def test_peek_when_empty():
# TODO it should raise an exception when peeking an empty queue
q = Queue()
with pytest.raises(InvalidOperationError) as e:
q.peek()
assert str(e.value) == "Method not allowed on empty collection"
def test_peek_post_dequeue():
# TODO it should return a new first value if peek is called after a dequeue
q = Queue()
q.enqueue('apples')
q.enqueue('oranges')
actual = q.peek()
expected = 'apples'
assert actual == expected
q.dequeue()
actual = q.peek()
expected = 'oranges'
assert actual == expected
def test_enqueue_two():
q = Queue()
q.enqueue("apples")
q.enqueue("bananas")
actual = q.peek()
expected = "apples"
assert actual == expected
def test_can_peek_queue():
queue = Queue()
queue.enqueue(1)
queue.enqueue(2)
actual = queue.peek()
expected = 1
assert actual == expected
def test_queue_peek():
value = 1
node = Node(value)
queue = Queue(node)
actual = queue.peek()
expected = value
assert actual == expected
def test_peek():
q = Queue()
q.enqueue("apple")
q.enqueue("banana")
q.enqueue("cucumber")
actual = q.peek()
expected = "apple"
assert actual == expected
def test_raise_exception_empty_queue():
queue = Queue()
with pytest.raises(InvalidOperationError) as e:
queue.peek()
assert str(e.value) == "Peeking from an empty queue!"
def test_queue_peek_empty_exception():
queue = Queue()
with pytest.raises(Exception):
queue.peek()