back2back_test.py

#!/usr/bin/env python

"""
This module tests two buses attached to each other.
"""

import random
import unittest
from multiprocessing.dummy import Pool as ThreadPool
from time import sleep, time

import pytest

import can
from can import CanInterfaceNotImplementedError
from can.interfaces.udp_multicast import UdpMulticastBus

from .config import (
    IS_CI,
    IS_OSX,
    IS_PYPY,
    IS_TRAVIS,
    IS_UNIX,
    TEST_CAN_FD,
    TEST_INTERFACE_SOCKETCAN,
)


class Back2BackTestCase(unittest.TestCase):
    """Use two interfaces connected to the same CAN bus and test them against each other.

    This very class declaration runs the test on the *virtual* interface but subclasses can be created for
    other buses.
    """

    BITRATE = 500000
    TIMEOUT = 0.1

    INTERFACE_1 = "virtual"
    CHANNEL_1 = "virtual_channel_0"
    INTERFACE_2 = "virtual"
    CHANNEL_2 = "virtual_channel_0"

    def setUp(self):
        self.bus1 = can.Bus(
            channel=self.CHANNEL_1,
            interface=self.INTERFACE_1,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
        )
        self.bus2 = can.Bus(
            channel=self.CHANNEL_2,
            interface=self.INTERFACE_2,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
        )

    def tearDown(self):
        self.bus1.shutdown()
        self.bus2.shutdown()

    def _check_received_message(
        self, recv_msg: can.Message, sent_msg: can.Message
    ) -> None:
        self.assertIsNotNone(
            recv_msg, "No message was received on %s" % self.INTERFACE_2
        )
        self.assertEqual(recv_msg.arbitration_id, sent_msg.arbitration_id)
        self.assertEqual(recv_msg.is_extended_id, sent_msg.is_extended_id)
        self.assertEqual(recv_msg.is_remote_frame, sent_msg.is_remote_frame)
        self.assertEqual(recv_msg.is_error_frame, sent_msg.is_error_frame)
        self.assertEqual(recv_msg.is_fd, sent_msg.is_fd)
        self.assertEqual(recv_msg.bitrate_switch, sent_msg.bitrate_switch)
        self.assertEqual(recv_msg.dlc, sent_msg.dlc)
        if not sent_msg.is_remote_frame:
            self.assertSequenceEqual(recv_msg.data, sent_msg.data)

    def _send_and_receive(self, msg: can.Message) -> None:
        # Send with bus 1, receive with bus 2
        self.bus1.send(msg)
        recv_msg = self.bus2.recv(self.TIMEOUT)
        self._check_received_message(recv_msg, msg)
        # Some buses may receive their own messages. Remove it from the queue
        self.bus1.recv(0)

        # Send with bus 2, receive with bus 1
        # Add 1 to arbitration ID to make it a different message
        msg.arbitration_id += 1
        self.bus2.send(msg)
        # Some buses may receive their own messages. Remove it from the queue
        self.bus2.recv(0)
        recv_msg = self.bus1.recv(self.TIMEOUT)
        self._check_received_message(recv_msg, msg)

    def test_no_message(self):
        """Tests that there is no message being received if none was sent."""
        self.assertIsNone(self.bus1.recv(0.1))

    def test_multiple_shutdown(self):
        """Tests whether shutting down ``bus1`` twice does not throw any errors."""
        self.bus1.shutdown()

    @unittest.skipIf(
        IS_CI,
        "the timing sensitive behaviour cannot be reproduced reliably on a CI server",
    )
    def test_timestamp(self):
        self.bus2.send(can.Message())
        recv_msg1 = self.bus1.recv(self.TIMEOUT)
        sleep(2.0)
        self.bus2.send(can.Message())
        recv_msg2 = self.bus1.recv(self.TIMEOUT)
        delta_time = recv_msg2.timestamp - recv_msg1.timestamp
        self.assertTrue(
            1.75 <= delta_time <= 2.25,
            "Time difference should have been 2s +/- 250ms."
            "But measured {}".format(delta_time),
        )

    def test_standard_message(self):
        msg = can.Message(
            is_extended_id=False, arbitration_id=0x100, data=[1, 2, 3, 4, 5, 6, 7, 8]
        )
        self._send_and_receive(msg)

    def test_extended_message(self):
        msg = can.Message(
            is_extended_id=True,
            arbitration_id=0x123456,
            data=[10, 11, 12, 13, 14, 15, 16, 17],
        )
        self._send_and_receive(msg)

    def test_remote_message(self):
        msg = can.Message(
            is_extended_id=False, arbitration_id=0x200, is_remote_frame=True, dlc=4
        )
        self._send_and_receive(msg)

    def test_dlc_less_than_eight(self):
        msg = can.Message(is_extended_id=False, arbitration_id=0x300, data=[4, 5, 6])
        self._send_and_receive(msg)

    @unittest.skip(
        "TODO: how shall this be treated if sending messages locally? should be done uniformly"
    )
    def test_message_is_rx(self):
        """Verify that received messages have is_rx set to `False` while messages
        received on the other virtual interfaces have is_rx set to `True`.
        """
        msg = can.Message(
            is_extended_id=False, arbitration_id=0x300, data=[2, 1, 3], is_rx=False
        )
        self.bus1.send(msg)
        # Some buses may receive their own messages. Remove it from the queue
        self.bus1.recv(0)
        self_recv_msg = self.bus2.recv(self.TIMEOUT)
        self.assertIsNotNone(self_recv_msg)
        self.assertTrue(self_recv_msg.is_rx)

    @unittest.skip(
        "TODO: how shall this be treated if sending messages locally? should be done uniformly"
    )
    def test_message_is_rx_receive_own_messages(self):
        """The same as `test_message_direction` but testing with `receive_own_messages=True`."""
        bus3 = can.Bus(
            channel=self.CHANNEL_2,
            interface=self.INTERFACE_2,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
            receive_own_messages=True,
        )
        try:
            msg = can.Message(
                is_extended_id=False, arbitration_id=0x300, data=[2, 1, 3], is_rx=False
            )
            bus3.send(msg)
            self_recv_msg_bus3 = bus3.recv(self.TIMEOUT)
            self.assertTrue(self_recv_msg_bus3.is_rx)
        finally:
            bus3.shutdown()

    def test_unique_message_instances(self):
        """Verify that we have a different instances of message for each bus even with
        `receive_own_messages=True`.
        """
        bus3 = can.Bus(
            channel=self.CHANNEL_2,
            interface=self.INTERFACE_2,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
            receive_own_messages=True,
        )
        try:
            msg = can.Message(
                is_extended_id=False, arbitration_id=0x300, data=[2, 1, 3]
            )
            bus3.send(msg)
            recv_msg_bus1 = self.bus1.recv(self.TIMEOUT)
            recv_msg_bus2 = self.bus2.recv(self.TIMEOUT)
            self_recv_msg_bus3 = bus3.recv(self.TIMEOUT)

            self._check_received_message(recv_msg_bus1, recv_msg_bus2)
            self._check_received_message(recv_msg_bus2, self_recv_msg_bus3)

            recv_msg_bus1.data[0] = 4
            self.assertNotEqual(recv_msg_bus1.data, recv_msg_bus2.data)
            self.assertEqual(recv_msg_bus2.data, self_recv_msg_bus3.data)
        finally:
            bus3.shutdown()

    def test_fd_message(self):
        msg = can.Message(
            is_fd=True, is_extended_id=True, arbitration_id=0x56789, data=[0xFF] * 64
        )
        self._send_and_receive(msg)

    def test_fd_message_with_brs(self):
        msg = can.Message(
            is_fd=True,
            bitrate_switch=True,
            is_extended_id=True,
            arbitration_id=0x98765,
            data=[0xFF] * 48,
        )
        self._send_and_receive(msg)

    def test_fileno(self):
        """Test is the values returned by fileno() are valid."""
        try:
            fileno = self.bus1.fileno()
        except NotImplementedError:
            pass  # allow it to be left non-implemented
        else:
            self.assertIsNotNone(fileno)
            self.assertTrue(fileno == -1 or fileno > 0)

    def test_timestamp_is_absolute(self):
        """Tests that the timestamp that is returned is an absolute one."""
        self.bus2.send(can.Message())
        # Some buses may receive their own messages. Remove it from the queue
        self.bus2.recv(0)
        message = self.bus1.recv(self.TIMEOUT)
        # The allowed delta is still quite large to make this work on the CI server
        self.assertAlmostEqual(message.timestamp, time(), delta=self.TIMEOUT)

    def test_sub_second_timestamp_resolution(self):
        """Tests that the timestamp that is returned has sufficient resolution.

        The property that the timestamp has resolution below seconds is
        checked on two messages to reduce the probability of both having
        a timestamp of exactly a full second by accident to a negligible
        level.

        This is a regression test that was added for #1021.
        """
        self.bus2.send(can.Message())
        sleep(0.01)
        self.bus2.send(can.Message())

        recv_msg_1 = self.bus1.recv(self.TIMEOUT)
        recv_msg_2 = self.bus1.recv(self.TIMEOUT)

        sub_second_fraction_1 = recv_msg_1.timestamp % 1
        sub_second_fraction_2 = recv_msg_2.timestamp % 1
        self.assertGreater(sub_second_fraction_1 + sub_second_fraction_2, 0)

        # Some buses may receive their own messages. Remove it from the queue
        self.bus2.recv(0)
        self.bus2.recv(0)


@unittest.skipUnless(TEST_INTERFACE_SOCKETCAN, "skip testing of socketcan")
class BasicTestSocketCan(Back2BackTestCase):
    INTERFACE_1 = "socketcan"
    CHANNEL_1 = "vcan0"
    INTERFACE_2 = "socketcan"
    CHANNEL_2 = "vcan0"


# this doesn't even work on Travis CI for macOS; for example, see
# https://travis-ci.org/github/hardbyte/python-can/jobs/745389871
@unittest.skipUnless(
    IS_UNIX and not (IS_CI and IS_OSX),
    "only supported on Unix systems (but not on macOS at Travis CI and GitHub Actions)",
)
class BasicTestUdpMulticastBusIPv4(Back2BackTestCase):
    INTERFACE_1 = "udp_multicast"
    CHANNEL_1 = UdpMulticastBus.DEFAULT_GROUP_IPv4
    INTERFACE_2 = "udp_multicast"
    CHANNEL_2 = UdpMulticastBus.DEFAULT_GROUP_IPv4

    def test_unique_message_instances(self):
        with self.assertRaises(CanInterfaceNotImplementedError):
            super().test_unique_message_instances()


# this doesn't even work for loopback multicast addresses on Travis CI; for example, see
# https://travis-ci.org/github/hardbyte/python-can/builds/745065503
@unittest.skipUnless(
    IS_UNIX and not (IS_TRAVIS or (IS_CI and IS_OSX)),
    "only supported on Unix systems (but not on Travis CI; and not on macOS at GitHub Actions)",
)
class BasicTestUdpMulticastBusIPv6(Back2BackTestCase):
    HOST_LOCAL_MCAST_GROUP_IPv6 = "ff11:7079:7468:6f6e:6465:6d6f:6d63:6173"

    INTERFACE_1 = "udp_multicast"
    CHANNEL_1 = HOST_LOCAL_MCAST_GROUP_IPv6
    INTERFACE_2 = "udp_multicast"
    CHANNEL_2 = HOST_LOCAL_MCAST_GROUP_IPv6

    def test_unique_message_instances(self):
        with self.assertRaises(CanInterfaceNotImplementedError):
            super().test_unique_message_instances()


TEST_INTERFACE_ETAS = False
try:
    bus_class = can.interface._get_class_for_interface("etas")
    TEST_INTERFACE_ETAS = True
except CanInterfaceNotImplementedError:
    pass


@unittest.skipUnless(TEST_INTERFACE_ETAS, "skip testing of etas interface")
class BasicTestEtas(Back2BackTestCase):
    if TEST_INTERFACE_ETAS:
        configs = can.interface.detect_available_configs(interfaces="etas")

        INTERFACE_1 = "etas"
        CHANNEL_1 = configs[0]["channel"]
        INTERFACE_2 = "etas"
        CHANNEL_2 = configs[2]["channel"]

    def test_unique_message_instances(self):
        self.skipTest(
            "creating a second instance of a channel with differing self-reception settings is not supported"
        )


@unittest.skipUnless(TEST_INTERFACE_SOCKETCAN, "skip testing of socketcan")
class SocketCanBroadcastChannel(unittest.TestCase):
    def setUp(self):
        self.broadcast_bus = can.Bus(channel="", interface="socketcan")
        self.regular_bus = can.Bus(channel="vcan0", interface="socketcan")

    def tearDown(self):
        self.broadcast_bus.shutdown()
        self.regular_bus.shutdown()

    def test_broadcast_channel(self):
        self.broadcast_bus.send(can.Message(channel="vcan0"))
        recv_msg = self.regular_bus.recv(1)
        self.assertIsNotNone(recv_msg)
        self.assertEqual(recv_msg.channel, "vcan0")

        self.regular_bus.send(can.Message())
        recv_msg = self.broadcast_bus.recv(1)
        self.assertIsNotNone(recv_msg)
        self.assertEqual(recv_msg.channel, "vcan0")


class TestThreadSafeBus(Back2BackTestCase):
    def setUp(self):
        self.bus1 = can.ThreadSafeBus(
            channel=self.CHANNEL_1,
            interface=self.INTERFACE_1,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
        )
        self.bus2 = can.ThreadSafeBus(
            channel=self.CHANNEL_2,
            interface=self.INTERFACE_2,
            bitrate=self.BITRATE,
            fd=TEST_CAN_FD,
            single_handle=True,
        )

    @pytest.mark.timeout(180.0 if IS_PYPY else 5.0)
    def test_concurrent_writes(self):
        sender_pool = ThreadPool(100)
        receiver_pool = ThreadPool(100)

        message = can.Message(
            arbitration_id=0x123,
            channel=self.CHANNEL_1,
            is_extended_id=True,
            timestamp=121334.365,
            data=[254, 255, 1, 2],
        )
        workload = 1000 * [message]

        def sender(msg):
            self.bus1.send(msg)

        def receiver(_):
            return self.bus2.recv()

        sender_pool.map_async(sender, workload)
        for msg in receiver_pool.map(receiver, len(workload) * [None]):
            self.assertIsNotNone(msg)
            self.assertEqual(message.arbitration_id, msg.arbitration_id)
            self.assertTrue(message.equals(msg, timestamp_delta=None))

        sender_pool.close()
        sender_pool.join()
        receiver_pool.close()
        receiver_pool.join()

    @pytest.mark.timeout(180.0 if IS_PYPY else 5.0)
    def test_filtered_bus(self):
        sender_pool = ThreadPool(100)
        receiver_pool = ThreadPool(100)

        included_message = can.Message(
            arbitration_id=0x123,
            channel=self.CHANNEL_1,
            is_extended_id=True,
            timestamp=121334.365,
            data=[254, 255, 1, 2],
        )
        excluded_message = can.Message(
            arbitration_id=0x02,
            channel=self.CHANNEL_1,
            is_extended_id=True,
            timestamp=121334.300,
            data=[1, 2, 3],
        )
        workload = 500 * [included_message] + 500 * [excluded_message]
        random.shuffle(workload)

        self.bus2.set_filters([{"can_id": 0x123, "can_mask": 0xFF, "extended": True}])

        def sender(msg):
            self.bus1.send(msg)

        def receiver(_):
            return self.bus2.recv()

        sender_pool.map_async(sender, workload)
        received_msgs = receiver_pool.map(receiver, 500 * [None])

        for msg in received_msgs:
            self.assertIsNotNone(msg)
            self.assertEqual(msg.arbitration_id, included_message.arbitration_id)
            self.assertTrue(included_message.equals(msg, timestamp_delta=None))
        self.assertEqual(len(received_msgs), 500)

        sender_pool.close()
        sender_pool.join()
        receiver_pool.close()
        receiver_pool.join()


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