def test_peek_back_when_items_returns_expected_front_of_queue(self):
        # Arrange
        queue = Queue()
        queue.put_nowait("A")
        queue.put_nowait("B")
        queue.put_nowait("C")

        # Act, Assert
        assert queue.peek_back() == "C"
    def test_peek_when_no_items_returns_none(self):
        # Arrange
        queue = Queue()

        # Act, Assert
        assert queue.peek_back() is None