
ll = LinkedList()
ll.insert_in_order(LinkedList(8))
ll.insert_in_order(LinkedList(9))
self.assertEqual(9, ll.at(2).value)
def test_get_element_at_invalid_negative_index(self):
list = LinkedList()
list.push(5).push(10).push(20).push(50)
self.assertIs(list.at(-10), None)
def test_get_element_at_negative_index(self):
list = LinkedList()
list.push(5).push(10).push(20).push(50)
self.assertEqual(list.at(-3).value, 10)
def test_get_element_at_last_index(self):
list = LinkedList()
list.push(5).push(10).push(20).push(50)
self.assertEqual(list.at(-1).value, 50)
