def test_front_of_non_empty_queue_returns_first_in_value(self):
queue = Queue()
queue.enqueue(0)
queue.enqueue(1)
queue.enqueue(2)
assert queue.front() == 0
queue.dequeue()
assert queue.front() == 1
def test_dequeue(self): """ Test for dequeue method """ queue = Queue() self.assertEqual(queue.dequeue(), None) queue.enqueue(1) queue.enqueue(2) queue.enqueue(3) self.assertEqual(queue.dequeue(), 1) self.assertEqual(queue.size(), 2)
def test_has_more(self):
capacity = 10
q = Queue(capacity=capacity)
self.assertEqual(False, q.has_more())
for i in range(capacity):
q.enqueue(i)
self.assertEqual(True, q.has_more())
for i in range(capacity):
self.assertEqual(True, q.has_more())
q.dequeue()
self.assertEqual(False, q.has_more())
def test_queue_size_is_reduced_by_dequeue(self):
queue = Queue()
queue.enqueue(0)
queue.enqueue(1)
queue.enqueue(2)
assert len(queue) == 3
queue.dequeue()
assert len(queue) == 2
queue.dequeue()
queue.dequeue()
assert len(queue) == 0
def test_queue_dequeue(self):
capacity = 10
q = Queue(capacity=capacity)
for i in range(capacity):
q.enqueue(i)
for i in range(capacity):
self.assertEqual(i, q.dequeue())
def play_hot_potato_game(items, reps):
queue = Queue()
# O(n)
for item in items:
queue.enqueue(item)
# O(n - 1)
while queue.size() > 1:
# O(#reps)
for i in range(reps):
first = queue.dequeue()
print(first)
queue.enqueue(first)
print('-' * 10)
print('Removing {}'.format(queue.dequeue()))
return queue.dequeue()
def test_dequeue(self):
print('Test: test_dequeue')
queue = Queue()
print('Test: Dequeue an empty queue')
self.assertEqual(queue.dequeue(), None)
print('Test: Dequeue a queue with one element')
queue.enqueue(1)
self.assertEqual(queue.dequeue(), 1)
self.assertEqual(queue._front, None)
self.assertEqual(queue._rear, None)
print('Test: General case')
queue.enqueue(1)
queue.enqueue(2)
queue.enqueue(3)
self.assertEqual(queue.dequeue(), 1)
self.assertEqual(queue.dequeue(), 2)
self.assertEqual(queue.dequeue(), 3)
print('Success: test_dequeue')
class QueueTests(unittest.TestCase):
def setUp(self):
self.q = Queue()
def test_len_returns_0_for_empty_queue(self):
self.assertEqual(len(self.q), 0)
def test_len_returns_correct_length_after_enqueue(self):
self.assertEqual(len(self.q), 0)
self.q.enqueue(2)
self.assertEqual(len(self.q), 1)
self.q.enqueue(4)
self.assertEqual(len(self.q), 2)
self.q.enqueue(6)
self.q.enqueue(8)
self.q.enqueue(10)
self.q.enqueue(12)
self.q.enqueue(14)
self.q.enqueue(16)
self.q.enqueue(18)
self.assertEqual(len(self.q), 9)
def test_empty_dequeue(self):
self.assertIsNone(self.q.dequeue())
self.assertEqual(len(self.q), 0)
def test_dequeue_respects_order(self):
self.q.enqueue(100)
self.q.enqueue(101)
self.q.enqueue(105)
self.assertEqual(self.q.dequeue(), 100)
self.assertEqual(len(self.q), 2)
self.assertEqual(self.q.dequeue(), 101)
self.assertEqual(len(self.q), 1)
self.assertEqual(self.q.dequeue(), 105)
self.assertEqual(len(self.q), 0)
self.assertIsNone(self.q.dequeue())
self.assertEqual(len(self.q), 0)
def bfs(graph, start):
start.set_distance(0)
start.set_predecessor(None)
vertex_queue = Queue()
vertex_queue.enqueue(start)
while vertex_queue.size() > 0:
current_vertex = vertex_queue.dequeue()
for nbr in current_vertex.get_connections():
if nbr.get_color() == 'white':
nbr.set_color('gray')
nbr.set_distance(current_vertex.get_distance() + 1)
nbr.set_predecessor(current_vertex)
vertex_queue.enqueue(nbr)
current_vertex.set_color('black')
def test_dequeue_empty_queue_raises_empty_queue_exception(self):
queue = Queue()
with raises(Queue.EmptyQueueException):
queue.dequeue()
queue = Queue()
queue.enqueue(0)
queue.dequeue()
with raises(Queue.EmptyQueueException):
queue.dequeue()
def _level_order_print(self, start):
if start is None:
return
queue = Queue()
queue.enqueue(start)
traversal = ""
while len(queue) > 0:
traversal += str(queue.peek().value) + "-"
node = queue.dequeue()
if node.left:
queue.enqueue(node.left)
if node.right:
queue.enqueue(node.right)
return traversal
def _reverse_level_order_print(self, start):
if start is None:
return
queue = Queue()
stack = Stack()
queue.enqueue(start)
traversal = ""
while len(queue) > 0:
node = queue.dequeue()
stack.push(node)
if node.right:
queue.enqueue(node.right)
if node.left:
queue.enqueue(node.left)
while len(stack) > 0:
node = stack.pop()
traversal += str(node.value) + "-"
return traversal
def test_exception(self):
q = Queue(capacity=1)
q.enqueue(1)
self.assertRaises(Exception, q.enqueue, (1, ))
q.dequeue()
self.assertRaises(Exception, q.dequeue)