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import unittest

import grpc
from grpc.framework.foundation import logging_pool

from tests.unit.framework.common import test_constants

_REQUEST = b''
_RESPONSE = b''

_UNARY_UNARY = b'/test/UnaryUnary'
_UNARY_STREAM = b'/test/UnaryStream'
_STREAM_UNARY = b'/test/StreamUnary'
_STREAM_STREAM = b'/test/StreamStream'


def handle_unary_unary(request, servicer_context):
  return _RESPONSE


def handle_unary_stream(request, servicer_context):
  for _ in range(test_constants.STREAM_LENGTH):
    yield _RESPONSE


def handle_stream_unary(request_iterator, servicer_context):
  for request in request_iterator:
    pass
  return _RESPONSE


def handle_stream_stream(request_iterator, servicer_context):
  for request in request_iterator:
    yield _RESPONSE


class _MethodHandler(grpc.RpcMethodHandler):

  def __init__(self, request_streaming, response_streaming):
    self.request_streaming = request_streaming
    self.response_streaming = response_streaming
    self.request_deserializer = None
    self.response_serializer = None
    self.unary_unary = None
    self.unary_stream = None
    self.stream_unary = None
    self.stream_stream = None
    if self.request_streaming and self.response_streaming:
      self.stream_stream = handle_stream_stream
    elif self.request_streaming:
      self.stream_unary = handle_stream_unary
    elif self.response_streaming:
      self.unary_stream = handle_unary_stream
    else:
      self.unary_unary = handle_unary_unary


class _GenericHandler(grpc.GenericRpcHandler):

  def service(self, handler_call_details):
    if handler_call_details.method == _UNARY_UNARY:
      return _MethodHandler(False, False)
    elif handler_call_details.method == _UNARY_STREAM:
      return _MethodHandler(False, True)
    elif handler_call_details.method == _STREAM_UNARY:
      return _MethodHandler(True, False)
    elif handler_call_details.method == _STREAM_STREAM:
      return _MethodHandler(True, True)
    else:
      return None


class EmptyMessageTest(unittest.TestCase):

  def setUp(self):
    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
    self._server = grpc.server((_GenericHandler(),), self._server_pool)
    port = self._server.add_insecure_port('[::]:0')
    self._server.start()
    self._channel = grpc.insecure_channel('localhost:%d' % port)

  def tearDown(self):
    self._server.stop(0)

  def testUnaryUnary(self):
    response = self._channel.unary_unary(_UNARY_UNARY)(_REQUEST)
    self.assertEqual(_RESPONSE, response)

  def testUnaryStream(self):
    response_iterator = self._channel.unary_stream(_UNARY_STREAM)(_REQUEST)
    self.assertSequenceEqual(
        [_RESPONSE] * test_constants.STREAM_LENGTH, list(response_iterator))

  def testStreamUnary(self):
    response = self._channel.stream_unary(_STREAM_UNARY)(
        [_REQUEST] * test_constants.STREAM_LENGTH)
    self.assertEqual(_RESPONSE, response)

  def testStreamStream(self):
    response_iterator = self._channel.stream_stream(_STREAM_STREAM)(
        [_REQUEST] * test_constants.STREAM_LENGTH)
    self.assertSequenceEqual(
        [_RESPONSE] * test_constants.STREAM_LENGTH, list(response_iterator))


if __name__ == '__main__':
  unittest.main(verbosity=2)

