view tests/test-wireproto-serverreactor.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

from __future__ import absolute_import, print_function

import unittest

from mercurial import (
    ui as uimod,
    util,
    wireprotoframing as framing,
)
from mercurial.utils import cborutil

ffs = framing.makeframefromhumanstring

OK = b''.join(cborutil.streamencode({b'status': b'ok'}))


def makereactor(deferoutput=False):
    ui = uimod.ui()
    return framing.serverreactor(ui, deferoutput=deferoutput)


def sendframes(reactor, gen):
    """Send a generator of frame bytearray to a reactor.

    Emits a generator of results from ``onframerecv()`` calls.
    """
    for frame in gen:
        header = framing.parseheader(frame)
        payload = frame[framing.FRAME_HEADER_SIZE :]
        assert len(payload) == header.length

        yield reactor.onframerecv(
            framing.frame(
                header.requestid,
                header.streamid,
                header.streamflags,
                header.typeid,
                header.flags,
                payload,
            )
        )


def sendcommandframes(reactor, stream, rid, cmd, args, datafh=None):
    """Generate frames to run a command and send them to a reactor."""
    return sendframes(
        reactor, framing.createcommandframes(stream, rid, cmd, args, datafh)
    )


class ServerReactorTests(unittest.TestCase):
    def _sendsingleframe(self, reactor, f):
        results = list(sendframes(reactor, [f]))
        self.assertEqual(len(results), 1)

        return results[0]

    def assertaction(self, res, expected):
        self.assertIsInstance(res, tuple)
        self.assertEqual(len(res), 2)
        self.assertIsInstance(res[1], dict)
        self.assertEqual(res[0], expected)

    def assertframesequal(self, frames, framestrings):
        expected = [ffs(s) for s in framestrings]
        self.assertEqual(list(frames), expected)

    def test1framecommand(self):
        """Receiving a command in a single frame yields request to run it."""
        reactor = makereactor()
        stream = framing.stream(1)
        results = list(sendcommandframes(reactor, stream, 1, b'mycommand', {}))
        self.assertEqual(len(results), 1)
        self.assertaction(results[0], b'runcommand')
        self.assertEqual(
            results[0][1],
            {
                b'requestid': 1,
                b'command': b'mycommand',
                b'args': {},
                b'redirect': None,
                b'data': None,
            },
        )

        result = reactor.oninputeof()
        self.assertaction(result, b'noop')

    def test1argument(self):
        reactor = makereactor()
        stream = framing.stream(1)
        results = list(
            sendcommandframes(
                reactor, stream, 41, b'mycommand', {b'foo': b'bar'}
            )
        )
        self.assertEqual(len(results), 1)
        self.assertaction(results[0], b'runcommand')
        self.assertEqual(
            results[0][1],
            {
                b'requestid': 41,
                b'command': b'mycommand',
                b'args': {b'foo': b'bar'},
                b'redirect': None,
                b'data': None,
            },
        )

    def testmultiarguments(self):
        reactor = makereactor()
        stream = framing.stream(1)
        results = list(
            sendcommandframes(
                reactor,
                stream,
                1,
                b'mycommand',
                {b'foo': b'bar', b'biz': b'baz'},
            )
        )
        self.assertEqual(len(results), 1)
        self.assertaction(results[0], b'runcommand')
        self.assertEqual(
            results[0][1],
            {
                b'requestid': 1,
                b'command': b'mycommand',
                b'args': {b'foo': b'bar', b'biz': b'baz'},
                b'redirect': None,
                b'data': None,
            },
        )

    def testsimplecommanddata(self):
        reactor = makereactor()
        stream = framing.stream(1)
        results = list(
            sendcommandframes(
                reactor, stream, 1, b'mycommand', {}, util.bytesio(b'data!')
            )
        )
        self.assertEqual(len(results), 2)
        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'runcommand')
        self.assertEqual(
            results[1][1],
            {
                b'requestid': 1,
                b'command': b'mycommand',
                b'args': {},
                b'redirect': None,
                b'data': b'data!',
            },
        )

    def testmultipledataframes(self):
        frames = [
            ffs(
                b'1 1 stream-begin command-request new|have-data '
                b"cbor:{b'name': b'mycommand'}"
            ),
            ffs(b'1 1 0 command-data continuation data1'),
            ffs(b'1 1 0 command-data continuation data2'),
            ffs(b'1 1 0 command-data eos data3'),
        ]

        reactor = makereactor()
        results = list(sendframes(reactor, frames))
        self.assertEqual(len(results), 4)
        for i in range(3):
            self.assertaction(results[i], b'wantframe')
        self.assertaction(results[3], b'runcommand')
        self.assertEqual(
            results[3][1],
            {
                b'requestid': 1,
                b'command': b'mycommand',
                b'args': {},
                b'redirect': None,
                b'data': b'data1data2data3',
            },
        )

    def testargumentanddata(self):
        frames = [
            ffs(
                b'1 1 stream-begin command-request new|have-data '
                b"cbor:{b'name': b'command', b'args': {b'key': b'val',"
                b"b'foo': b'bar'}}"
            ),
            ffs(b'1 1 0 command-data continuation value1'),
            ffs(b'1 1 0 command-data eos value2'),
        ]

        reactor = makereactor()
        results = list(sendframes(reactor, frames))

        self.assertaction(results[-1], b'runcommand')
        self.assertEqual(
            results[-1][1],
            {
                b'requestid': 1,
                b'command': b'command',
                b'args': {
                    b'key': b'val',
                    b'foo': b'bar',
                },
                b'redirect': None,
                b'data': b'value1value2',
            },
        )

    def testnewandcontinuation(self):
        result = self._sendsingleframe(
            makereactor(),
            ffs(b'1 1 stream-begin command-request new|continuation '),
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'received command request frame with both new and '
                b'continuation flags set',
            },
        )

    def testneithernewnorcontinuation(self):
        result = self._sendsingleframe(
            makereactor(), ffs(b'1 1 stream-begin command-request 0 ')
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'received command request frame with neither new nor '
                b'continuation flags set',
            },
        )

    def testunexpectedcommanddata(self):
        """Command data frame when not running a command is an error."""
        result = self._sendsingleframe(
            makereactor(), ffs(b'1 1 stream-begin command-data 0 ignored')
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'expected sender protocol settings or command request '
                b'frame; got 2',
            },
        )

    def testunexpectedcommanddatareceiving(self):
        """Same as above except the command is receiving."""
        results = list(
            sendframes(
                makereactor(),
                [
                    ffs(
                        b'1 1 stream-begin command-request new|more '
                        b"cbor:{b'name': b'ignored'}"
                    ),
                    ffs(b'1 1 0 command-data eos ignored'),
                ],
            )
        )

        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'error')
        self.assertEqual(
            results[1][1],
            {
                b'message': b'received command data frame for request that is not '
                b'expecting data: 1',
            },
        )

    def testconflictingrequestidallowed(self):
        """Multiple fully serviced commands with same request ID is allowed."""
        reactor = makereactor()
        results = []
        outstream = reactor.makeoutputstream()
        results.append(
            self._sendsingleframe(
                reactor,
                ffs(
                    b'1 1 stream-begin command-request new '
                    b"cbor:{b'name': b'command'}"
                ),
            )
        )
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response1']
        )
        self.assertaction(result, b'sendframes')
        list(result[1][b'framegen'])
        results.append(
            self._sendsingleframe(
                reactor,
                ffs(
                    b'1 1 stream-begin command-request new '
                    b"cbor:{b'name': b'command'}"
                ),
            )
        )
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response2']
        )
        self.assertaction(result, b'sendframes')
        list(result[1][b'framegen'])
        results.append(
            self._sendsingleframe(
                reactor,
                ffs(
                    b'1 1 stream-begin command-request new '
                    b"cbor:{b'name': b'command'}"
                ),
            )
        )
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response3']
        )
        self.assertaction(result, b'sendframes')
        list(result[1][b'framegen'])

        for i in range(3):
            self.assertaction(results[i], b'runcommand')
            self.assertEqual(
                results[i][1],
                {
                    b'requestid': 1,
                    b'command': b'command',
                    b'args': {},
                    b'redirect': None,
                    b'data': None,
                },
            )

    def testconflictingrequestid(self):
        """Request ID for new command matching in-flight command is illegal."""
        results = list(
            sendframes(
                makereactor(),
                [
                    ffs(
                        b'1 1 stream-begin command-request new|more '
                        b"cbor:{b'name': b'command'}"
                    ),
                    ffs(
                        b'1 1 0 command-request new '
                        b"cbor:{b'name': b'command1'}"
                    ),
                ],
            )
        )

        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'error')
        self.assertEqual(
            results[1][1],
            {
                b'message': b'request with ID 1 already received',
            },
        )

    def testinterleavedcommands(self):
        cbor1 = b''.join(
            cborutil.streamencode(
                {
                    b'name': b'command1',
                    b'args': {
                        b'foo': b'bar',
                        b'key1': b'val',
                    },
                }
            )
        )
        cbor3 = b''.join(
            cborutil.streamencode(
                {
                    b'name': b'command3',
                    b'args': {
                        b'biz': b'baz',
                        b'key': b'val',
                    },
                }
            )
        )

        results = list(
            sendframes(
                makereactor(),
                [
                    ffs(
                        b'1 1 stream-begin command-request new|more %s'
                        % cbor1[0:6]
                    ),
                    ffs(b'3 1 0 command-request new|more %s' % cbor3[0:10]),
                    ffs(
                        b'1 1 0 command-request continuation|more %s'
                        % cbor1[6:9]
                    ),
                    ffs(
                        b'3 1 0 command-request continuation|more %s'
                        % cbor3[10:13]
                    ),
                    ffs(b'3 1 0 command-request continuation %s' % cbor3[13:]),
                    ffs(b'1 1 0 command-request continuation %s' % cbor1[9:]),
                ],
            )
        )

        self.assertEqual(
            [t[0] for t in results],
            [
                b'wantframe',
                b'wantframe',
                b'wantframe',
                b'wantframe',
                b'runcommand',
                b'runcommand',
            ],
        )

        self.assertEqual(
            results[4][1],
            {
                b'requestid': 3,
                b'command': b'command3',
                b'args': {b'biz': b'baz', b'key': b'val'},
                b'redirect': None,
                b'data': None,
            },
        )
        self.assertEqual(
            results[5][1],
            {
                b'requestid': 1,
                b'command': b'command1',
                b'args': {b'foo': b'bar', b'key1': b'val'},
                b'redirect': None,
                b'data': None,
            },
        )

    def testmissingcommanddataframe(self):
        # The reactor doesn't currently handle partially received commands.
        # So this test is failing to do anything with request 1.
        frames = [
            ffs(
                b'1 1 stream-begin command-request new|have-data '
                b"cbor:{b'name': b'command1'}"
            ),
            ffs(b'3 1 0 command-request new ' b"cbor:{b'name': b'command2'}"),
        ]
        results = list(sendframes(makereactor(), frames))
        self.assertEqual(len(results), 2)
        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'runcommand')

    def testmissingcommanddataframeflags(self):
        frames = [
            ffs(
                b'1 1 stream-begin command-request new|have-data '
                b"cbor:{b'name': b'command1'}"
            ),
            ffs(b'1 1 0 command-data 0 data'),
        ]
        results = list(sendframes(makereactor(), frames))
        self.assertEqual(len(results), 2)
        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'error')
        self.assertEqual(
            results[1][1],
            {
                b'message': b'command data frame without flags',
            },
        )

    def testframefornonreceivingrequest(self):
        """Receiving a frame for a command that is not receiving is illegal."""
        results = list(
            sendframes(
                makereactor(),
                [
                    ffs(
                        b'1 1 stream-begin command-request new '
                        b"cbor:{b'name': b'command1'}"
                    ),
                    ffs(
                        b'3 1 0 command-request new|have-data '
                        b"cbor:{b'name': b'command3'}"
                    ),
                    ffs(b'5 1 0 command-data eos ignored'),
                ],
            )
        )
        self.assertaction(results[2], b'error')
        self.assertEqual(
            results[2][1],
            {
                b'message': b'received frame for request that is not receiving: 5',
            },
        )

    def testsimpleresponse(self):
        """Bytes response to command sends result frames."""
        reactor = makereactor()
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'mycommand', {}))

        outstream = reactor.makeoutputstream()
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response']
        )
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b'1 2 stream-begin stream-settings eos cbor:b"identity"',
                b'1 2 encoded command-response continuation %s' % OK,
                b'1 2 encoded command-response continuation cbor:b"response"',
                b'1 2 0 command-response eos ',
            ],
        )

    def testmultiframeresponse(self):
        """Bytes response spanning multiple frames is handled."""
        first = b'x' * framing.DEFAULT_MAX_FRAME_SIZE
        second = b'y' * 100

        reactor = makereactor()
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'mycommand', {}))

        outstream = reactor.makeoutputstream()
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [first + second]
        )
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b'1 2 stream-begin stream-settings eos cbor:b"identity"',
                b'1 2 encoded command-response continuation %s' % OK,
                b'1 2 encoded command-response continuation Y\x80d',
                b'1 2 encoded command-response continuation %s' % first,
                b'1 2 encoded command-response continuation %s' % second,
                b'1 2 0 command-response eos ',
            ],
        )

    def testservererror(self):
        reactor = makereactor()
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'mycommand', {}))

        outstream = reactor.makeoutputstream()
        result = reactor.onservererror(outstream, 1, b'some message')
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b"1 2 stream-begin error-response 0 "
                b"cbor:{b'type': b'server', "
                b"b'message': [{b'msg': b'some message'}]}",
            ],
        )

    def test1commanddeferresponse(self):
        """Responses when in deferred output mode are delayed until EOF."""
        reactor = makereactor(deferoutput=True)
        instream = framing.stream(1)
        results = list(
            sendcommandframes(reactor, instream, 1, b'mycommand', {})
        )
        self.assertEqual(len(results), 1)
        self.assertaction(results[0], b'runcommand')

        outstream = reactor.makeoutputstream()
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response']
        )
        self.assertaction(result, b'noop')
        result = reactor.oninputeof()
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b'1 2 stream-begin stream-settings eos cbor:b"identity"',
                b'1 2 encoded command-response continuation %s' % OK,
                b'1 2 encoded command-response continuation cbor:b"response"',
                b'1 2 0 command-response eos ',
            ],
        )

    def testmultiplecommanddeferresponse(self):
        reactor = makereactor(deferoutput=True)
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        list(sendcommandframes(reactor, instream, 3, b'command2', {}))

        outstream = reactor.makeoutputstream()
        result = reactor.oncommandresponsereadyobjects(
            outstream, 1, [b'response1']
        )
        self.assertaction(result, b'noop')
        result = reactor.oncommandresponsereadyobjects(
            outstream, 3, [b'response2']
        )
        self.assertaction(result, b'noop')
        result = reactor.oninputeof()
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b'1 2 stream-begin stream-settings eos cbor:b"identity"',
                b'1 2 encoded command-response continuation %s' % OK,
                b'1 2 encoded command-response continuation cbor:b"response1"',
                b'1 2 0 command-response eos ',
                b'3 2 encoded command-response continuation %s' % OK,
                b'3 2 encoded command-response continuation cbor:b"response2"',
                b'3 2 0 command-response eos ',
            ],
        )

    def testrequestidtracking(self):
        reactor = makereactor(deferoutput=True)
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        list(sendcommandframes(reactor, instream, 3, b'command2', {}))
        list(sendcommandframes(reactor, instream, 5, b'command3', {}))

        # Register results for commands out of order.
        outstream = reactor.makeoutputstream()
        reactor.oncommandresponsereadyobjects(outstream, 3, [b'response3'])
        reactor.oncommandresponsereadyobjects(outstream, 1, [b'response1'])
        reactor.oncommandresponsereadyobjects(outstream, 5, [b'response5'])

        result = reactor.oninputeof()
        self.assertaction(result, b'sendframes')
        self.assertframesequal(
            result[1][b'framegen'],
            [
                b'3 2 stream-begin stream-settings eos cbor:b"identity"',
                b'3 2 encoded command-response continuation %s' % OK,
                b'3 2 encoded command-response continuation cbor:b"response3"',
                b'3 2 0 command-response eos ',
                b'1 2 encoded command-response continuation %s' % OK,
                b'1 2 encoded command-response continuation cbor:b"response1"',
                b'1 2 0 command-response eos ',
                b'5 2 encoded command-response continuation %s' % OK,
                b'5 2 encoded command-response continuation cbor:b"response5"',
                b'5 2 0 command-response eos ',
            ],
        )

    def testduplicaterequestonactivecommand(self):
        """Receiving a request ID that matches a request that isn't finished."""
        reactor = makereactor()
        stream = framing.stream(1)
        list(sendcommandframes(reactor, stream, 1, b'command1', {}))
        results = list(sendcommandframes(reactor, stream, 1, b'command1', {}))

        self.assertaction(results[0], b'error')
        self.assertEqual(
            results[0][1],
            {
                b'message': b'request with ID 1 is already active',
            },
        )

    def testduplicaterequestonactivecommandnosend(self):
        """Same as above but we've registered a response but haven't sent it."""
        reactor = makereactor()
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        outstream = reactor.makeoutputstream()
        reactor.oncommandresponsereadyobjects(outstream, 1, [b'response'])

        # We've registered the response but haven't sent it. From the
        # perspective of the reactor, the command is still active.

        results = list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        self.assertaction(results[0], b'error')
        self.assertEqual(
            results[0][1],
            {
                b'message': b'request with ID 1 is already active',
            },
        )

    def testduplicaterequestaftersend(self):
        """We can use a duplicate request ID after we've sent the response."""
        reactor = makereactor()
        instream = framing.stream(1)
        list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        outstream = reactor.makeoutputstream()
        res = reactor.oncommandresponsereadyobjects(outstream, 1, [b'response'])
        list(res[1][b'framegen'])

        results = list(sendcommandframes(reactor, instream, 1, b'command1', {}))
        self.assertaction(results[0], b'runcommand')

    def testprotocolsettingsnoflags(self):
        result = self._sendsingleframe(
            makereactor(), ffs(b'0 1 stream-begin sender-protocol-settings 0 ')
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'sender protocol settings frame must have '
                b'continuation or end of stream flag set',
            },
        )

    def testprotocolsettingsconflictflags(self):
        result = self._sendsingleframe(
            makereactor(),
            ffs(b'0 1 stream-begin sender-protocol-settings continuation|eos '),
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'sender protocol settings frame cannot have both '
                b'continuation and end of stream flags set',
            },
        )

    def testprotocolsettingsemptypayload(self):
        result = self._sendsingleframe(
            makereactor(),
            ffs(b'0 1 stream-begin sender-protocol-settings eos '),
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'sender protocol settings frame did not contain CBOR '
                b'data',
            },
        )

    def testprotocolsettingsmultipleobjects(self):
        result = self._sendsingleframe(
            makereactor(),
            ffs(
                b'0 1 stream-begin sender-protocol-settings eos '
                b'\x46foobar\x43foo'
            ),
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'sender protocol settings frame contained multiple '
                b'CBOR values',
            },
        )

    def testprotocolsettingscontentencodings(self):
        reactor = makereactor()

        result = self._sendsingleframe(
            reactor,
            ffs(
                b'0 1 stream-begin sender-protocol-settings eos '
                b'cbor:{b"contentencodings": [b"a", b"b"]}'
            ),
        )
        self.assertaction(result, b'wantframe')

        self.assertEqual(reactor._state, b'idle')
        self.assertEqual(
            reactor._sendersettings[b'contentencodings'], [b'a', b'b']
        )

    def testprotocolsettingsmultipleframes(self):
        reactor = makereactor()

        data = b''.join(
            cborutil.streamencode(
                {
                    b'contentencodings': [b'value1', b'value2'],
                }
            )
        )

        results = list(
            sendframes(
                reactor,
                [
                    ffs(
                        b'0 1 stream-begin sender-protocol-settings continuation %s'
                        % data[0:5]
                    ),
                    ffs(b'0 1 0 sender-protocol-settings eos %s' % data[5:]),
                ],
            )
        )

        self.assertEqual(len(results), 2)

        self.assertaction(results[0], b'wantframe')
        self.assertaction(results[1], b'wantframe')

        self.assertEqual(reactor._state, b'idle')
        self.assertEqual(
            reactor._sendersettings[b'contentencodings'], [b'value1', b'value2']
        )

    def testprotocolsettingsbadcbor(self):
        result = self._sendsingleframe(
            makereactor(),
            ffs(b'0 1 stream-begin sender-protocol-settings eos badvalue'),
        )
        self.assertaction(result, b'error')

    def testprotocolsettingsnoninitial(self):
        # Cannot have protocol settings frames as non-initial frames.
        reactor = makereactor()

        stream = framing.stream(1)
        results = list(sendcommandframes(reactor, stream, 1, b'mycommand', {}))
        self.assertEqual(len(results), 1)
        self.assertaction(results[0], b'runcommand')

        result = self._sendsingleframe(
            reactor, ffs(b'0 1 0 sender-protocol-settings eos ')
        )
        self.assertaction(result, b'error')
        self.assertEqual(
            result[1],
            {
                b'message': b'expected command request frame; got 8',
            },
        )


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)