def test_peek():
q = Queue(range(4))
for _ in range(4):
expected = q.peek()
assert expected == q.dequeue()
# queue is now empty
assert q.peek() is None
def test_peek_empty_queue():
queue = Queue()
with pytest.raises(IndexError) as exc:
queue.peek()
assert str(exc.value) == "peek from empty queue"
def test_push(self):
queue = Queue()
queue.push(1)
self.assertEqual(queue.peek(), 1)
queue.push(50)
self.assertEqual(queue.peek(), 1)
queue.push(30)
self.assertEqual(queue.peek(), 1)
queue.push(70)
self.assertEqual(queue.peek(), 1)
def test_queue(self):
q = Queue()
self.assertTrue(q.is_empty())
self.assertRaises(EmptyQueueException, q.peek)
self.assertRaises(EmptyQueueException, q.remove)
q.add(1)
self.assertFalse(q.is_empty())
q.add(2)
q.add(3)
self.assertEqual(1, q.peek())
self.assertEqual(1, q.remove())
self.assertEqual(2, q.peek())
q.remove()
q.remove()
self.assertTrue(q.is_empty())
self.assertRaises(EmptyQueueException, q.remove)
class TestQueue(TestCase):
def setUp(self):
super().setUp()
self.queue = Queue()
def test_enqueue_dequeue(self):
self.queue.enqueue(1)
self.queue.enqueue(2)
self.assertEqual(self.queue.dequeue(), 1)
self.assertEqual(self.queue.dequeue(), 2)
def test_peek(self):
self.queue.enqueue(1)
self.queue.enqueue(2)
self.assertEqual(self.queue.peek(), 1)
self.assertEqual(self.queue.size(), 2)
def test_size(self):
self.queue.enqueue(1)
self.queue.enqueue(2)
self.assertEqual(self.queue.size(), 2)
def test_is_empty(self):
self.assertTrue(self.queue.is_empty())
self.queue.enqueue(1)
self.assertFalse(self.queue.is_empty())
self.queue.dequeue()
self.assertTrue(self.queue.is_empty())
def test_peek():
queue = Queue()
queue.enqueue("a")
queue.enqueue("n")
assert queue.peek() == "a"
assert len(queue) == 2
def test_enqueue_two():
q = Queue()
q.enqueue("apples")
q.enqueue("bananas")
actual = q.peek()
expected = "apples"
assert actual == expected
def test_peek_post_dequeue():
q = Queue()
q.enqueue("apples")
q.enqueue("bananas")
q.dequeue()
actual = q.peek()
expected = "bananas"
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_pop(self):
queue = Queue()
queue.push(1)
queue.push(50)
queue.push(30)
queue.push(70)
self.assertEqual(queue.pop(), 1)
self.assertEqual(queue.pop(), 50)
queue.push(75)
self.assertEqual(queue.peek(), 30)
self.assertEqual(queue.pop(), 30)
self.assertEqual(queue.pop(), 70)
queue.push(876)
self.assertEqual(queue.peek(), 75)
self.assertEqual(queue.pop(), 75)
self.assertEqual(queue.pop(), 876)
def test_peek(self):
queue = Queue()
queue.add('test')
queue.add('win')
self.assertEqual(queue.peek(), 'test')
def test_peek_empty(self):
queue = Queue()
with self.assertRaises(ValueError):
queue.peek()
def test_peek_when_empty():
q = Queue()
with pytest.raises(InvalidOperationError):
q.peek()
