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