def test_interleaved(self):
queue = ContrivedQueue()
queue.enqueue('first')
self.assertEqual('first', queue.dequeue())
queue.enqueue('second')
queue.enqueue('third')
self.assertEqual('second', queue.dequeue())
self.assertEqual('third', queue.dequeue())
def test_index_errors(self):
queue = ContrivedQueue()
with self.assertRaises(IndexError):
queue.dequeue()
queue.enqueue(5)
queue.dequeue()
with self.assertRaises(IndexError):
queue.dequeue()
