def test_empty_append(self):
'''
Tests append method on an empty LinkedList.
'''
ll = LinkedList()
ll.append(0)
assert ll.head.x == 0
def test_delete_first_of_two(self):
'''
Tests delete method when two equal values occur in list.
Only first occurrence of value ought to be deleted.
'''
ll = LinkedList()
ll.prepend(0)
ll.append(1)
ll.append(2)
ll.append(0)
ll.delete(0)
assert ll.head.x == 1
assert ll.head.next.next.x == 0
def test_set_insert(self):
'''
Tests _set_insert method which changes implication of LinkedList.insert
'''
ll = LinkedList()
ll._set_insert('prepend')
ll.insert(0)
ll.insert(1)
assert ll.head.x == 1
ll._set_insert('append')
ll.insert(2)
assert ll.head.next.next.x == 2
def test_delete_unique_value(self):
'''
Tests delete method when value is unique.
'''
ll = LinkedList()
ll.prepend(0)
ll.append(1)
assert ll.head.next.x == 1
ll.delete(1)
assert ll.head.next == None
def test_insert_after(self):
'''
Tests insert_after method by creating LinkedList of length 1 and inserting after head.
'''
ll = LinkedList()
ll.prepend(0)
ll.insert_after(1, ll.head)
assert ll.head.next.x == 1
def test_get_size(self):
'''
Tests get_size method which returns number of length.
'''
ll = LinkedList()
ll.prepend(0)
ll.append(1)
ll.append(2)
assert ll.get_size() == 3
def test_get_keys(self):
'''
Tests get_keys method which returns number of keys.
'''
ll = LinkedList()
ll.prepend(0)
ll.append(1)
ll.append(2)
assert ll.get_keys() == 3