Update 2025-04-13_16:26:04

venv/lib/python3.11/site-packages/h11/tests/data/test-file

@@ -0,0 +1 @@
+92b12bc045050b55b848d37167a1a63947c364579889ce1d39788e45e9fac9e5

venv/lib/python3.11/site-packages/h11/tests/helpers.py

@@ -0,0 +1,101 @@
+from typing import cast, List, Type, Union, ValuesView
+
+from .._connection import Connection, NEED_DATA, PAUSED
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._state import CLIENT, CLOSED, DONE, MUST_CLOSE, SERVER
+from .._util import Sentinel
+
+try:
+    from typing import Literal
+except ImportError:
+    from typing_extensions import Literal  # type: ignore
+
+
+def get_all_events(conn: Connection) -> List[Event]:
+    got_events = []
+    while True:
+        event = conn.next_event()
+        if event in (NEED_DATA, PAUSED):
+            break
+        event = cast(Event, event)
+        got_events.append(event)
+        if type(event) is ConnectionClosed:
+            break
+    return got_events
+
+
+def receive_and_get(conn: Connection, data: bytes) -> List[Event]:
+    conn.receive_data(data)
+    return get_all_events(conn)
+
+
+# Merges adjacent Data events, converts payloads to bytestrings, and removes
+# chunk boundaries.
+def normalize_data_events(in_events: List[Event]) -> List[Event]:
+    out_events: List[Event] = []
+    for event in in_events:
+        if type(event) is Data:
+            event = Data(data=bytes(event.data), chunk_start=False, chunk_end=False)
+        if out_events and type(out_events[-1]) is type(event) is Data:
+            out_events[-1] = Data(
+                data=out_events[-1].data + event.data,
+                chunk_start=out_events[-1].chunk_start,
+                chunk_end=out_events[-1].chunk_end,
+            )
+        else:
+            out_events.append(event)
+    return out_events
+
+
+# Given that we want to write tests that push some events through a Connection
+# and check that its state updates appropriately... we might as make a habit
+# of pushing them through two Connections with a fake network link in
+# between.
+class ConnectionPair:
+    def __init__(self) -> None:
+        self.conn = {CLIENT: Connection(CLIENT), SERVER: Connection(SERVER)}
+        self.other = {CLIENT: SERVER, SERVER: CLIENT}
+
+    @property
+    def conns(self) -> ValuesView[Connection]:
+        return self.conn.values()
+
+    # expect="match" if expect=send_events; expect=[...] to say what expected
+    def send(
+        self,
+        role: Type[Sentinel],
+        send_events: Union[List[Event], Event],
+        expect: Union[List[Event], Event, Literal["match"]] = "match",
+    ) -> bytes:
+        if not isinstance(send_events, list):
+            send_events = [send_events]
+        data = b""
+        closed = False
+        for send_event in send_events:
+            new_data = self.conn[role].send(send_event)
+            if new_data is None:
+                closed = True
+            else:
+                data += new_data
+        # send uses b"" to mean b"", and None to mean closed
+        # receive uses b"" to mean closed, and None to mean "try again"
+        # so we have to translate between the two conventions
+        if data:
+            self.conn[self.other[role]].receive_data(data)
+        if closed:
+            self.conn[self.other[role]].receive_data(b"")
+        got_events = get_all_events(self.conn[self.other[role]])
+        if expect == "match":
+            expect = send_events
+        if not isinstance(expect, list):
+            expect = [expect]
+        assert got_events == expect
+        return data

venv/lib/python3.11/site-packages/h11/tests/test_against_stdlib_http.py

@@ -0,0 +1,115 @@
+import json
+import os.path
+import socket
+import socketserver
+import threading
+from contextlib import closing, contextmanager
+from http.server import SimpleHTTPRequestHandler
+from typing import Callable, Generator
+from urllib.request import urlopen
+
+import h11
+
+
+@contextmanager
+def socket_server(
+    handler: Callable[..., socketserver.BaseRequestHandler]
+) -> Generator[socketserver.TCPServer, None, None]:
+    httpd = socketserver.TCPServer(("127.0.0.1", 0), handler)
+    thread = threading.Thread(
+        target=httpd.serve_forever, kwargs={"poll_interval": 0.01}
+    )
+    thread.daemon = True
+    try:
+        thread.start()
+        yield httpd
+    finally:
+        httpd.shutdown()
+
+
+test_file_path = os.path.join(os.path.dirname(__file__), "data/test-file")
+with open(test_file_path, "rb") as f:
+    test_file_data = f.read()
+
+
+class SingleMindedRequestHandler(SimpleHTTPRequestHandler):
+    def translate_path(self, path: str) -> str:
+        return test_file_path
+
+
+def test_h11_as_client() -> None:
+    with socket_server(SingleMindedRequestHandler) as httpd:
+        with closing(socket.create_connection(httpd.server_address)) as s:
+            c = h11.Connection(h11.CLIENT)
+
+            s.sendall(
+                c.send(  # type: ignore[arg-type]
+                    h11.Request(
+                        method="GET", target="/foo", headers=[("Host", "localhost")]
+                    )
+                )
+            )
+            s.sendall(c.send(h11.EndOfMessage()))  # type: ignore[arg-type]
+
+            data = bytearray()
+            while True:
+                event = c.next_event()
+                print(event)
+                if event is h11.NEED_DATA:
+                    # Use a small read buffer to make things more challenging
+                    # and exercise more paths :-)
+                    c.receive_data(s.recv(10))
+                    continue
+                if type(event) is h11.Response:
+                    assert event.status_code == 200
+                if type(event) is h11.Data:
+                    data += event.data
+                if type(event) is h11.EndOfMessage:
+                    break
+            assert bytes(data) == test_file_data
+
+
+class H11RequestHandler(socketserver.BaseRequestHandler):
+    def handle(self) -> None:
+        with closing(self.request) as s:
+            c = h11.Connection(h11.SERVER)
+            request = None
+            while True:
+                event = c.next_event()
+                if event is h11.NEED_DATA:
+                    # Use a small read buffer to make things more challenging
+                    # and exercise more paths :-)
+                    c.receive_data(s.recv(10))
+                    continue
+                if type(event) is h11.Request:
+                    request = event
+                if type(event) is h11.EndOfMessage:
+                    break
+            assert request is not None
+            info = json.dumps(
+                {
+                    "method": request.method.decode("ascii"),
+                    "target": request.target.decode("ascii"),
+                    "headers": {
+                        name.decode("ascii"): value.decode("ascii")
+                        for (name, value) in request.headers
+                    },
+                }
+            )
+            s.sendall(c.send(h11.Response(status_code=200, headers=[])))  # type: ignore[arg-type]
+            s.sendall(c.send(h11.Data(data=info.encode("ascii"))))
+            s.sendall(c.send(h11.EndOfMessage()))
+
+
+def test_h11_as_server() -> None:
+    with socket_server(H11RequestHandler) as httpd:
+        host, port = httpd.server_address
+        url = "http://{}:{}/some-path".format(host, port)
+        with closing(urlopen(url)) as f:
+            assert f.getcode() == 200
+            data = f.read()
+    info = json.loads(data.decode("ascii"))
+    print(info)
+    assert info["method"] == "GET"
+    assert info["target"] == "/some-path"
+    assert "urllib" in info["headers"]["user-agent"]

venv/lib/python3.11/site-packages/h11/tests/test_events.py

@@ -0,0 +1,150 @@
+from http import HTTPStatus
+
+import pytest
+
+from .. import _events
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._util import LocalProtocolError
+
+
+def test_events() -> None:
+    with pytest.raises(LocalProtocolError):
+        # Missing Host:
+        req = Request(
+            method="GET", target="/", headers=[("a", "b")], http_version="1.1"
+        )
+    # But this is okay (HTTP/1.0)
+    req = Request(method="GET", target="/", headers=[("a", "b")], http_version="1.0")
+    # fields are normalized
+    assert req.method == b"GET"
+    assert req.target == b"/"
+    assert req.headers == [(b"a", b"b")]
+    assert req.http_version == b"1.0"
+
+    # This is also okay -- has a Host (with weird capitalization, which is ok)
+    req = Request(
+        method="GET",
+        target="/",
+        headers=[("a", "b"), ("hOSt", "example.com")],
+        http_version="1.1",
+    )
+    # we normalize header capitalization
+    assert req.headers == [(b"a", b"b"), (b"host", b"example.com")]
+
+    # Multiple host is bad too
+    with pytest.raises(LocalProtocolError):
+        req = Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "a"), ("Host", "a")],
+            http_version="1.1",
+        )
+    # Even for HTTP/1.0
+    with pytest.raises(LocalProtocolError):
+        req = Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "a"), ("Host", "a")],
+            http_version="1.0",
+        )
+
+    # Header values are validated
+    for bad_char in "\x00\r\n\f\v":
+        with pytest.raises(LocalProtocolError):
+            req = Request(
+                method="GET",
+                target="/",
+                headers=[("Host", "a"), ("Foo", "asd" + bad_char)],
+                http_version="1.0",
+            )
+
+    # But for compatibility we allow non-whitespace control characters, even
+    # though they're forbidden by the spec.
+    Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "a"), ("Foo", "asd\x01\x02\x7f")],
+        http_version="1.0",
+    )
+
+    # Request target is validated
+    for bad_byte in b"\x00\x20\x7f\xee":
+        target = bytearray(b"/")
+        target.append(bad_byte)
+        with pytest.raises(LocalProtocolError):
+            Request(
+                method="GET", target=target, headers=[("Host", "a")], http_version="1.1"
+            )
+
+    # Request method is validated
+    with pytest.raises(LocalProtocolError):
+        Request(
+            method="GET / HTTP/1.1",
+            target=target,
+            headers=[("Host", "a")],
+            http_version="1.1",
+        )
+
+    ir = InformationalResponse(status_code=100, headers=[("Host", "a")])
+    assert ir.status_code == 100
+    assert ir.headers == [(b"host", b"a")]
+    assert ir.http_version == b"1.1"
+
+    with pytest.raises(LocalProtocolError):
+        InformationalResponse(status_code=200, headers=[("Host", "a")])
+
+    resp = Response(status_code=204, headers=[], http_version="1.0")  # type: ignore[arg-type]
+    assert resp.status_code == 204
+    assert resp.headers == []
+    assert resp.http_version == b"1.0"
+
+    with pytest.raises(LocalProtocolError):
+        resp = Response(status_code=100, headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    with pytest.raises(LocalProtocolError):
+        Response(status_code="100", headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    with pytest.raises(LocalProtocolError):
+        InformationalResponse(status_code=b"100", headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    d = Data(data=b"asdf")
+    assert d.data == b"asdf"
+
+    eom = EndOfMessage()
+    assert eom.headers == []
+
+    cc = ConnectionClosed()
+    assert repr(cc) == "ConnectionClosed()"
+
+
+def test_intenum_status_code() -> None:
+    # https://github.com/python-hyper/h11/issues/72
+
+    r = Response(status_code=HTTPStatus.OK, headers=[], http_version="1.0")  # type: ignore[arg-type]
+    assert r.status_code == HTTPStatus.OK
+    assert type(r.status_code) is not type(HTTPStatus.OK)
+    assert type(r.status_code) is int
+
+
+def test_header_casing() -> None:
+    r = Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "example.org"), ("Connection", "keep-alive")],
+        http_version="1.1",
+    )
+    assert len(r.headers) == 2
+    assert r.headers[0] == (b"host", b"example.org")
+    assert r.headers == [(b"host", b"example.org"), (b"connection", b"keep-alive")]
+    assert r.headers.raw_items() == [
+        (b"Host", b"example.org"),
+        (b"Connection", b"keep-alive"),
+    ]

venv/lib/python3.11/site-packages/h11/tests/test_headers.py

@@ -0,0 +1,157 @@
+import pytest
+
+from .._events import Request
+from .._headers import (
+    get_comma_header,
+    has_expect_100_continue,
+    Headers,
+    normalize_and_validate,
+    set_comma_header,
+)
+from .._util import LocalProtocolError
+
+
+def test_normalize_and_validate() -> None:
+    assert normalize_and_validate([("foo", "bar")]) == [(b"foo", b"bar")]
+    assert normalize_and_validate([(b"foo", b"bar")]) == [(b"foo", b"bar")]
+
+    # no leading/trailing whitespace in names
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo ", "bar")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b" foo", "bar")])
+
+    # no weird characters in names
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([(b"foo bar", b"baz")])
+    assert "foo bar" in str(excinfo.value)
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\x00bar", b"baz")])
+    # Not even 8-bit characters:
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\xffbar", b"baz")])
+    # And not even the control characters we allow in values:
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\x01bar", b"baz")])
+
+    # no return or NUL characters in values
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([("foo", "bar\rbaz")])
+    assert "bar\\rbaz" in str(excinfo.value)
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "bar\nbaz")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "bar\x00baz")])
+    # no leading/trailing whitespace
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "barbaz  ")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "  barbaz")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "barbaz\t")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "\tbarbaz")])
+
+    # content-length
+    assert normalize_and_validate([("Content-Length", "1")]) == [
+        (b"content-length", b"1")
+    ]
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "asdf")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1x")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1"), ("Content-Length", "2")])
+    assert normalize_and_validate(
+        [("Content-Length", "0"), ("Content-Length", "0")]
+    ) == [(b"content-length", b"0")]
+    assert normalize_and_validate([("Content-Length", "0 , 0")]) == [
+        (b"content-length", b"0")
+    ]
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate(
+            [("Content-Length", "1"), ("Content-Length", "1"), ("Content-Length", "2")]
+        )
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1 , 1,2")])
+
+    # transfer-encoding
+    assert normalize_and_validate([("Transfer-Encoding", "chunked")]) == [
+        (b"transfer-encoding", b"chunked")
+    ]
+    assert normalize_and_validate([("Transfer-Encoding", "cHuNkEd")]) == [
+        (b"transfer-encoding", b"chunked")
+    ]
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([("Transfer-Encoding", "gzip")])
+    assert excinfo.value.error_status_hint == 501  # Not Implemented
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate(
+            [("Transfer-Encoding", "chunked"), ("Transfer-Encoding", "gzip")]
+        )
+    assert excinfo.value.error_status_hint == 501  # Not Implemented
+
+
+def test_get_set_comma_header() -> None:
+    headers = normalize_and_validate(
+        [
+            ("Connection", "close"),
+            ("whatever", "something"),
+            ("connectiON", "fOo,, , BAR"),
+        ]
+    )
+
+    assert get_comma_header(headers, b"connection") == [b"close", b"foo", b"bar"]
+
+    headers = set_comma_header(headers, b"newthing", ["a", "b"])  # type: ignore
+
+    with pytest.raises(LocalProtocolError):
+        set_comma_header(headers, b"newthing", ["  a", "b"])  # type: ignore
+
+    assert headers == [
+        (b"connection", b"close"),
+        (b"whatever", b"something"),
+        (b"connection", b"fOo,, , BAR"),
+        (b"newthing", b"a"),
+        (b"newthing", b"b"),
+    ]
+
+    headers = set_comma_header(headers, b"whatever", ["different thing"])  # type: ignore
+
+    assert headers == [
+        (b"connection", b"close"),
+        (b"connection", b"fOo,, , BAR"),
+        (b"newthing", b"a"),
+        (b"newthing", b"b"),
+        (b"whatever", b"different thing"),
+    ]
+
+
+def test_has_100_continue() -> None:
+    assert has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-continue")],
+        )
+    )
+    assert not has_expect_100_continue(
+        Request(method="GET", target="/", headers=[("Host", "example.com")])
+    )
+    # Case insensitive
+    assert has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-Continue")],
+        )
+    )
+    # Doesn't work in HTTP/1.0
+    assert not has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-continue")],
+            http_version="1.0",
+        )
+    )

venv/lib/python3.11/site-packages/h11/tests/test_helpers.py

@@ -0,0 +1,32 @@
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .helpers import normalize_data_events
+
+
+def test_normalize_data_events() -> None:
+    assert normalize_data_events(
+        [
+            Data(data=bytearray(b"1")),
+            Data(data=b"2"),
+            Response(status_code=200, headers=[]),  # type: ignore[arg-type]
+            Data(data=b"3"),
+            Data(data=b"4"),
+            EndOfMessage(),
+            Data(data=b"5"),
+            Data(data=b"6"),
+            Data(data=b"7"),
+        ]
+    ) == [
+        Data(data=b"12"),
+        Response(status_code=200, headers=[]),  # type: ignore[arg-type]
+        Data(data=b"34"),
+        EndOfMessage(),
+        Data(data=b"567"),
+    ]

venv/lib/python3.11/site-packages/h11/tests/test_io.py

@@ -0,0 +1,572 @@
+from typing import Any, Callable, Generator, List
+
+import pytest
+
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._headers import Headers, normalize_and_validate
+from .._readers import (
+    _obsolete_line_fold,
+    ChunkedReader,
+    ContentLengthReader,
+    Http10Reader,
+    READERS,
+)
+from .._receivebuffer import ReceiveBuffer
+from .._state import (
+    CLIENT,
+    CLOSED,
+    DONE,
+    IDLE,
+    MIGHT_SWITCH_PROTOCOL,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from .._util import LocalProtocolError
+from .._writers import (
+    ChunkedWriter,
+    ContentLengthWriter,
+    Http10Writer,
+    write_any_response,
+    write_headers,
+    write_request,
+    WRITERS,
+)
+from .helpers import normalize_data_events
+
+SIMPLE_CASES = [
+    (
+        (CLIENT, IDLE),
+        Request(
+            method="GET",
+            target="/a",
+            headers=[("Host", "foo"), ("Connection", "close")],
+        ),
+        b"GET /a HTTP/1.1\r\nHost: foo\r\nConnection: close\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        Response(status_code=200, headers=[("Connection", "close")], reason=b"OK"),
+        b"HTTP/1.1 200 OK\r\nConnection: close\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        Response(status_code=200, headers=[], reason=b"OK"),  # type: ignore[arg-type]
+        b"HTTP/1.1 200 OK\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        InformationalResponse(
+            status_code=101, headers=[("Upgrade", "websocket")], reason=b"Upgrade"
+        ),
+        b"HTTP/1.1 101 Upgrade\r\nUpgrade: websocket\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        InformationalResponse(status_code=101, headers=[], reason=b"Upgrade"),  # type: ignore[arg-type]
+        b"HTTP/1.1 101 Upgrade\r\n\r\n",
+    ),
+]
+
+
+def dowrite(writer: Callable[..., None], obj: Any) -> bytes:
+    got_list: List[bytes] = []
+    writer(obj, got_list.append)
+    return b"".join(got_list)
+
+
+def tw(writer: Any, obj: Any, expected: Any) -> None:
+    got = dowrite(writer, obj)
+    assert got == expected
+
+
+def makebuf(data: bytes) -> ReceiveBuffer:
+    buf = ReceiveBuffer()
+    buf += data
+    return buf
+
+
+def tr(reader: Any, data: bytes, expected: Any) -> None:
+    def check(got: Any) -> None:
+        assert got == expected
+        # Headers should always be returned as bytes, not e.g. bytearray
+        # https://github.com/python-hyper/wsproto/pull/54#issuecomment-377709478
+        for name, value in getattr(got, "headers", []):
+            assert type(name) is bytes
+            assert type(value) is bytes
+
+    # Simple: consume whole thing
+    buf = makebuf(data)
+    check(reader(buf))
+    assert not buf
+
+    # Incrementally growing buffer
+    buf = ReceiveBuffer()
+    for i in range(len(data)):
+        assert reader(buf) is None
+        buf += data[i : i + 1]
+    check(reader(buf))
+
+    # Trailing data
+    buf = makebuf(data)
+    buf += b"trailing"
+    check(reader(buf))
+    assert bytes(buf) == b"trailing"
+
+
+def test_writers_simple() -> None:
+    for ((role, state), event, binary) in SIMPLE_CASES:
+        tw(WRITERS[role, state], event, binary)
+
+
+def test_readers_simple() -> None:
+    for ((role, state), event, binary) in SIMPLE_CASES:
+        tr(READERS[role, state], binary, event)
+
+
+def test_writers_unusual() -> None:
+    # Simple test of the write_headers utility routine
+    tw(
+        write_headers,
+        normalize_and_validate([("foo", "bar"), ("baz", "quux")]),
+        b"foo: bar\r\nbaz: quux\r\n\r\n",
+    )
+    tw(write_headers, Headers([]), b"\r\n")
+
+    # We understand HTTP/1.0, but we don't speak it
+    with pytest.raises(LocalProtocolError):
+        tw(
+            write_request,
+            Request(
+                method="GET",
+                target="/",
+                headers=[("Host", "foo"), ("Connection", "close")],
+                http_version="1.0",
+            ),
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tw(
+            write_any_response,
+            Response(
+                status_code=200, headers=[("Connection", "close")], http_version="1.0"
+            ),
+            None,
+        )
+
+
+def test_readers_unusual() -> None:
+    # Reading HTTP/1.0
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.0\r\nSome: header\r\n\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[("Some", "header")],
+            http_version="1.0",
+        ),
+    )
+
+    # check no-headers, since it's only legal with HTTP/1.0
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.0\r\n\r\n",
+        Request(method="HEAD", target="/foo", headers=[], http_version="1.0"),  # type: ignore[arg-type]
+    )
+
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\nSome: header\r\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("Some", "header")],
+            http_version="1.0",
+            reason=b"OK",
+        ),
+    )
+
+    # single-character header values (actually disallowed by the ABNF in RFC
+    # 7230 -- this is a bug in the standard that we originally copied...)
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo: a a a a a \r\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("Foo", "a a a a a")],
+            http_version="1.0",
+            reason=b"OK",
+        ),
+    )
+
+    # Empty headers -- also legal
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo:\r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "")], http_version="1.0", reason=b"OK"
+        ),
+    )
+
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo: \t \t \r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "")], http_version="1.0", reason=b"OK"
+        ),
+    )
+
+    # Tolerate broken servers that leave off the response code
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200\r\n" b"Foo: bar\r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "bar")], http_version="1.0", reason=b""
+        ),
+    )
+
+    # Tolerate headers line endings (\r\n and \n)
+    #    \n\r\b between headers and body
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\r\nSomeHeader: val\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader", "val")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    #   delimited only with \n
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\nSomeHeader1: val1\nSomeHeader2: val2\n\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader1", "val1"), ("SomeHeader2", "val2")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    #   mixed \r\n and \n
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\r\nSomeHeader1: val1\nSomeHeader2: val2\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader1", "val1"), ("SomeHeader2", "val2")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    # obsolete line folding
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.1\r\n"
+        b"Host: example.com\r\n"
+        b"Some: multi-line\r\n"
+        b" header\r\n"
+        b"\tnonsense\r\n"
+        b"    \t   \t\tI guess\r\n"
+        b"Connection: close\r\n"
+        b"More-nonsense: in the\r\n"
+        b"    last header  \r\n\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[
+                ("Host", "example.com"),
+                ("Some", "multi-line header nonsense I guess"),
+                ("Connection", "close"),
+                ("More-nonsense", "in the last header"),
+            ],
+        ),
+    )
+
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"  folded: line\r\n\r\n",
+            None,
+        )
+
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo  : line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo\t: line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo\t: line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(READERS[CLIENT, IDLE], b"HEAD /foo HTTP/1.1\r\n" b": line\r\n\r\n", None)
+
+
+def test__obsolete_line_fold_bytes() -> None:
+    # _obsolete_line_fold has a defensive cast to bytearray, which is
+    # necessary to protect against O(n^2) behavior in case anyone ever passes
+    # in regular bytestrings... but right now we never pass in regular
+    # bytestrings. so this test just exists to get some coverage on that
+    # defensive cast.
+    assert list(_obsolete_line_fold([b"aaa", b"bbb", b"  ccc", b"ddd"])) == [
+        b"aaa",
+        bytearray(b"bbb ccc"),
+        b"ddd",
+    ]
+
+
+def _run_reader_iter(
+    reader: Any, buf: bytes, do_eof: bool
+) -> Generator[Any, None, None]:
+    while True:
+        event = reader(buf)
+        if event is None:
+            break
+        yield event
+        # body readers have undefined behavior after returning EndOfMessage,
+        # because this changes the state so they don't get called again
+        if type(event) is EndOfMessage:
+            break
+    if do_eof:
+        assert not buf
+        yield reader.read_eof()
+
+
+def _run_reader(*args: Any) -> List[Event]:
+    events = list(_run_reader_iter(*args))
+    return normalize_data_events(events)
+
+
+def t_body_reader(thunk: Any, data: bytes, expected: Any, do_eof: bool = False) -> None:
+    # Simple: consume whole thing
+    print("Test 1")
+    buf = makebuf(data)
+    assert _run_reader(thunk(), buf, do_eof) == expected
+
+    # Incrementally growing buffer
+    print("Test 2")
+    reader = thunk()
+    buf = ReceiveBuffer()
+    events = []
+    for i in range(len(data)):
+        events += _run_reader(reader, buf, False)
+        buf += data[i : i + 1]
+    events += _run_reader(reader, buf, do_eof)
+    assert normalize_data_events(events) == expected
+
+    is_complete = any(type(event) is EndOfMessage for event in expected)
+    if is_complete and not do_eof:
+        buf = makebuf(data + b"trailing")
+        assert _run_reader(thunk(), buf, False) == expected
+
+
+def test_ContentLengthReader() -> None:
+    t_body_reader(lambda: ContentLengthReader(0), b"", [EndOfMessage()])
+
+    t_body_reader(
+        lambda: ContentLengthReader(10),
+        b"0123456789",
+        [Data(data=b"0123456789"), EndOfMessage()],
+    )
+
+
+def test_Http10Reader() -> None:
+    t_body_reader(Http10Reader, b"", [EndOfMessage()], do_eof=True)
+    t_body_reader(Http10Reader, b"asdf", [Data(data=b"asdf")], do_eof=False)
+    t_body_reader(
+        Http10Reader, b"asdf", [Data(data=b"asdf"), EndOfMessage()], do_eof=True
+    )
+
+
+def test_ChunkedReader() -> None:
+    t_body_reader(ChunkedReader, b"0\r\n\r\n", [EndOfMessage()])
+
+    t_body_reader(
+        ChunkedReader,
+        b"0\r\nSome: header\r\n\r\n",
+        [EndOfMessage(headers=[("Some", "header")])],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5\r\n01234\r\n"
+        + b"10\r\n0123456789abcdef\r\n"
+        + b"0\r\n"
+        + b"Some: header\r\n\r\n",
+        [
+            Data(data=b"012340123456789abcdef"),
+            EndOfMessage(headers=[("Some", "header")]),
+        ],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5\r\n01234\r\n" + b"10\r\n0123456789abcdef\r\n" + b"0\r\n\r\n",
+        [Data(data=b"012340123456789abcdef"), EndOfMessage()],
+    )
+
+    # handles upper and lowercase hex
+    t_body_reader(
+        ChunkedReader,
+        b"aA\r\n" + b"x" * 0xAA + b"\r\n" + b"0\r\n\r\n",
+        [Data(data=b"x" * 0xAA), EndOfMessage()],
+    )
+
+    # refuses arbitrarily long chunk integers
+    with pytest.raises(LocalProtocolError):
+        # Technically this is legal HTTP/1.1, but we refuse to process chunk
+        # sizes that don't fit into 20 characters of hex
+        t_body_reader(ChunkedReader, b"9" * 100 + b"\r\nxxx", [Data(data=b"xxx")])
+
+    # refuses garbage in the chunk count
+    with pytest.raises(LocalProtocolError):
+        t_body_reader(ChunkedReader, b"10\x00\r\nxxx", None)
+
+    # handles (and discards) "chunk extensions" omg wtf
+    t_body_reader(
+        ChunkedReader,
+        b"5; hello=there\r\n"
+        + b"xxxxx"
+        + b"\r\n"
+        + b'0; random="junk"; some=more; canbe=lonnnnngg\r\n\r\n',
+        [Data(data=b"xxxxx"), EndOfMessage()],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5   	 \r\n01234\r\n" + b"0\r\n\r\n",
+        [Data(data=b"01234"), EndOfMessage()],
+    )
+
+
+def test_ContentLengthWriter() -> None:
+    w = ContentLengthWriter(5)
+    assert dowrite(w, Data(data=b"123")) == b"123"
+    assert dowrite(w, Data(data=b"45")) == b"45"
+    assert dowrite(w, EndOfMessage()) == b""
+
+    w = ContentLengthWriter(5)
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, Data(data=b"123456"))
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123"))
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, Data(data=b"456"))
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123"))
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage())
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123")) == b"123"
+    dowrite(w, Data(data=b"45")) == b"45"
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf")]))
+
+
+def test_ChunkedWriter() -> None:
+    w = ChunkedWriter()
+    assert dowrite(w, Data(data=b"aaa")) == b"3\r\naaa\r\n"
+    assert dowrite(w, Data(data=b"a" * 20)) == b"14\r\n" + b"a" * 20 + b"\r\n"
+
+    assert dowrite(w, Data(data=b"")) == b""
+
+    assert dowrite(w, EndOfMessage()) == b"0\r\n\r\n"
+
+    assert (
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf"), ("a", "b")]))
+        == b"0\r\nEtag: asdf\r\na: b\r\n\r\n"
+    )
+
+
+def test_Http10Writer() -> None:
+    w = Http10Writer()
+    assert dowrite(w, Data(data=b"1234")) == b"1234"
+    assert dowrite(w, EndOfMessage()) == b""
+
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf")]))
+
+
+def test_reject_garbage_after_request_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(READERS[SERVER, SEND_RESPONSE], b"HTTP/1.0 200 OK\x00xxxx\r\n\r\n", None)
+
+
+def test_reject_garbage_after_response_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1 xxxxxx\r\n" b"Host: a\r\n\r\n",
+            None,
+        )
+
+
+def test_reject_garbage_in_header_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"Host: foo\x00bar\r\n\r\n",
+            None,
+        )
+
+
+def test_reject_non_vchar_in_path() -> None:
+    for bad_char in b"\x00\x20\x7f\xee":
+        message = bytearray(b"HEAD /")
+        message.append(bad_char)
+        message.extend(b" HTTP/1.1\r\nHost: foobar\r\n\r\n")
+        with pytest.raises(LocalProtocolError):
+            tr(READERS[CLIENT, IDLE], message, None)
+
+
+# https://github.com/python-hyper/h11/issues/57
+def test_allow_some_garbage_in_cookies() -> None:
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.1\r\n"
+        b"Host: foo\r\n"
+        b"Set-Cookie: ___utmvafIumyLc=kUd\x01UpAt; path=/; Max-Age=900\r\n"
+        b"\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[
+                ("Host", "foo"),
+                ("Set-Cookie", "___utmvafIumyLc=kUd\x01UpAt; path=/; Max-Age=900"),
+            ],
+        ),
+    )
+
+
+def test_host_comes_first() -> None:
+    tw(
+        write_headers,
+        normalize_and_validate([("foo", "bar"), ("Host", "example.com")]),
+        b"Host: example.com\r\nfoo: bar\r\n\r\n",
+    )

venv/lib/python3.11/site-packages/h11/tests/test_receivebuffer.py

@@ -0,0 +1,135 @@
+import re
+from typing import Tuple
+
+import pytest
+
+from .._receivebuffer import ReceiveBuffer
+
+
+def test_receivebuffer() -> None:
+    b = ReceiveBuffer()
+    assert not b
+    assert len(b) == 0
+    assert bytes(b) == b""
+
+    b += b"123"
+    assert b
+    assert len(b) == 3
+    assert bytes(b) == b"123"
+
+    assert bytes(b) == b"123"
+
+    assert b.maybe_extract_at_most(2) == b"12"
+    assert b
+    assert len(b) == 1
+    assert bytes(b) == b"3"
+
+    assert bytes(b) == b"3"
+
+    assert b.maybe_extract_at_most(10) == b"3"
+    assert bytes(b) == b""
+
+    assert b.maybe_extract_at_most(10) is None
+    assert not b
+
+    ################################################################
+    # maybe_extract_until_next
+    ################################################################
+
+    b += b"123\n456\r\n789\r\n"
+
+    assert b.maybe_extract_next_line() == b"123\n456\r\n"
+    assert bytes(b) == b"789\r\n"
+
+    assert b.maybe_extract_next_line() == b"789\r\n"
+    assert bytes(b) == b""
+
+    b += b"12\r"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b"12\r"
+
+    b += b"345\n\r"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b"12\r345\n\r"
+
+    # here we stopped at the middle of b"\r\n" delimiter
+
+    b += b"\n6789aaa123\r\n"
+    assert b.maybe_extract_next_line() == b"12\r345\n\r\n"
+    assert b.maybe_extract_next_line() == b"6789aaa123\r\n"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b""
+
+    ################################################################
+    # maybe_extract_lines
+    ################################################################
+
+    b += b"123\r\na: b\r\nfoo:bar\r\n\r\ntrailing"
+    lines = b.maybe_extract_lines()
+    assert lines == [b"123", b"a: b", b"foo:bar"]
+    assert bytes(b) == b"trailing"
+
+    assert b.maybe_extract_lines() is None
+
+    b += b"\r\n\r"
+    assert b.maybe_extract_lines() is None
+
+    assert b.maybe_extract_at_most(100) == b"trailing\r\n\r"
+    assert not b
+
+    # Empty body case (as happens at the end of chunked encoding if there are
+    # no trailing headers, e.g.)
+    b += b"\r\ntrailing"
+    assert b.maybe_extract_lines() == []
+    assert bytes(b) == b"trailing"
+
+
+@pytest.mark.parametrize(
+    "data",
+    [
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\r\n",
+                b"Content-type: text/plain\r\n",
+                b"Connection: close\r\n",
+                b"\r\n",
+                b"Some body",
+            ),
+            id="with_crlf_delimiter",
+        ),
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\n",
+                b"Content-type: text/plain\n",
+                b"Connection: close\n",
+                b"\n",
+                b"Some body",
+            ),
+            id="with_lf_only_delimiter",
+        ),
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\n",
+                b"Content-type: text/plain\r\n",
+                b"Connection: close\n",
+                b"\n",
+                b"Some body",
+            ),
+            id="with_mixed_crlf_and_lf",
+        ),
+    ],
+)
+def test_receivebuffer_for_invalid_delimiter(data: Tuple[bytes]) -> None:
+    b = ReceiveBuffer()
+
+    for line in data:
+        b += line
+
+    lines = b.maybe_extract_lines()
+
+    assert lines == [
+        b"HTTP/1.1 200 OK",
+        b"Content-type: text/plain",
+        b"Connection: close",
+    ]
+    assert bytes(b) == b"Some body"

venv/lib/python3.11/site-packages/h11/tests/test_state.py

@@ -0,0 +1,271 @@
+import pytest
+
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._state import (
+    _SWITCH_CONNECT,
+    _SWITCH_UPGRADE,
+    CLIENT,
+    CLOSED,
+    ConnectionState,
+    DONE,
+    IDLE,
+    MIGHT_SWITCH_PROTOCOL,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from .._util import LocalProtocolError
+
+
+def test_ConnectionState() -> None:
+    cs = ConnectionState()
+
+    # Basic event-triggered transitions
+
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+    cs.process_event(CLIENT, Request)
+    # The SERVER-Request special case:
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    # Illegal transitions raise an error and nothing happens
+    with pytest.raises(LocalProtocolError):
+        cs.process_event(CLIENT, Request)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, InformationalResponse)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, Response)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_BODY}
+
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, EndOfMessage)
+    assert cs.states == {CLIENT: DONE, SERVER: DONE}
+
+    # State-triggered transition
+
+    cs.process_event(SERVER, ConnectionClosed)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: CLOSED}
+
+
+def test_ConnectionState_keep_alive() -> None:
+    # keep_alive = False
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: MUST_CLOSE}
+
+
+def test_ConnectionState_keep_alive_in_DONE() -> None:
+    # Check that if keep_alive is disabled when the CLIENT is already in DONE,
+    # then this is sufficient to immediately trigger the DONE -> MUST_CLOSE
+    # transition
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states[CLIENT] is DONE
+    cs.process_keep_alive_disabled()
+    assert cs.states[CLIENT] is MUST_CLOSE
+
+
+def test_ConnectionState_switch_denied() -> None:
+    for switch_type in (_SWITCH_CONNECT, _SWITCH_UPGRADE):
+        for deny_early in (True, False):
+            cs = ConnectionState()
+            cs.process_client_switch_proposal(switch_type)
+            cs.process_event(CLIENT, Request)
+            cs.process_event(CLIENT, Data)
+            assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+            assert switch_type in cs.pending_switch_proposals
+
+            if deny_early:
+                # before client reaches DONE
+                cs.process_event(SERVER, Response)
+                assert not cs.pending_switch_proposals
+
+            cs.process_event(CLIENT, EndOfMessage)
+
+            if deny_early:
+                assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+            else:
+                assert cs.states == {
+                    CLIENT: MIGHT_SWITCH_PROTOCOL,
+                    SERVER: SEND_RESPONSE,
+                }
+
+                cs.process_event(SERVER, InformationalResponse)
+                assert cs.states == {
+                    CLIENT: MIGHT_SWITCH_PROTOCOL,
+                    SERVER: SEND_RESPONSE,
+                }
+
+                cs.process_event(SERVER, Response)
+                assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+                assert not cs.pending_switch_proposals
+
+
+_response_type_for_switch = {
+    _SWITCH_UPGRADE: InformationalResponse,
+    _SWITCH_CONNECT: Response,
+    None: Response,
+}
+
+
+def test_ConnectionState_protocol_switch_accepted() -> None:
+    for switch_event in [_SWITCH_UPGRADE, _SWITCH_CONNECT]:
+        cs = ConnectionState()
+        cs.process_client_switch_proposal(switch_event)
+        cs.process_event(CLIENT, Request)
+        cs.process_event(CLIENT, Data)
+        assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+        cs.process_event(CLIENT, EndOfMessage)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+        cs.process_event(SERVER, InformationalResponse)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+        cs.process_event(SERVER, _response_type_for_switch[switch_event], switch_event)
+        assert cs.states == {CLIENT: SWITCHED_PROTOCOL, SERVER: SWITCHED_PROTOCOL}
+
+
+def test_ConnectionState_double_protocol_switch() -> None:
+    # CONNECT + Upgrade is legal! Very silly, but legal. So we support
+    # it. Because sometimes doing the silly thing is easier than not.
+    for server_switch in [None, _SWITCH_UPGRADE, _SWITCH_CONNECT]:
+        cs = ConnectionState()
+        cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+        cs.process_client_switch_proposal(_SWITCH_CONNECT)
+        cs.process_event(CLIENT, Request)
+        cs.process_event(CLIENT, EndOfMessage)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+        cs.process_event(
+            SERVER, _response_type_for_switch[server_switch], server_switch
+        )
+        if server_switch is None:
+            assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+        else:
+            assert cs.states == {CLIENT: SWITCHED_PROTOCOL, SERVER: SWITCHED_PROTOCOL}
+
+
+def test_ConnectionState_inconsistent_protocol_switch() -> None:
+    for client_switches, server_switch in [
+        ([], _SWITCH_CONNECT),
+        ([], _SWITCH_UPGRADE),
+        ([_SWITCH_UPGRADE], _SWITCH_CONNECT),
+        ([_SWITCH_CONNECT], _SWITCH_UPGRADE),
+    ]:
+        cs = ConnectionState()
+        for client_switch in client_switches:  # type: ignore[attr-defined]
+            cs.process_client_switch_proposal(client_switch)
+        cs.process_event(CLIENT, Request)
+        with pytest.raises(LocalProtocolError):
+            cs.process_event(SERVER, Response, server_switch)
+
+
+def test_ConnectionState_keepalive_protocol_switch_interaction() -> None:
+    # keep_alive=False + pending_switch_proposals
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, Data)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    # the protocol switch "wins"
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+    # but when the server denies the request, keep_alive comes back into play
+    cs.process_event(SERVER, Response)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: SEND_BODY}
+
+
+def test_ConnectionState_reuse() -> None:
+    cs = ConnectionState()
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    cs.start_next_cycle()
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+    # No keepalive
+
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # One side closed
+
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(CLIENT, ConnectionClosed)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # Succesful protocol switch
+
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, InformationalResponse, _SWITCH_UPGRADE)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # Failed protocol switch
+
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    cs.start_next_cycle()
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+
+def test_server_request_is_illegal() -> None:
+    # There used to be a bug in how we handled the Request special case that
+    # made this allowed...
+    cs = ConnectionState()
+    with pytest.raises(LocalProtocolError):
+        cs.process_event(SERVER, Request)

venv/lib/python3.11/site-packages/h11/tests/test_util.py

@@ -0,0 +1,112 @@
+import re
+import sys
+import traceback
+from typing import NoReturn
+
+import pytest
+
+from .._util import (
+    bytesify,
+    LocalProtocolError,
+    ProtocolError,
+    RemoteProtocolError,
+    Sentinel,
+    validate,
+)
+
+
+def test_ProtocolError() -> None:
+    with pytest.raises(TypeError):
+        ProtocolError("abstract base class")
+
+
+def test_LocalProtocolError() -> None:
+    try:
+        raise LocalProtocolError("foo")
+    except LocalProtocolError as e:
+        assert str(e) == "foo"
+        assert e.error_status_hint == 400
+
+    try:
+        raise LocalProtocolError("foo", error_status_hint=418)
+    except LocalProtocolError as e:
+        assert str(e) == "foo"
+        assert e.error_status_hint == 418
+
+    def thunk() -> NoReturn:
+        raise LocalProtocolError("a", error_status_hint=420)
+
+    try:
+        try:
+            thunk()
+        except LocalProtocolError as exc1:
+            orig_traceback = "".join(traceback.format_tb(sys.exc_info()[2]))
+            exc1._reraise_as_remote_protocol_error()
+    except RemoteProtocolError as exc2:
+        assert type(exc2) is RemoteProtocolError
+        assert exc2.args == ("a",)
+        assert exc2.error_status_hint == 420
+        new_traceback = "".join(traceback.format_tb(sys.exc_info()[2]))
+        assert new_traceback.endswith(orig_traceback)
+
+
+def test_validate() -> None:
+    my_re = re.compile(rb"(?P<group1>[0-9]+)\.(?P<group2>[0-9]+)")
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.")
+
+    groups = validate(my_re, b"0.1")
+    assert groups == {"group1": b"0", "group2": b"1"}
+
+    # successful partial matches are an error - must match whole string
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.1xx")
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.1\n")
+
+
+def test_validate_formatting() -> None:
+    my_re = re.compile(rb"foo")
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops")
+    assert "oops" in str(excinfo.value)
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops {}")
+    assert "oops {}" in str(excinfo.value)
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops {} xx", 10)
+    assert "oops 10 xx" in str(excinfo.value)
+
+
+def test_make_sentinel() -> None:
+    class S(Sentinel, metaclass=Sentinel):
+        pass
+
+    assert repr(S) == "S"
+    assert S == S
+    assert type(S).__name__ == "S"
+    assert S in {S}
+    assert type(S) is S
+
+    class S2(Sentinel, metaclass=Sentinel):
+        pass
+
+    assert repr(S2) == "S2"
+    assert S != S2
+    assert S not in {S2}
+    assert type(S) is not type(S2)
+
+
+def test_bytesify() -> None:
+    assert bytesify(b"123") == b"123"
+    assert bytesify(bytearray(b"123")) == b"123"
+    assert bytesify("123") == b"123"
+
+    with pytest.raises(UnicodeEncodeError):
+        bytesify("\u1234")
+
+    with pytest.raises(TypeError):
+        bytesify(10)