def test_ll_includes_false():
"""uses insert() to test includes()"""
ll = Linked_list()
ll.insert("apple")
ll.insert("banana")
ll.insert("carrot")
actual = ll.includes("donut")
expected = False
assert actual == expected
def test_merge_list_list1_none():
list1 = Linked_list()
list2 = Linked_list()
list2.insert("carrot")
list2.insert("banana")
list2.insert("apple")
actual = str(merge_lists(list1, list2))
expected = "{ apple } -> { banana } -> { carrot } -> NULL"
assert actual == expected
def test_LinkedList_kth_from_end_2():
"""uses insert to test kth_from_end() returns k places away from tail"""
ll = Linked_list()
ll.insert(2)
ll.insert(8)
ll.insert(3)
ll.insert(1)
actual = ll.kth_from_end(2)
expected = 3
assert actual == expected
def test_ll_insert():
"""tests insert() adds node to head"""
ll = Linked_list()
ll.insert("apple")
ll.insert("banana")
assert ll.head.value == "banana"
assert ll.head.next.value == 'apple'
def ll_list():
"""Sets up a linked list instance along with adds 3 nodes for testing "{ carrot } -> { banana } -> { apple } -> NULL""""
ll = Linked_list()
ll.insert("apple")
ll.insert("banana")
ll.insert("carrot")
return ll
def test_LinkedList_str():
"""uses insert() to test str()"""
ll = Linked_list()
ll.insert("apple")
ll.insert("banana")
actual = str(ll)
expected = "{ banana } -> { apple } -> NULL"
assert actual == expected
def merge_lists( list1, list2):
"""takes two linked lists and merges them starting with head1 then head2"""
# when one list is shorter
if list1.head == None:
return list2
if list2.head == None:
return list1
list1_current = list1.head
list2_current = list2.head
merged = Linked_list()
#checks is there are indexes available to merge
while list1_current != None and list2_current != None:
if list1_current != None:
if merged.head == None:
merged.insert(list1_current.value)
else:
merged.append(list1_current.value)
if list2_current != None:
if merged.head == None:
merged.insert(list2_current.value)
else:
merged.append(list2_current.value)
if list1_current and list1_current.next:
list1_current = list1_current.next
else:
list1_current = False
if list2_current and list2_current.next:
list2_current = list2_current.next
else:
list2_current = False
return merged
def test_ll_instance():
assert Linked_list()
def test_ll_head():
"""uses an empty linked list to test _init_()"""
ll = Linked_list()
assert ll.head == None
def test_ll_repr():
"""uses an empty linked list to test repr()"""
ll = Linked_list()
actual = repr(ll)
expect = "linked list : None"
assert actual == expect