def test_dequeue_efficiency(self):
"""
Dequeuing a value is O(n).
"""
print("This test will take a while...") # See the comment below.
time_samples = []
for _ in range(0, 1000):
pq = NaivePriorityQueue()
pq.enqueue('fake')
start_time = time.time()
pq.dequeue()
end_time = time.time()
time_samples.append(end_time - start_time)
small_average_dequeue_time = sum(time_samples) / float(
len(time_samples))
large_queue = NaivePriorityQueue()
for _ in range(0, 1000000):
large_queue.enqueue('fake')
large_time_samples = []
for _ in range(0, 1000):
start_time = time.time()
large_queue.dequeue()
end_time = time.time()
large_time_samples.append(end_time - start_time)
large_average_dequeue_time = sum(large_time_samples) / float(
len(large_time_samples))
self.assertNotAlmostEqual(small_average_dequeue_time,
large_average_dequeue_time,
delta=small_average_dequeue_time)
def test_dequeue_three(self):
"""
Dequeuing from a three-element queue returns the jobs with the highest
priority.
"""
pq = NaivePriorityQueue()
lower_priority = Job(1, 'like')
middle_priority = Job(3, 'who')
higher_priority = Job(5, 'on')
pq.enqueue(higher_priority)
pq.enqueue(lower_priority)
pq.enqueue(middle_priority)
self.assertEqual(higher_priority, pq.dequeue())
self.assertEqual(middle_priority, pq.dequeue())
self.assertEqual(lower_priority, pq.dequeue())
def test_dequeue_three_internal(self):
"""
Dequeuing from a three-element queue removes each dequeued value from
the internal list, highest-priority first.
"""
pq = NaivePriorityQueue()
lower_priority = Job(1, 'top')
middle_priority = Job(3, 'of')
higher_priority = Job(5, 'this')
pq.enqueue(higher_priority)
pq.enqueue(lower_priority)
pq.enqueue(middle_priority)
_ = pq.dequeue()
self.assertEqual(lower_priority, pq.data[0])
_ = pq.dequeue()
self.assertEqual(lower_priority, pq.data[0])
def test_dequeue_one(self):
"""
Dequeuing from a single-element queue returns the single value.
"""
pq = NaivePriorityQueue()
j = Job(5, 'the')
pq.enqueue(j)
self.assertEqual(j, pq.dequeue())
def test_empty_after_dequeue(self):
"""
A queue with one enqueued value is empty after dequeuing.
"""
pq = NaivePriorityQueue()
pq.enqueue(Job(1, 'was'))
_ = pq.dequeue()
self.assertTrue(pq.is_empty())
def test_not_empty_multiple(self):
"""
A queue with two enqueued values is not empty after dequeuing only one.
"""
pq = NaivePriorityQueue()
pq.enqueue(Job(1, 'hustling'))
pq.enqueue(Job(3, 'arguing and bustling'))
_ = pq.dequeue()
self.assertFalse(pq.is_empty())
def test_dequeue_two(self):
"""
Dequeuing from a two-element queue returns the one with highest priority.
"""
pq = NaivePriorityQueue()
lower_priority = Job(1, 'of')
higher_priority = Job(3, 'the')
pq.enqueue(higher_priority)
pq.enqueue(lower_priority)
self.assertEqual(higher_priority, pq.dequeue())
def test_dequeue_one_internal(self):
"""
Dequeuing from a single-element queue removes it from the internal list.
"""
pq = NaivePriorityQueue()
job = Job(5, 'crown')
pq.enqueue(job)
self.assertEqual(1, len(pq.data))
_ = pq.dequeue()
self.assertEqual(0, len(pq.data))
def test_dequeue_two_internal(self):
"""
Dequeuing from a two-element queue removes the job with the highest
priority from the list.
"""
pq = NaivePriorityQueue()
lower_priority = Job(1, 'metropolis')
higher_priority = Job(3, 'shining')
pq.enqueue(higher_priority)
pq.enqueue(lower_priority)
_ = pq.dequeue()
self.assertEqual(lower_priority, pq.data[0])
self.assertEqual(1, len(pq.data))
def test_initial_dequeue(self):
"""
Dequeuing from an empty queue returns None.
"""
pq = NaivePriorityQueue()
self.assertIsNone(pq.dequeue())
