def test_prepend(self): ll = LinkedList() # Prepend should always update head node ll.prepend('C') assert ll.head.data == 'C' # New head assert ll.tail.data == 'C' # New head ll.prepend('B') assert ll.head.data == 'B' # New head assert ll.tail.data == 'C' # Unchanged ll.prepend('A') assert ll.head.data == 'A' # New head assert ll.tail.data == 'C' # Unchanged
def test_append(self): ll = LinkedList() # Append should always update tail node ll.append('A') assert ll.head.data == 'A' # New head assert ll.tail.data == 'A' # New tail ll.append('B') assert ll.head.data == 'A' # Unchanged assert ll.tail.data == 'B' # New tail ll.append('C') assert ll.head.data == 'A' # Unchanged assert ll.tail.data == 'C' # New tail
def test_length_after_delete(self): ll = LinkedList(['A', 'B', 'C', 'D', 'E']) assert ll.length() == 5 # Delete should decrease length ll.delete('A') assert ll.length() == 4 ll.delete('E') assert ll.length() == 3 ll.delete('C') assert ll.length() == 2 ll.delete('D') assert ll.length() == 1 ll.delete('B') assert ll.length() == 0
def test_length_after_append_and_prepend(self): ll = LinkedList() assert ll.length() == 0 # Append and prepend should increase length ll.append('C') assert ll.length() == 1 ll.prepend('B') assert ll.length() == 2 ll.append('D') assert ll.length() == 3 ll.prepend('A') assert ll.length() == 4
def test_length_after_prepend(self): ll = LinkedList() assert ll.length() == 0 # Prepend should increase length ll.prepend('C') assert ll.length() == 1 ll.prepend('B') assert ll.length() == 2 ll.prepend('A') assert ll.length() == 3
def test_items_after_prepend(self): ll = LinkedList() assert ll.items() == [] # Prepend should add new item to head of list ll.prepend('C') assert ll.items() == ['C'] ll.prepend('B') assert ll.items() == ['B', 'C'] ll.prepend('A') assert ll.items() == ['A', 'B', 'C']
def test_items_after_append(self): ll = LinkedList() assert ll.items() == [] # Append should add new item to tail of list ll.append('A') assert ll.items() == ['A'] ll.append('B') assert ll.items() == ['A', 'B'] ll.append('C') assert ll.items() == ['A', 'B', 'C']
def test_init_with_list(self): ll = LinkedList(['A', 'B', 'C']) # Initializer should append items in order assert ll.head.data == 'A' # First item assert ll.tail.data == 'C' # Last item
def test_init(self): ll = LinkedList() # Initializer should add instance properties assert ll.head is None # First node assert ll.tail is None # Last node
def test_delete_with_item_not_in_list(self): ll = LinkedList(['A', 'B', 'C']) # Delete should raise error if item not found with self.assertRaises(ValueError): ll.delete('X') # Item not found in list
def test_delete_with_5_items(self): ll = LinkedList(['A', 'B', 'C', 'D', 'E']) assert ll.head.data == 'A' # First item assert ll.tail.data == 'E' # Last item ll.delete('A') assert ll.head.data == 'B' # New head assert ll.tail.data == 'E' # Unchanged ll.delete('E') assert ll.head.data == 'B' # Unchanged assert ll.tail.data == 'D' # New tail ll.delete('C') assert ll.head.data == 'B' # Unchanged assert ll.tail.data == 'D' # Unchanged ll.delete('D') assert ll.head.data == 'B' # Unchanged assert ll.tail.data == 'B' # New tail ll.delete('B') assert ll.head is None # No head assert ll.tail is None # No tail
def test_delete_with_3_items(self): ll = LinkedList(['A', 'B', 'C']) assert ll.head.data == 'A' # First item assert ll.tail.data == 'C' # Last item ll.delete('A') assert ll.head.data == 'B' # New head assert ll.tail.data == 'C' # Unchanged ll.delete('C') assert ll.head.data == 'B' # Unchanged assert ll.tail.data == 'B' # New tail ll.delete('B') assert ll.head is None # No head assert ll.tail is None # No tail # Delete should raise error if item was already deleted with self.assertRaises(ValueError): ll.delete('A') # Item no longer in list with self.assertRaises(ValueError): ll.delete('B') # Item no longer in list with self.assertRaises(ValueError): ll.delete('C') # Item no longer in list
def test_find(self): ll = LinkedList(['A', 'B', 'C']) assert ll.find(lambda item: item == 'B') == 'B' # Match equality assert ll.find(lambda item: item < 'B') == 'A' # Match less than assert ll.find(lambda item: item > 'B') == 'C' # Match greater than assert ll.find(lambda item: item == 'X') is None # No matching item