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"""Tests of grpc.beta.utilities."""

import threading
import time
import unittest

from grpc.beta import implementations
from grpc.beta import utilities
from grpc.framework.foundation import future
from tests.unit.framework.common import test_constants


class _Callback(object):

    def __init__(self):
        self._condition = threading.Condition()
        self._value = None

    def accept_value(self, value):
        with self._condition:
            self._value = value
            self._condition.notify_all()

    def block_until_called(self):
        with self._condition:
            while self._value is None:
                self._condition.wait()
            return self._value


class ChannelConnectivityTest(unittest.TestCase):

    def test_lonely_channel_connectivity(self):
        channel = implementations.insecure_channel('localhost', 12345)
        callback = _Callback()

        ready_future = utilities.channel_ready_future(channel)
        ready_future.add_done_callback(callback.accept_value)
        with self.assertRaises(future.TimeoutError):
            ready_future.result(timeout=test_constants.SHORT_TIMEOUT)
        self.assertFalse(ready_future.cancelled())
        self.assertFalse(ready_future.done())
        self.assertTrue(ready_future.running())
        ready_future.cancel()
        value_passed_to_callback = callback.block_until_called()
        self.assertIs(ready_future, value_passed_to_callback)
        self.assertTrue(ready_future.cancelled())
        self.assertTrue(ready_future.done())
        self.assertFalse(ready_future.running())

    def test_immediately_connectable_channel_connectivity(self):
        server = implementations.server({})
        port = server.add_insecure_port('[::]:0')
        server.start()
        channel = implementations.insecure_channel('localhost', port)
        callback = _Callback()

        try:
            ready_future = utilities.channel_ready_future(channel)
            ready_future.add_done_callback(callback.accept_value)
            self.assertIsNone(
                ready_future.result(timeout=test_constants.LONG_TIMEOUT))
            value_passed_to_callback = callback.block_until_called()
            self.assertIs(ready_future, value_passed_to_callback)
            self.assertFalse(ready_future.cancelled())
            self.assertTrue(ready_future.done())
            self.assertFalse(ready_future.running())
            # Cancellation after maturity has no effect.
            ready_future.cancel()
            self.assertFalse(ready_future.cancelled())
            self.assertTrue(ready_future.done())
            self.assertFalse(ready_future.running())
        finally:
            ready_future.cancel()
            server.stop(0)


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