import unittest

from StringIO import StringIO

from util.registry.queueprocess import QueueResult
from util.registry.queuefile import QueueFile

class FakeQueue(object):
  def __init__(self):
    self.items = []

  def get(self, block):
    return self.items.pop(0)

  def put(self, data):
    self.items.append(data)


class TestQueueFile(unittest.TestCase):
  def test_basic(self):
    queue = FakeQueue()
    queue.put(QueueResult('hello world', None))
    queue.put(QueueResult('! how goes there?', None))
    queue.put(QueueResult(None, None))

    queuefile = QueueFile(queue)
    self.assertEquals(queuefile.read(), 'hello world! how goes there?')

  def test_chunk_reading(self):
    queue = FakeQueue()
    queue.put(QueueResult('hello world', None))
    queue.put(QueueResult('! how goes there?', None))
    queue.put(QueueResult(None, None))

    queuefile = QueueFile(queue)
    data = ''

    while True:
      result = queuefile.read(size=2)
      if not result:
        break

      data += result

    self.assertEquals(data, 'hello world! how goes there?')

  def test_unhandled_exception(self):
    queue = FakeQueue()
    queue.put(QueueResult('hello world', None))
    queue.put(QueueResult(None, IOError('some exception')))
    queue.put(QueueResult('! how goes there?', None))
    queue.put(QueueResult(None, None))

    queuefile = QueueFile(queue)

    with self.assertRaises(IOError):
      queuefile.read(size=12)

  def test_handled_exception(self):
    queue = FakeQueue()
    queue.put(QueueResult('hello world', None))
    queue.put(QueueResult(None, IOError('some exception')))
    queue.put(QueueResult('! how goes there?', None))
    queue.put(QueueResult(None, None))

    ex_found = [None]

    def handler(ex):
      ex_found[0] = ex

    queuefile = QueueFile(queue)
    queuefile.add_exception_handler(handler)
    queuefile.read(size=12)

    self.assertIsNotNone(ex_found[0])


if __name__ == '__main__':
  unittest.main()