def test_insert_before_reference_does_not_exist(): ll = LinkedList() with pytest.raises(Exception) as context: ll.insert(1) ll.insert_before(3, 5) assert str(context.value) == 'No node containing: 5'
def test_insert_before_exists(): ll = LinkedList() ll.insert(3) ll.insert(1) ll.insert_before(2, 3) assert str(ll) == '{ 1 } -> { 2 } -> { 3 } -> NULL'
def test_insert_before_empty(): ll = LinkedList() with pytest.raises(Exception) as context: ll.insert_before(3, 5) assert str(context.value) == "Cannot `insert_before` on empty LinkedList"