def test_display_method_returns_string_of_none_if_list_is_empty():
"""Test that the display method of the Singly Linked List class returns the
string of None of the list is empty."""
ll = SinglyLinkedList()
assert ll.display() == 'None'
def test_display_method_returns_correct_visual_representation_of_list():
"""Test that the display method of the Singly Linked List returns an
accurate visual representation of the list, complete with all Nodes."""
ll = SinglyLinkedList()
for i in range(3):
ll.add_node(i)
assert ll.display() == '[ 2 ] -> [ 1 ] -> [ 0 ] -> None'
