import asyncio
import contextlib
import logging
import socket
import sys
import unittest
import uuid
from unittest.mock import Mock, patch

from websockets.asyncio.compatibility import TimeoutError, aiter, anext, asyncio_timeout
from websockets.asyncio.connection import *
from websockets.asyncio.connection import broadcast
from websockets.exceptions import (
    ConcurrencyError,
    ConnectionClosedError,
    ConnectionClosedOK,
)
from websockets.frames import CloseCode, Frame, Opcode
from websockets.protocol import CLIENT, SERVER, Protocol, State

from ..protocol import RecordingProtocol
from ..utils import MS, AssertNoLogsMixin
from .connection import InterceptingConnection
from .utils import alist


# Connection implements symmetrical behavior between clients and servers.
# All tests run on the client side and the server side to validate this.


class ClientConnectionTests(AssertNoLogsMixin, unittest.IsolatedAsyncioTestCase):
    LOCAL = CLIENT
    REMOTE = SERVER

    async def asyncSetUp(self):
        loop = asyncio.get_running_loop()
        socket_, remote_socket = socket.socketpair()
        self.transport, self.connection = await loop.create_connection(
            lambda: Connection(Protocol(self.LOCAL), close_timeout=2 * MS),
            sock=socket_,
        )
        self.remote_transport, self.remote_connection = await loop.create_connection(
            lambda: InterceptingConnection(RecordingProtocol(self.REMOTE)),
            sock=remote_socket,
        )

    async def asyncTearDown(self):
        await self.remote_connection.close()
        await self.connection.close()

    # Test helpers built upon RecordingProtocol and InterceptingConnection.

    async def assertFrameSent(self, frame):
        """Check that a single frame was sent."""
        # Let the remote side process messages.
        # Two runs of the event loop are required for answering pings.
        await asyncio.sleep(0)
        await asyncio.sleep(0)
        self.assertEqual(self.remote_connection.protocol.get_frames_rcvd(), [frame])

    async def assertFramesSent(self, frames):
        """Check that several frames were sent."""
        # Let the remote side process messages.
        # Two runs of the event loop are required for answering pings.
        await asyncio.sleep(0)
        await asyncio.sleep(0)
        self.assertEqual(self.remote_connection.protocol.get_frames_rcvd(), frames)

    async def assertNoFrameSent(self):
        """Check that no frame was sent."""
        # Run the event loop twice for consistency with assertFrameSent.
        await asyncio.sleep(0)
        await asyncio.sleep(0)
        self.assertEqual(self.remote_connection.protocol.get_frames_rcvd(), [])

    @contextlib.asynccontextmanager
    async def delay_frames_rcvd(self, delay):
        """Delay frames before they're received by the connection."""
        with self.remote_connection.delay_frames_sent(delay):
            yield
            await asyncio.sleep(MS)  # let the remote side process messages

    @contextlib.asynccontextmanager
    async def delay_eof_rcvd(self, delay):
        """Delay EOF before it's received by the connection."""
        with self.remote_connection.delay_eof_sent(delay):
            yield
            await asyncio.sleep(MS)  # let the remote side process messages

    @contextlib.asynccontextmanager
    async def drop_frames_rcvd(self):
        """Drop frames before they're received by the connection."""
        with self.remote_connection.drop_frames_sent():
            yield
            await asyncio.sleep(MS)  # let the remote side process messages

    @contextlib.asynccontextmanager
    async def drop_eof_rcvd(self):
        """Drop EOF before it's received by the connection."""
        with self.remote_connection.drop_eof_sent():
            yield
            await asyncio.sleep(MS)  # let the remote side process messages

    # Test __aenter__ and __aexit__.

    async def test_aenter(self):
        """__aenter__ returns the connection itself."""
        async with self.connection as connection:
            self.assertIs(connection, self.connection)

    async def test_aexit(self):
        """__aexit__ closes the connection with code 1000."""
        async with self.connection:
            await self.assertNoFrameSent()
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe8"))

    async def test_exit_with_exception(self):
        """__exit__ with an exception closes the connection with code 1011."""
        with self.assertRaises(RuntimeError):
            async with self.connection:
                raise RuntimeError
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xf3"))

    # Test __aiter__.

    async def test_aiter_text(self):
        """__aiter__ yields text messages."""
        aiterator = aiter(self.connection)
        await self.remote_connection.send("😀")
        self.assertEqual(await anext(aiterator), "😀")
        await self.remote_connection.send("😀")
        self.assertEqual(await anext(aiterator), "😀")

    async def test_aiter_binary(self):
        """__aiter__ yields binary messages."""
        aiterator = aiter(self.connection)
        await self.remote_connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(await anext(aiterator), b"\x01\x02\xfe\xff")
        await self.remote_connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(await anext(aiterator), b"\x01\x02\xfe\xff")

    async def test_aiter_mixed(self):
        """__aiter__ yields a mix of text and binary messages."""
        aiterator = aiter(self.connection)
        await self.remote_connection.send("😀")
        self.assertEqual(await anext(aiterator), "😀")
        await self.remote_connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(await anext(aiterator), b"\x01\x02\xfe\xff")

    async def test_aiter_connection_closed_ok(self):
        """__aiter__ terminates after a normal closure."""
        aiterator = aiter(self.connection)
        await self.remote_connection.close()
        with self.assertRaises(StopAsyncIteration):
            await anext(aiterator)

    async def test_aiter_connection_closed_error(self):
        """__aiter__ raises ConnectionClosedError after an error."""
        aiterator = aiter(self.connection)
        await self.remote_connection.close(code=CloseCode.INTERNAL_ERROR)
        with self.assertRaises(ConnectionClosedError):
            await anext(aiterator)

    # Test recv.

    async def test_recv_text(self):
        """recv receives a text message."""
        await self.remote_connection.send("😀")
        self.assertEqual(await self.connection.recv(), "😀")

    async def test_recv_binary(self):
        """recv receives a binary message."""
        await self.remote_connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(await self.connection.recv(), b"\x01\x02\xfe\xff")

    async def test_recv_text_as_bytes(self):
        """recv receives a text message as bytes."""
        await self.remote_connection.send("😀")
        self.assertEqual(await self.connection.recv(decode=False), "😀".encode())

    async def test_recv_binary_as_text(self):
        """recv receives a binary message as a str."""
        await self.remote_connection.send("😀".encode())
        self.assertEqual(await self.connection.recv(decode=True), "😀")

    async def test_recv_fragmented_text(self):
        """recv receives a fragmented text message."""
        await self.remote_connection.send(["😀", "😀"])
        self.assertEqual(await self.connection.recv(), "😀😀")

    async def test_recv_fragmented_binary(self):
        """recv receives a fragmented binary message."""
        await self.remote_connection.send([b"\x01\x02", b"\xfe\xff"])
        self.assertEqual(await self.connection.recv(), b"\x01\x02\xfe\xff")

    async def test_recv_connection_closed_ok(self):
        """recv raises ConnectionClosedOK after a normal closure."""
        await self.remote_connection.close()
        with self.assertRaises(ConnectionClosedOK):
            await self.connection.recv()

    async def test_recv_connection_closed_error(self):
        """recv raises ConnectionClosedError after an error."""
        await self.remote_connection.close(code=CloseCode.INTERNAL_ERROR)
        with self.assertRaises(ConnectionClosedError):
            await self.connection.recv()

    async def test_recv_non_utf8_text(self):
        """recv receives a non-UTF-8 text message."""
        await self.remote_connection.send(b"\x01\x02\xfe\xff", text=True)
        with self.assertRaises(ConnectionClosedError):
            await self.connection.recv()
        await self.assertFrameSent(
            Frame(Opcode.CLOSE, b"\x03\xefinvalid start byte at position 2")
        )

    async def test_recv_during_recv(self):
        """recv raises ConcurrencyError when called concurrently."""
        recv_task = asyncio.create_task(self.connection.recv())
        await asyncio.sleep(0)  # let the event loop start recv_task
        self.addCleanup(recv_task.cancel)

        with self.assertRaises(ConcurrencyError) as raised:
            await self.connection.recv()
        self.assertEqual(
            str(raised.exception),
            "cannot call recv while another coroutine "
            "is already running recv or recv_streaming",
        )

    async def test_recv_during_recv_streaming(self):
        """recv raises ConcurrencyError when called concurrently with recv_streaming."""
        recv_streaming_task = asyncio.create_task(
            alist(self.connection.recv_streaming())
        )
        await asyncio.sleep(0)  # let the event loop start recv_streaming_task
        self.addCleanup(recv_streaming_task.cancel)

        with self.assertRaises(ConcurrencyError) as raised:
            await self.connection.recv()
        self.assertEqual(
            str(raised.exception),
            "cannot call recv while another coroutine "
            "is already running recv or recv_streaming",
        )

    async def test_recv_cancellation_before_receiving(self):
        """recv can be canceled before receiving a frame."""
        recv_task = asyncio.create_task(self.connection.recv())
        await asyncio.sleep(0)  # let the event loop start recv_task

        recv_task.cancel()
        await asyncio.sleep(0)  # let the event loop cancel recv_task

        # Running recv again receives the next message.
        await self.remote_connection.send("😀")
        self.assertEqual(await self.connection.recv(), "😀")

    async def test_recv_cancellation_while_receiving(self):
        """recv cannot be canceled after receiving a frame."""
        recv_task = asyncio.create_task(self.connection.recv())
        await asyncio.sleep(0)  # let the event loop start recv_task

        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate
            yield "⌛️"

        asyncio.create_task(self.remote_connection.send(fragments()))
        await asyncio.sleep(MS)

        recv_task.cancel()
        await asyncio.sleep(0)  # let the event loop cancel recv_task

        # Running recv again receives the complete message.
        gate.set_result(None)
        self.assertEqual(await self.connection.recv(), "⏳⌛️")

    # Test recv_streaming.

    async def test_recv_streaming_text(self):
        """recv_streaming receives a text message."""
        await self.remote_connection.send("😀")
        self.assertEqual(
            await alist(self.connection.recv_streaming()),
            ["😀"],
        )

    async def test_recv_streaming_binary(self):
        """recv_streaming receives a binary message."""
        await self.remote_connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(
            await alist(self.connection.recv_streaming()),
            [b"\x01\x02\xfe\xff"],
        )

    async def test_recv_streaming_text_as_bytes(self):
        """recv_streaming receives a text message as bytes."""
        await self.remote_connection.send("😀")
        self.assertEqual(
            await alist(self.connection.recv_streaming(decode=False)),
            ["😀".encode()],
        )

    async def test_recv_streaming_binary_as_str(self):
        """recv_streaming receives a binary message as a str."""
        await self.remote_connection.send("😀".encode())
        self.assertEqual(
            await alist(self.connection.recv_streaming(decode=True)),
            ["😀"],
        )

    async def test_recv_streaming_fragmented_text(self):
        """recv_streaming receives a fragmented text message."""
        await self.remote_connection.send(["😀", "😀"])
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_recv_streaming_fragmented_binary(self):
        """recv_streaming receives a fragmented binary message."""
        await self.remote_connection.send([b"\x01\x02", b"\xfe\xff"])
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.connection.recv_streaming()),
            [b"\x01\x02", b"\xfe\xff", b""],
        )

    async def test_recv_streaming_connection_closed_ok(self):
        """recv_streaming raises ConnectionClosedOK after a normal closure."""
        await self.remote_connection.close()
        with self.assertRaises(ConnectionClosedOK):
            async for _ in self.connection.recv_streaming():
                self.fail("did not raise")

    async def test_recv_streaming_connection_closed_error(self):
        """recv_streaming raises ConnectionClosedError after an error."""
        await self.remote_connection.close(code=CloseCode.INTERNAL_ERROR)
        with self.assertRaises(ConnectionClosedError):
            async for _ in self.connection.recv_streaming():
                self.fail("did not raise")

    async def test_recv_streaming_non_utf8_text(self):
        """recv_streaming receives a non-UTF-8 text message."""
        await self.remote_connection.send(b"\x01\x02\xfe\xff", text=True)
        with self.assertRaises(ConnectionClosedError):
            await alist(self.connection.recv_streaming())
        await self.assertFrameSent(
            Frame(Opcode.CLOSE, b"\x03\xefinvalid start byte at position 2")
        )

    async def test_recv_streaming_during_recv(self):
        """recv_streaming raises ConcurrencyError when called concurrently with recv."""
        recv_task = asyncio.create_task(self.connection.recv())
        await asyncio.sleep(0)  # let the event loop start recv_task
        self.addCleanup(recv_task.cancel)

        with self.assertRaises(ConcurrencyError) as raised:
            async for _ in self.connection.recv_streaming():
                self.fail("did not raise")
        self.assertEqual(
            str(raised.exception),
            "cannot call recv_streaming while another coroutine "
            "is already running recv or recv_streaming",
        )

    async def test_recv_streaming_during_recv_streaming(self):
        """recv_streaming raises ConcurrencyError when called concurrently."""
        recv_streaming_task = asyncio.create_task(
            alist(self.connection.recv_streaming())
        )
        await asyncio.sleep(0)  # let the event loop start recv_streaming_task
        self.addCleanup(recv_streaming_task.cancel)

        with self.assertRaises(ConcurrencyError) as raised:
            async for _ in self.connection.recv_streaming():
                self.fail("did not raise")
        self.assertEqual(
            str(raised.exception),
            r"cannot call recv_streaming while another coroutine "
            r"is already running recv or recv_streaming",
        )

    async def test_recv_streaming_cancellation_before_receiving(self):
        """recv_streaming can be canceled before receiving a frame."""
        recv_streaming_task = asyncio.create_task(
            alist(self.connection.recv_streaming())
        )
        await asyncio.sleep(0)  # let the event loop start recv_streaming_task

        recv_streaming_task.cancel()
        await asyncio.sleep(0)  # let the event loop cancel recv_streaming_task

        # Running recv_streaming again receives the next message.
        await self.remote_connection.send(["😀", "😀"])
        self.assertEqual(
            await alist(self.connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_recv_streaming_cancellation_while_receiving(self):
        """recv_streaming cannot be canceled after receiving a frame."""
        recv_streaming_task = asyncio.create_task(
            alist(self.connection.recv_streaming())
        )
        await asyncio.sleep(0)  # let the event loop start recv_streaming_task

        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate
            yield "⌛️"

        asyncio.create_task(self.remote_connection.send(fragments()))
        await asyncio.sleep(MS)

        recv_streaming_task.cancel()
        await asyncio.sleep(0)  # let the event loop cancel recv_streaming_task

        gate.set_result(None)
        # Running recv_streaming again fails.
        with self.assertRaises(ConcurrencyError):
            await alist(self.connection.recv_streaming())

    # Test send.

    async def test_send_text(self):
        """send sends a text message."""
        await self.connection.send("😀")
        self.assertEqual(await self.remote_connection.recv(), "😀")

    async def test_send_binary(self):
        """send sends a binary message."""
        await self.connection.send(b"\x01\x02\xfe\xff")
        self.assertEqual(await self.remote_connection.recv(), b"\x01\x02\xfe\xff")

    async def test_send_binary_from_str(self):
        """send sends a binary message from a str."""
        await self.connection.send("😀", text=False)
        self.assertEqual(await self.remote_connection.recv(), "😀".encode())

    async def test_send_text_from_bytes(self):
        """send sends a text message from bytes."""
        await self.connection.send("😀".encode(), text=True)
        self.assertEqual(await self.remote_connection.recv(), "😀")

    async def test_send_fragmented_text(self):
        """send sends a fragmented text message."""
        await self.connection.send(["😀", "😀"])
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_send_fragmented_binary(self):
        """send sends a fragmented binary message."""
        await self.connection.send([b"\x01\x02", b"\xfe\xff"])
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            [b"\x01\x02", b"\xfe\xff", b""],
        )

    async def test_send_fragmented_binary_from_str(self):
        """send sends a fragmented binary message from a str."""
        await self.connection.send(["😀", "😀"], text=False)
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀".encode(), "😀".encode(), b""],
        )

    async def test_send_fragmented_text_from_bytes(self):
        """send sends a fragmented text message from bytes."""
        await self.connection.send(["😀".encode(), "😀".encode()], text=True)
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_send_async_fragmented_text(self):
        """send sends a fragmented text message asynchronously."""

        async def fragments():
            yield "😀"
            yield "😀"

        await self.connection.send(fragments())
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_send_async_fragmented_binary(self):
        """send sends a fragmented binary message asynchronously."""

        async def fragments():
            yield b"\x01\x02"
            yield b"\xfe\xff"

        await self.connection.send(fragments())
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            [b"\x01\x02", b"\xfe\xff", b""],
        )

    async def test_send_async_fragmented_binary_from_str(self):
        """send sends a fragmented binary message from a str asynchronously."""

        async def fragments():
            yield "😀"
            yield "😀"

        await self.connection.send(fragments(), text=False)
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀".encode(), "😀".encode(), b""],
        )

    async def test_send_async_fragmented_text_from_bytes(self):
        """send sends a fragmented text message from bytes asynchronously."""

        async def fragments():
            yield "😀".encode()
            yield "😀".encode()

        await self.connection.send(fragments(), text=True)
        # websockets sends an trailing empty fragment. That's an implementation detail.
        self.assertEqual(
            await alist(self.remote_connection.recv_streaming()),
            ["😀", "😀", ""],
        )

    async def test_send_connection_closed_ok(self):
        """send raises ConnectionClosedOK after a normal closure."""
        await self.remote_connection.close()
        with self.assertRaises(ConnectionClosedOK):
            await self.connection.send("😀")

    async def test_send_connection_closed_error(self):
        """send raises ConnectionClosedError after an error."""
        await self.remote_connection.close(code=CloseCode.INTERNAL_ERROR)
        with self.assertRaises(ConnectionClosedError):
            await self.connection.send("😀")

    async def test_send_while_send_blocked(self):
        """send waits for a previous call to send to complete."""
        # This test fails if the guard with fragmented_send_waiter is removed
        # from send() in the case when message is an Iterable.
        self.connection.pause_writing()
        asyncio.create_task(self.connection.send(["⏳", "⌛️"]))
        await asyncio.sleep(MS)
        await self.assertFrameSent(
            Frame(Opcode.TEXT, "⏳".encode(), fin=False),
        )

        asyncio.create_task(self.connection.send("✅"))
        await asyncio.sleep(MS)
        await self.assertNoFrameSent()

        self.connection.resume_writing()
        await asyncio.sleep(MS)
        await self.assertFramesSent(
            [
                Frame(Opcode.CONT, "⌛️".encode(), fin=False),
                Frame(Opcode.CONT, b"", fin=True),
                Frame(Opcode.TEXT, "✅".encode()),
            ]
        )

    async def test_send_while_send_async_blocked(self):
        """send waits for a previous call to send to complete."""
        # This test fails if the guard with fragmented_send_waiter is removed
        # from send() in the case when message is an AsyncIterable.
        self.connection.pause_writing()

        async def fragments():
            yield "⏳"
            yield "⌛️"

        asyncio.create_task(self.connection.send(fragments()))
        await asyncio.sleep(MS)
        await self.assertFrameSent(
            Frame(Opcode.TEXT, "⏳".encode(), fin=False),
        )

        asyncio.create_task(self.connection.send("✅"))
        await asyncio.sleep(MS)
        await self.assertNoFrameSent()

        self.connection.resume_writing()
        await asyncio.sleep(MS)
        await self.assertFramesSent(
            [
                Frame(Opcode.CONT, "⌛️".encode(), fin=False),
                Frame(Opcode.CONT, b"", fin=True),
                Frame(Opcode.TEXT, "✅".encode()),
            ]
        )

    async def test_send_during_send_async(self):
        """send waits for a previous call to send to complete."""
        # This test fails if the guard with fragmented_send_waiter is removed
        # from send() in the case when message is an AsyncIterable.
        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate
            yield "⌛️"

        asyncio.create_task(self.connection.send(fragments()))
        await asyncio.sleep(MS)
        await self.assertFrameSent(
            Frame(Opcode.TEXT, "⏳".encode(), fin=False),
        )

        asyncio.create_task(self.connection.send("✅"))
        await asyncio.sleep(MS)
        await self.assertNoFrameSent()

        gate.set_result(None)
        await asyncio.sleep(MS)
        await self.assertFramesSent(
            [
                Frame(Opcode.CONT, "⌛️".encode(), fin=False),
                Frame(Opcode.CONT, b"", fin=True),
                Frame(Opcode.TEXT, "✅".encode()),
            ]
        )

    async def test_send_empty_iterable(self):
        """send does nothing when called with an empty iterable."""
        await self.connection.send([])
        await self.connection.close()
        self.assertEqual(await alist(self.remote_connection), [])

    async def test_send_mixed_iterable(self):
        """send raises TypeError when called with an iterable of inconsistent types."""
        with self.assertRaises(TypeError):
            await self.connection.send(["😀", b"\xfe\xff"])

    async def test_send_unsupported_iterable(self):
        """send raises TypeError when called with an iterable of unsupported type."""
        with self.assertRaises(TypeError):
            await self.connection.send([None])

    async def test_send_empty_async_iterable(self):
        """send does nothing when called with an empty async iterable."""

        async def fragments():
            return
            yield  # pragma: no cover

        await self.connection.send(fragments())
        await self.connection.close()
        self.assertEqual(await alist(self.remote_connection), [])

    async def test_send_mixed_async_iterable(self):
        """send raises TypeError when called with an iterable of inconsistent types."""

        async def fragments():
            yield "😀"
            yield b"\xfe\xff"

        with self.assertRaises(TypeError):
            await self.connection.send(fragments())

    async def test_send_unsupported_async_iterable(self):
        """send raises TypeError when called with an iterable of unsupported type."""

        async def fragments():
            yield None

        with self.assertRaises(TypeError):
            await self.connection.send(fragments())

    async def test_send_dict(self):
        """send raises TypeError when called with a dict."""
        with self.assertRaises(TypeError):
            await self.connection.send({"type": "object"})

    async def test_send_unsupported_type(self):
        """send raises TypeError when called with an unsupported type."""
        with self.assertRaises(TypeError):
            await self.connection.send(None)

    # Test close.

    async def test_close(self):
        """close sends a close frame."""
        await self.connection.close()
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe8"))

    async def test_close_explicit_code_reason(self):
        """close sends a close frame with a given code and reason."""
        await self.connection.close(CloseCode.GOING_AWAY, "bye!")
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe9bye!"))

    async def test_close_waits_for_close_frame(self):
        """close waits for a close frame (then EOF) before returning."""
        async with self.delay_frames_rcvd(MS), self.delay_eof_rcvd(MS):
            await self.connection.close()

        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_waits_for_connection_closed(self):
        """close waits for EOF before returning."""
        if self.LOCAL is SERVER:
            self.skipTest("only relevant on the client-side")

        async with self.delay_eof_rcvd(MS):
            await self.connection.close()

        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_no_timeout_waits_for_close_frame(self):
        """close without timeout waits for a close frame (then EOF) before returning."""
        self.connection.close_timeout = None

        async with self.delay_frames_rcvd(MS), self.delay_eof_rcvd(MS):
            await self.connection.close()

        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_no_timeout_waits_for_connection_closed(self):
        """close without timeout waits for EOF before returning."""
        if self.LOCAL is SERVER:
            self.skipTest("only relevant on the client-side")

        self.connection.close_timeout = None

        async with self.delay_eof_rcvd(MS):
            await self.connection.close()

        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_timeout_waiting_for_close_frame(self):
        """close times out if no close frame is received."""
        async with self.drop_eof_rcvd(), self.drop_frames_rcvd():
            await self.connection.close()

        with self.assertRaises(ConnectionClosedError) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); no close frame received")
        self.assertIsInstance(exc.__cause__, TimeoutError)

    async def test_close_timeout_waiting_for_connection_closed(self):
        """close times out if EOF isn't received."""
        if self.LOCAL is SERVER:
            self.skipTest("only relevant on the client-side")

        async with self.drop_eof_rcvd():
            await self.connection.close()

        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        # Remove socket.timeout when dropping Python < 3.10.
        self.assertIsInstance(exc.__cause__, (socket.timeout, TimeoutError))

    async def test_close_preserves_queued_messages(self):
        """close preserves messages buffered in the assembler."""
        await self.remote_connection.send("😀")
        await self.connection.close()

        self.assertEqual(await self.connection.recv(), "😀")
        with self.assertRaises(ConnectionClosedOK) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_idempotency(self):
        """close does nothing if the connection is already closed."""
        await self.connection.close()
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe8"))

        await self.connection.close()
        await self.assertNoFrameSent()

    async def test_close_during_recv(self):
        """close aborts recv when called concurrently with recv."""
        recv_task = asyncio.create_task(self.connection.recv())
        await asyncio.sleep(MS)
        await self.connection.close()
        with self.assertRaises(ConnectionClosedOK) as raised:
            await recv_task

        exc = raised.exception
        self.assertEqual(str(exc), "sent 1000 (OK); then received 1000 (OK)")
        self.assertIsNone(exc.__cause__)

    async def test_close_during_send(self):
        """close fails the connection when called concurrently with send."""
        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate
            yield "⌛️"

        send_task = asyncio.create_task(self.connection.send(fragments()))
        await asyncio.sleep(MS)

        asyncio.create_task(self.connection.close())
        await asyncio.sleep(MS)

        gate.set_result(None)

        with self.assertRaises(ConnectionClosedError) as raised:
            await send_task

        exc = raised.exception
        self.assertEqual(
            str(exc),
            "sent 1011 (internal error) close during fragmented message; "
            "no close frame received",
        )
        self.assertIsNone(exc.__cause__)

    # Test wait_closed.

    async def test_wait_closed(self):
        """wait_closed waits for the connection to close."""
        wait_closed_task = asyncio.create_task(self.connection.wait_closed())
        await asyncio.sleep(0)  # let the event loop start wait_closed_task
        self.assertFalse(wait_closed_task.done())
        await self.connection.close()
        self.assertTrue(wait_closed_task.done())

    # Test ping.

    @patch("random.getrandbits", return_value=1918987876)
    async def test_ping(self, getrandbits):
        """ping sends a ping frame with a random payload."""
        await self.connection.ping()
        getrandbits.assert_called_once_with(32)
        await self.assertFrameSent(Frame(Opcode.PING, b"rand"))

    async def test_ping_explicit_text(self):
        """ping sends a ping frame with a payload provided as text."""
        await self.connection.ping("ping")
        await self.assertFrameSent(Frame(Opcode.PING, b"ping"))

    async def test_ping_explicit_binary(self):
        """ping sends a ping frame with a payload provided as binary."""
        await self.connection.ping(b"ping")
        await self.assertFrameSent(Frame(Opcode.PING, b"ping"))

    async def test_acknowledge_ping(self):
        """ping is acknowledged by a pong with the same payload."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("this")
        await self.remote_connection.pong("this")
        async with asyncio_timeout(MS):
            await pong_waiter

    async def test_acknowledge_canceled_ping(self):
        """ping is acknowledged by a pong with the same payload after being canceled."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("this")
        pong_waiter.cancel()
        await self.remote_connection.pong("this")
        with self.assertRaises(asyncio.CancelledError):
            await pong_waiter

    async def test_acknowledge_ping_non_matching_pong(self):
        """ping isn't acknowledged by a pong with a different payload."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("this")
        await self.remote_connection.pong("that")
        with self.assertRaises(TimeoutError):
            async with asyncio_timeout(MS):
                await pong_waiter

    async def test_acknowledge_previous_ping(self):
        """ping is acknowledged by a pong for a later ping."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("this")
            await self.connection.ping("that")
        await self.remote_connection.pong("that")
        async with asyncio_timeout(MS):
            await pong_waiter

    async def test_acknowledge_previous_canceled_ping(self):
        """ping is acknowledged by a pong for a later ping after being canceled."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("this")
            pong_waiter_2 = await self.connection.ping("that")
        pong_waiter.cancel()
        await self.remote_connection.pong("that")
        async with asyncio_timeout(MS):
            await pong_waiter_2
        with self.assertRaises(asyncio.CancelledError):
            await pong_waiter

    async def test_ping_duplicate_payload(self):
        """ping rejects the same payload until receiving the pong."""
        async with self.drop_frames_rcvd():  # drop automatic response to ping
            pong_waiter = await self.connection.ping("idem")

        with self.assertRaises(ConcurrencyError) as raised:
            await self.connection.ping("idem")
        self.assertEqual(
            str(raised.exception),
            "already waiting for a pong with the same data",
        )

        await self.remote_connection.pong("idem")
        async with asyncio_timeout(MS):
            await pong_waiter

        await self.connection.ping("idem")  # doesn't raise an exception

    async def test_ping_unsupported_type(self):
        """ping raises TypeError when called with an unsupported type."""
        with self.assertRaises(TypeError):
            await self.connection.ping([])

    # Test pong.

    async def test_pong(self):
        """pong sends a pong frame."""
        await self.connection.pong()
        await self.assertFrameSent(Frame(Opcode.PONG, b""))

    async def test_pong_explicit_text(self):
        """pong sends a pong frame with a payload provided as text."""
        await self.connection.pong("pong")
        await self.assertFrameSent(Frame(Opcode.PONG, b"pong"))

    async def test_pong_explicit_binary(self):
        """pong sends a pong frame with a payload provided as binary."""
        await self.connection.pong(b"pong")
        await self.assertFrameSent(Frame(Opcode.PONG, b"pong"))

    async def test_pong_unsupported_type(self):
        """pong raises TypeError when called with an unsupported type."""
        with self.assertRaises(TypeError):
            await self.connection.pong([])

    # Test keepalive.

    @patch("random.getrandbits", return_value=1918987876)
    async def test_keepalive(self, getrandbits):
        """keepalive sends pings at ping_interval and measures latency."""
        self.connection.ping_interval = 3 * MS
        self.connection.start_keepalive()
        self.assertIsNotNone(self.connection.keepalive_task)
        self.assertEqual(self.connection.latency, 0)
        # 3 ms: keepalive() sends a ping frame.
        # 3.x ms: a pong frame is received.
        await asyncio.sleep(4 * MS)
        # 4 ms: check that the ping frame was sent.
        await self.assertFrameSent(Frame(Opcode.PING, b"rand"))
        self.assertGreater(self.connection.latency, 0)
        self.assertLess(self.connection.latency, MS)

    async def test_disable_keepalive(self):
        """keepalive is disabled when ping_interval is None."""
        self.connection.ping_interval = None
        self.connection.start_keepalive()
        self.assertIsNone(self.connection.keepalive_task)

    @patch("random.getrandbits", return_value=1918987876)
    async def test_keepalive_times_out(self, getrandbits):
        """keepalive closes the connection if ping_timeout elapses."""
        self.connection.ping_interval = 4 * MS
        self.connection.ping_timeout = 2 * MS
        async with self.drop_frames_rcvd():
            self.connection.start_keepalive()
            # 4 ms: keepalive() sends a ping frame.
            await asyncio.sleep(4 * MS)
            # Exiting the context manager sleeps for 1 ms.
            # 4.x ms: a pong frame is dropped.
        # 6 ms: no pong frame is received; the connection is closed.
        await asyncio.sleep(2 * MS)
        # 7 ms: check that the connection is closed.
        self.assertEqual(self.connection.state, State.CLOSED)

    @patch("random.getrandbits", return_value=1918987876)
    async def test_keepalive_ignores_timeout(self, getrandbits):
        """keepalive ignores timeouts if ping_timeout isn't set."""
        self.connection.ping_interval = 4 * MS
        self.connection.ping_timeout = None
        async with self.drop_frames_rcvd():
            self.connection.start_keepalive()
            # 4 ms: keepalive() sends a ping frame.
            # 4.x ms: a pong frame is dropped.
            await asyncio.sleep(4 * MS)
            # Exiting the context manager sleeps for 1 ms.
        # 6 ms: no pong frame is received; the connection remains open.
        await asyncio.sleep(2 * MS)
        # 7 ms: check that the connection is still open.
        self.assertEqual(self.connection.state, State.OPEN)

    async def test_keepalive_terminates_while_sleeping(self):
        """keepalive task terminates while waiting to send a ping."""
        self.connection.ping_interval = 3 * MS
        self.connection.start_keepalive()
        await asyncio.sleep(MS)
        await self.connection.close()
        self.assertTrue(self.connection.keepalive_task.done())

    async def test_keepalive_terminates_while_waiting_for_pong(self):
        """keepalive task terminates while waiting to receive a pong."""
        self.connection.ping_interval = MS
        self.connection.ping_timeout = 3 * MS
        async with self.drop_frames_rcvd():
            self.connection.start_keepalive()
            # 1 ms: keepalive() sends a ping frame.
            # 1.x ms: a pong frame is dropped.
            await asyncio.sleep(MS)
            # Exiting the context manager sleeps for 1 ms.
        # 2 ms: close the connection before ping_timeout elapses.
        await self.connection.close()
        self.assertTrue(self.connection.keepalive_task.done())

    async def test_keepalive_reports_errors(self):
        """keepalive reports unexpected errors in logs."""
        self.connection.ping_interval = 2 * MS
        async with self.drop_frames_rcvd():
            self.connection.start_keepalive()
            # 2 ms: keepalive() sends a ping frame.
            # 2.x ms: a pong frame is dropped.
            await asyncio.sleep(2 * MS)
            # Exiting the context manager sleeps for 1 ms.
        # 3 ms: inject a fault: raise an exception in the pending pong waiter.
        pong_waiter = next(iter(self.connection.pong_waiters.values()))[0]
        with self.assertLogs("websockets", logging.ERROR) as logs:
            pong_waiter.set_exception(Exception("BOOM"))
            await asyncio.sleep(0)
        self.assertEqual(
            [record.getMessage() for record in logs.records],
            ["keepalive ping failed"],
        )
        self.assertEqual(
            [str(record.exc_info[1]) for record in logs.records],
            ["BOOM"],
        )

    # Test parameters.

    async def test_close_timeout(self):
        """close_timeout parameter configures close timeout."""
        connection = Connection(Protocol(self.LOCAL), close_timeout=42 * MS)
        self.assertEqual(connection.close_timeout, 42 * MS)

    async def test_max_queue(self):
        """max_queue configures high-water mark of frames buffer."""
        connection = Connection(Protocol(self.LOCAL), max_queue=4)
        transport = Mock()
        connection.connection_made(transport)
        self.assertEqual(connection.recv_messages.high, 4)

    async def test_max_queue_none(self):
        """max_queue disables high-water mark of frames buffer."""
        connection = Connection(Protocol(self.LOCAL), max_queue=None)
        transport = Mock()
        connection.connection_made(transport)
        self.assertEqual(connection.recv_messages.high, None)
        self.assertEqual(connection.recv_messages.low, None)

    async def test_max_queue_tuple(self):
        """max_queue configures high-water and low-water marks of frames buffer."""
        connection = Connection(
            Protocol(self.LOCAL),
            max_queue=(4, 2),
        )
        transport = Mock()
        connection.connection_made(transport)
        self.assertEqual(connection.recv_messages.high, 4)
        self.assertEqual(connection.recv_messages.low, 2)

    async def test_write_limit(self):
        """write_limit parameter configures high-water mark of write buffer."""
        connection = Connection(
            Protocol(self.LOCAL),
            write_limit=4096,
        )
        transport = Mock()
        connection.connection_made(transport)
        transport.set_write_buffer_limits.assert_called_once_with(4096, None)

    async def test_write_limits(self):
        """write_limit parameter configures high and low-water marks of write buffer."""
        connection = Connection(
            Protocol(self.LOCAL),
            write_limit=(4096, 2048),
        )
        transport = Mock()
        connection.connection_made(transport)
        transport.set_write_buffer_limits.assert_called_once_with(4096, 2048)

    # Test attributes.

    async def test_id(self):
        """Connection has an id attribute."""
        self.assertIsInstance(self.connection.id, uuid.UUID)

    async def test_logger(self):
        """Connection has a logger attribute."""
        self.assertIsInstance(self.connection.logger, logging.LoggerAdapter)

    @patch("asyncio.BaseTransport.get_extra_info", return_value=("sock", 1234))
    async def test_local_address(self, get_extra_info):
        """Connection provides a local_address attribute."""
        self.assertEqual(self.connection.local_address, ("sock", 1234))
        get_extra_info.assert_called_with("sockname")

    @patch("asyncio.BaseTransport.get_extra_info", return_value=("peer", 1234))
    async def test_remote_address(self, get_extra_info):
        """Connection provides a remote_address attribute."""
        self.assertEqual(self.connection.remote_address, ("peer", 1234))
        get_extra_info.assert_called_with("peername")

    async def test_state(self):
        """Connection has a state attribute."""
        self.assertIs(self.connection.state, State.OPEN)

    async def test_request(self):
        """Connection has a request attribute."""
        self.assertIsNone(self.connection.request)

    async def test_response(self):
        """Connection has a response attribute."""
        self.assertIsNone(self.connection.response)

    async def test_subprotocol(self):
        """Connection has a subprotocol attribute."""
        self.assertIsNone(self.connection.subprotocol)

    async def test_close_code(self):
        """Connection has a close_code attribute."""
        self.assertIsNone(self.connection.close_code)

    async def test_close_reason(self):
        """Connection has a close_reason attribute."""
        self.assertIsNone(self.connection.close_reason)

    # Test reporting of network errors.

    async def test_writing_in_data_received_fails(self):
        """Error when responding to incoming frames is correctly reported."""
        # Inject a fault by shutting down the transport for writing — but not by
        # closing it because that would terminate the connection.
        self.transport.write_eof()
        # Receive a ping. Responding with a pong will fail.
        await self.remote_connection.ping()
        # The connection closed exception reports the injected fault.
        with self.assertRaises(ConnectionClosedError) as raised:
            await self.connection.recv()
        cause = raised.exception.__cause__
        self.assertEqual(str(cause), "Cannot call write() after write_eof()")
        self.assertIsInstance(cause, RuntimeError)

    async def test_writing_in_send_context_fails(self):
        """Error when sending outgoing frame is correctly reported."""
        # Inject a fault by shutting down the transport for writing — but not by
        # closing it because that would terminate the connection.
        self.transport.write_eof()
        # Sending a pong will fail.
        # The connection closed exception reports the injected fault.
        with self.assertRaises(ConnectionClosedError) as raised:
            await self.connection.pong()
        cause = raised.exception.__cause__
        self.assertEqual(str(cause), "Cannot call write() after write_eof()")
        self.assertIsInstance(cause, RuntimeError)

    # Test safety nets — catching all exceptions in case of bugs.

    # Inject a fault in a random call in data_received().
    # This test is tightly coupled to the implementation.
    @patch("websockets.protocol.Protocol.events_received", side_effect=AssertionError)
    async def test_unexpected_failure_in_data_received(self, events_received):
        """Unexpected internal error in data_received() is correctly reported."""
        # Receive a message to trigger the fault.
        await self.remote_connection.send("😀")

        with self.assertRaises(ConnectionClosedError) as raised:
            await self.connection.recv()

        exc = raised.exception
        self.assertEqual(str(exc), "no close frame received or sent")
        self.assertIsInstance(exc.__cause__, AssertionError)

    # Inject a fault in a random call in send_context().
    # This test is tightly coupled to the implementation.
    @patch("websockets.protocol.Protocol.send_text", side_effect=AssertionError)
    async def test_unexpected_failure_in_send_context(self, send_text):
        """Unexpected internal error in send_context() is correctly reported."""
        # Send a message to trigger the fault.
        # The connection closed exception reports the injected fault.
        with self.assertRaises(ConnectionClosedError) as raised:
            await self.connection.send("😀")

        exc = raised.exception
        self.assertEqual(str(exc), "no close frame received or sent")
        self.assertIsInstance(exc.__cause__, AssertionError)

    # Test broadcast.

    async def test_broadcast_text(self):
        """broadcast broadcasts a text message."""
        broadcast([self.connection], "😀")
        await self.assertFrameSent(Frame(Opcode.TEXT, "😀".encode()))

    @unittest.skipIf(
        sys.version_info[:2] < (3, 11),
        "raise_exceptions requires Python 3.11+",
    )
    async def test_broadcast_text_reports_no_errors(self):
        """broadcast broadcasts a text message without raising exceptions."""
        broadcast([self.connection], "😀", raise_exceptions=True)
        await self.assertFrameSent(Frame(Opcode.TEXT, "😀".encode()))

    async def test_broadcast_binary(self):
        """broadcast broadcasts a binary message."""
        broadcast([self.connection], b"\x01\x02\xfe\xff")
        await self.assertFrameSent(Frame(Opcode.BINARY, b"\x01\x02\xfe\xff"))

    @unittest.skipIf(
        sys.version_info[:2] < (3, 11),
        "raise_exceptions requires Python 3.11+",
    )
    async def test_broadcast_binary_reports_no_errors(self):
        """broadcast broadcasts a binary message without raising exceptions."""
        broadcast([self.connection], b"\x01\x02\xfe\xff", raise_exceptions=True)
        await self.assertFrameSent(Frame(Opcode.BINARY, b"\x01\x02\xfe\xff"))

    async def test_broadcast_no_clients(self):
        """broadcast does nothing when called with an empty list of clients."""
        broadcast([], "😀")
        await self.assertNoFrameSent()

    async def test_broadcast_two_clients(self):
        """broadcast broadcasts a message to several clients."""
        broadcast([self.connection, self.connection], "😀")
        await self.assertFramesSent(
            [
                Frame(Opcode.TEXT, "😀".encode()),
                Frame(Opcode.TEXT, "😀".encode()),
            ]
        )

    async def test_broadcast_skips_closed_connection(self):
        """broadcast ignores closed connections."""
        await self.connection.close()
        await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe8"))

        with self.assertNoLogs("websockets", logging.WARNING):
            broadcast([self.connection], "😀")
        await self.assertNoFrameSent()

    async def test_broadcast_skips_closing_connection(self):
        """broadcast ignores closing connections."""
        async with self.delay_frames_rcvd(MS):
            close_task = asyncio.create_task(self.connection.close())
            await asyncio.sleep(0)
            await self.assertFrameSent(Frame(Opcode.CLOSE, b"\x03\xe8"))

            with self.assertNoLogs("websockets", logging.WARNING):
                broadcast([self.connection], "😀")
            await self.assertNoFrameSent()

        await close_task

    async def test_broadcast_skips_connection_with_send_blocked(self):
        """broadcast logs a warning when a connection is blocked in send."""
        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate

        send_task = asyncio.create_task(self.connection.send(fragments()))
        await asyncio.sleep(MS)
        await self.assertFrameSent(Frame(Opcode.TEXT, "⏳".encode(), fin=False))

        with self.assertLogs("websockets", logging.WARNING) as logs:
            broadcast([self.connection], "😀")

        self.assertEqual(
            [record.getMessage() for record in logs.records],
            ["skipped broadcast: sending a fragmented message"],
        )

        gate.set_result(None)
        await send_task

    @unittest.skipIf(
        sys.version_info[:2] < (3, 11),
        "raise_exceptions requires Python 3.11+",
    )
    async def test_broadcast_reports_connection_with_send_blocked(self):
        """broadcast raises exceptions for connections blocked in send."""
        gate = asyncio.get_running_loop().create_future()

        async def fragments():
            yield "⏳"
            await gate

        send_task = asyncio.create_task(self.connection.send(fragments()))
        await asyncio.sleep(MS)
        await self.assertFrameSent(Frame(Opcode.TEXT, "⏳".encode(), fin=False))

        with self.assertRaises(ExceptionGroup) as raised:
            broadcast([self.connection], "😀", raise_exceptions=True)

        self.assertEqual(str(raised.exception), "skipped broadcast (1 sub-exception)")
        exc = raised.exception.exceptions[0]
        self.assertEqual(str(exc), "sending a fragmented message")
        self.assertIsInstance(exc, ConcurrencyError)

        gate.set_result(None)
        await send_task

    async def test_broadcast_skips_connection_failing_to_send(self):
        """broadcast logs a warning when a connection fails to send."""
        # Inject a fault by shutting down the transport for writing.
        self.transport.write_eof()

        with self.assertLogs("websockets", logging.WARNING) as logs:
            broadcast([self.connection], "😀")

        self.assertEqual(
            [record.getMessage() for record in logs.records],
            [
                "skipped broadcast: failed to write message: "
                "RuntimeError: Cannot call write() after write_eof()"
            ],
        )

    @unittest.skipIf(
        sys.version_info[:2] < (3, 11),
        "raise_exceptions requires Python 3.11+",
    )
    async def test_broadcast_reports_connection_failing_to_send(self):
        """broadcast raises exceptions for connections failing to send."""
        # Inject a fault by shutting down the transport for writing.
        self.transport.write_eof()

        with self.assertRaises(ExceptionGroup) as raised:
            broadcast([self.connection], "😀", raise_exceptions=True)

        self.assertEqual(str(raised.exception), "skipped broadcast (1 sub-exception)")
        exc = raised.exception.exceptions[0]
        self.assertEqual(str(exc), "failed to write message")
        self.assertIsInstance(exc, RuntimeError)
        cause = exc.__cause__
        self.assertEqual(str(cause), "Cannot call write() after write_eof()")
        self.assertIsInstance(cause, RuntimeError)

    async def test_broadcast_type_error(self):
        """broadcast raises TypeError when called with an unsupported type."""
        with self.assertRaises(TypeError):
            broadcast([self.connection], ["⏳", "⌛️"])


class ServerConnectionTests(ClientConnectionTests):
    LOCAL = SERVER
    REMOTE = CLIENT