0
0
Fork 1
mirror of https://mau.dev/maunium/synapse.git synced 2024-05-17 11:03:46 +02:00
synapse/tests/rest/client/utils.py
Richard van der Hoff 05957ac70f
Fix bug in /sync response for archived rooms (#16932)
This PR fixes a very, very niche edge-case, but I've got some more work
coming which will otherwise make the problem worse.

The bug happens when the syncing user leaves a room, and has a sync
filter which includes "left" rooms, but sets the timeline limit to 0. In
that case, the state returned in the `state` section is calculated
incorrectly.

The fix is to pass a token corresponding to the point that the user
leaves the room through to `compute_state_delta`.
2024-04-04 12:47:59 +01:00

942 lines
31 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2019-2021 The Matrix.org Foundation C.I.C.
# Copyright 2017 Vector Creations Ltd
# Copyright 2014-2016 OpenMarket Ltd
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import json
import re
import time
import urllib.parse
from http import HTTPStatus
from typing import (
Any,
AnyStr,
Dict,
Iterable,
Mapping,
MutableMapping,
Optional,
Tuple,
overload,
)
from urllib.parse import urlencode
import attr
from typing_extensions import Literal
from twisted.test.proto_helpers import MemoryReactorClock
from twisted.web.server import Site
from synapse.api.constants import Membership
from synapse.api.errors import Codes
from synapse.server import HomeServer
from synapse.types import JsonDict
from tests.server import FakeChannel, make_request
from tests.test_utils.html_parsers import TestHtmlParser
from tests.test_utils.oidc import FakeAuthorizationGrant, FakeOidcServer
# an 'oidc_config' suitable for login_via_oidc.
TEST_OIDC_ISSUER = "https://issuer.test/"
TEST_OIDC_CONFIG = {
"enabled": True,
"issuer": TEST_OIDC_ISSUER,
"client_id": "test-client-id",
"client_secret": "test-client-secret",
"scopes": ["openid"],
"user_mapping_provider": {"config": {"localpart_template": "{{ user.sub }}"}},
}
@attr.s(auto_attribs=True)
class RestHelper:
"""Contains extra helper functions to quickly and clearly perform a given
REST action, which isn't the focus of the test.
"""
hs: HomeServer
reactor: MemoryReactorClock
site: Site
auth_user_id: Optional[str]
@overload
def create_room_as(
self,
room_creator: Optional[str] = ...,
is_public: Optional[bool] = ...,
room_version: Optional[str] = ...,
tok: Optional[str] = ...,
expect_code: Literal[200] = ...,
extra_content: Optional[Dict] = ...,
custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = ...,
) -> str: ...
@overload
def create_room_as(
self,
room_creator: Optional[str] = ...,
is_public: Optional[bool] = ...,
room_version: Optional[str] = ...,
tok: Optional[str] = ...,
expect_code: int = ...,
extra_content: Optional[Dict] = ...,
custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = ...,
) -> Optional[str]: ...
def create_room_as(
self,
room_creator: Optional[str] = None,
is_public: Optional[bool] = True,
room_version: Optional[str] = None,
tok: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
extra_content: Optional[Dict] = None,
custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = None,
) -> Optional[str]:
"""
Create a room.
Args:
room_creator: The user ID to create the room with.
is_public: If True, the `visibility` parameter will be set to
"public". If False, it will be set to "private".
If None, doesn't specify the `visibility` parameter in which
case the server is supposed to make the room private according to
the CS API.
Defaults to public, since that is commonly needed in tests
for convenience where room privacy is not a problem.
room_version: The room version to create the room as. Defaults to Synapse's
default room version.
tok: The access token to use in the request.
expect_code: The expected HTTP response code.
extra_content: Extra keys to include in the body of the /createRoom request.
Note that if is_public is set, the "visibility" key will be overridden.
If room_version is set, the "room_version" key will be overridden.
custom_headers: HTTP headers to include in the request.
Returns:
The ID of the newly created room, or None if the request failed.
"""
temp_id = self.auth_user_id
self.auth_user_id = room_creator
path = "/_matrix/client/r0/createRoom"
content = extra_content or {}
if is_public is not None:
content["visibility"] = "public" if is_public else "private"
if room_version:
content["room_version"] = room_version
if tok:
path = path + "?access_token=%s" % tok
channel = make_request(
self.reactor,
self.site,
"POST",
path,
content,
custom_headers=custom_headers,
)
assert channel.code == expect_code, channel.result
self.auth_user_id = temp_id
if expect_code == HTTPStatus.OK:
return channel.json_body["room_id"]
else:
return None
def invite(
self,
room: str,
src: Optional[str] = None,
targ: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
tok: Optional[str] = None,
) -> JsonDict:
return self.change_membership(
room=room,
src=src,
targ=targ,
tok=tok,
membership=Membership.INVITE,
expect_code=expect_code,
)
def join(
self,
room: str,
user: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
tok: Optional[str] = None,
appservice_user_id: Optional[str] = None,
expect_errcode: Optional[Codes] = None,
expect_additional_fields: Optional[dict] = None,
) -> JsonDict:
return self.change_membership(
room=room,
src=user,
targ=user,
tok=tok,
appservice_user_id=appservice_user_id,
membership=Membership.JOIN,
expect_code=expect_code,
expect_errcode=expect_errcode,
expect_additional_fields=expect_additional_fields,
)
def knock(
self,
room: Optional[str] = None,
user: Optional[str] = None,
reason: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
tok: Optional[str] = None,
) -> None:
temp_id = self.auth_user_id
self.auth_user_id = user
path = "/knock/%s" % room
if tok:
path = path + "?access_token=%s" % tok
data = {}
if reason:
data["reason"] = reason
channel = make_request(
self.reactor,
self.site,
"POST",
path,
data,
)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
self.auth_user_id = temp_id
def leave(
self,
room: str,
user: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
tok: Optional[str] = None,
) -> JsonDict:
return self.change_membership(
room=room,
src=user,
targ=user,
tok=tok,
membership=Membership.LEAVE,
expect_code=expect_code,
)
def ban(
self,
room: str,
src: str,
targ: str,
expect_code: int = HTTPStatus.OK,
tok: Optional[str] = None,
) -> None:
"""A convenience helper: `change_membership` with `membership` preset to "ban"."""
self.change_membership(
room=room,
src=src,
targ=targ,
tok=tok,
membership=Membership.BAN,
expect_code=expect_code,
)
def change_membership(
self,
room: str,
src: Optional[str],
targ: Optional[str],
membership: str,
extra_data: Optional[dict] = None,
tok: Optional[str] = None,
appservice_user_id: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
expect_errcode: Optional[str] = None,
expect_additional_fields: Optional[dict] = None,
) -> JsonDict:
"""
Send a membership state event into a room.
Args:
room: The ID of the room to send to
src: The mxid of the event sender
targ: The mxid of the event's target. The state key
membership: The type of membership event
extra_data: Extra information to include in the content of the event
tok: The user access token to use
appservice_user_id: The `user_id` URL parameter to pass.
This allows driving an application service user
using an application service access token in `tok`.
expect_code: The expected HTTP response code
expect_errcode: The expected Matrix error code
Returns:
The JSON response
"""
temp_id = self.auth_user_id
self.auth_user_id = src
path = f"/_matrix/client/r0/rooms/{room}/state/m.room.member/{targ}"
url_params: Dict[str, str] = {}
if tok:
url_params["access_token"] = tok
if appservice_user_id:
url_params["user_id"] = appservice_user_id
if url_params:
path += "?" + urlencode(url_params)
data = {"membership": membership}
data.update(extra_data or {})
channel = make_request(
self.reactor,
self.site,
"PUT",
path,
data,
)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
if expect_errcode:
assert (
str(channel.json_body["errcode"]) == expect_errcode
), "Expected: %r, got: %r, resp: %r" % (
expect_errcode,
channel.json_body["errcode"],
channel.result["body"],
)
if expect_additional_fields is not None:
for expect_key, expect_value in expect_additional_fields.items():
assert expect_key in channel.json_body, "Expected field %s, got %s" % (
expect_key,
channel.json_body,
)
assert (
channel.json_body[expect_key] == expect_value
), "Expected: %s at %s, got: %s, resp: %s" % (
expect_value,
expect_key,
channel.json_body[expect_key],
channel.json_body,
)
self.auth_user_id = temp_id
return channel.json_body
def send(
self,
room_id: str,
body: Optional[str] = None,
txn_id: Optional[str] = None,
tok: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = None,
type: str = "m.room.message",
) -> JsonDict:
if body is None:
body = "body_text_here"
content = {"msgtype": "m.text", "body": body}
return self.send_event(
room_id,
type,
content,
txn_id,
tok,
expect_code,
custom_headers=custom_headers,
)
def send_event(
self,
room_id: str,
type: str,
content: Optional[dict] = None,
txn_id: Optional[str] = None,
tok: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = None,
) -> JsonDict:
if txn_id is None:
txn_id = "m%s" % (str(time.time()))
path = "/_matrix/client/r0/rooms/%s/send/%s/%s" % (room_id, type, txn_id)
if tok:
path = path + "?access_token=%s" % tok
channel = make_request(
self.reactor,
self.site,
"PUT",
path,
content or {},
custom_headers=custom_headers,
)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
return channel.json_body
def get_event(
self,
room_id: str,
event_id: str,
tok: Optional[str] = None,
expect_code: int = HTTPStatus.OK,
) -> JsonDict:
"""Request a specific event from the server.
Args:
room_id: the room in which the event was sent.
event_id: the event's ID.
tok: the token to request the event with.
expect_code: the expected HTTP status for the response.
Returns:
The event as a dict.
"""
path = f"/_matrix/client/v3/rooms/{room_id}/event/{event_id}"
if tok:
path = path + f"?access_token={tok}"
channel = make_request(
self.reactor,
self.site,
"GET",
path,
)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
return channel.json_body
def _read_write_state(
self,
room_id: str,
event_type: str,
body: Optional[Dict[str, Any]],
tok: Optional[str],
expect_code: int = HTTPStatus.OK,
state_key: str = "",
method: str = "GET",
) -> JsonDict:
"""Read or write some state from a given room
Args:
room_id:
event_type: The type of state event
body: Body that is sent when making the request. The content of the state event.
If None, the request to the server will have an empty body
tok: The access token to use
expect_code: The HTTP code to expect in the response
state_key:
method: "GET" or "PUT" for reading or writing state, respectively
Returns:
The response body from the server
Raises:
AssertionError: if expect_code doesn't match the HTTP code we received
"""
path = "/_matrix/client/r0/rooms/%s/state/%s/%s" % (
room_id,
event_type,
state_key,
)
if tok:
path = path + "?access_token=%s" % tok
# Set request body if provided
content = b""
if body is not None:
content = json.dumps(body).encode("utf8")
channel = make_request(self.reactor, self.site, method, path, content)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
return channel.json_body
def get_state(
self,
room_id: str,
event_type: str,
tok: str,
expect_code: int = HTTPStatus.OK,
state_key: str = "",
) -> JsonDict:
"""Gets some state from a room
Args:
room_id:
event_type: The type of state event
tok: The access token to use
expect_code: The HTTP code to expect in the response
state_key:
Returns:
The response body from the server
Raises:
AssertionError: if expect_code doesn't match the HTTP code we received
"""
return self._read_write_state(
room_id, event_type, None, tok, expect_code, state_key, method="GET"
)
def send_state(
self,
room_id: str,
event_type: str,
body: Dict[str, Any],
tok: Optional[str],
expect_code: int = HTTPStatus.OK,
state_key: str = "",
) -> JsonDict:
"""Set some state in a room
Args:
room_id:
event_type: The type of state event
body: Body that is sent when making the request. The content of the state event.
tok: The access token to use
expect_code: The HTTP code to expect in the response
state_key:
Returns:
The response body from the server
Raises:
AssertionError: if expect_code doesn't match the HTTP code we received
"""
return self._read_write_state(
room_id, event_type, body, tok, expect_code, state_key, method="PUT"
)
def upload_media(
self,
image_data: bytes,
tok: str,
filename: str = "test.png",
expect_code: int = HTTPStatus.OK,
) -> JsonDict:
"""Upload a piece of test media to the media repo
Args:
resource: The resource that will handle the upload request
image_data: The image data to upload
tok: The user token to use during the upload
filename: The filename of the media to be uploaded
expect_code: The return code to expect from attempting to upload the media
"""
image_length = len(image_data)
path = "/_matrix/media/r0/upload?filename=%s" % (filename,)
channel = make_request(
self.reactor,
self.site,
"POST",
path,
content=image_data,
access_token=tok,
custom_headers=[("Content-Length", str(image_length))],
)
assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
return channel.json_body
def whoami(
self,
access_token: str,
expect_code: Literal[HTTPStatus.OK, HTTPStatus.UNAUTHORIZED] = HTTPStatus.OK,
) -> JsonDict:
"""Perform a 'whoami' request, which can be a quick way to check for access
token validity
Args:
access_token: The user token to use during the request
expect_code: The return code to expect from attempting the whoami request
"""
channel = make_request(
self.reactor,
self.site,
"GET",
"account/whoami",
access_token=access_token,
)
assert channel.code == expect_code, "Exepcted: %d, got %d, resp: %r" % (
expect_code,
channel.code,
channel.result["body"],
)
return channel.json_body
def fake_oidc_server(self, issuer: str = TEST_OIDC_ISSUER) -> FakeOidcServer:
"""Create a ``FakeOidcServer``.
This can be used in conjuction with ``login_via_oidc``::
fake_oidc_server = self.helper.fake_oidc_server()
login_data, _ = self.helper.login_via_oidc(fake_oidc_server, "user")
"""
return FakeOidcServer(
clock=self.hs.get_clock(),
issuer=issuer,
)
def login_via_oidc(
self,
fake_server: FakeOidcServer,
remote_user_id: str,
with_sid: bool = False,
idp_id: Optional[str] = None,
expected_status: int = 200,
) -> Tuple[JsonDict, FakeAuthorizationGrant]:
"""Log in (as a new user) via OIDC
Returns the result of the final token login and the fake authorization grant.
Requires that "oidc_config" in the homeserver config be set appropriately
(TEST_OIDC_CONFIG is a suitable example) - and by implication, needs a
"public_base_url".
Also requires the login servlet and the OIDC callback resource to be mounted at
the normal places.
"""
client_redirect_url = "https://x"
userinfo = {"sub": remote_user_id}
channel, grant = self.auth_via_oidc(
fake_server,
userinfo,
client_redirect_url,
with_sid=with_sid,
idp_id=idp_id,
)
# expect a confirmation page
assert channel.code == HTTPStatus.OK, channel.result
# fish the matrix login token out of the body of the confirmation page
m = re.search(
'a href="%s.*loginToken=([^"]*)"' % (client_redirect_url,),
channel.text_body,
)
assert m, channel.text_body
login_token = m.group(1)
return self.login_via_token(login_token, expected_status), grant
def login_via_token(
self,
login_token: str,
expected_status: int = 200,
) -> JsonDict:
"""Submit the matrix login token to the login API, which gives us our
matrix access token and device id.Log in (as a new user) via OIDC
Returns the result of the token login.
Requires that "oidc_config" in the homeserver config be set appropriately
(TEST_OIDC_CONFIG is a suitable example) - and by implication, needs a
"public_base_url".
Also requires the login servlet and the OIDC callback resource to be mounted at
the normal places.
"""
channel = make_request(
self.reactor,
self.site,
"POST",
"/login",
content={"type": "m.login.token", "token": login_token},
)
assert (
channel.code == expected_status
), f"unexpected status in response: {channel.code}"
return channel.json_body
def auth_via_oidc(
self,
fake_server: FakeOidcServer,
user_info_dict: JsonDict,
client_redirect_url: Optional[str] = None,
ui_auth_session_id: Optional[str] = None,
with_sid: bool = False,
idp_id: Optional[str] = None,
) -> Tuple[FakeChannel, FakeAuthorizationGrant]:
"""Perform an OIDC authentication flow via a mock OIDC provider.
This can be used for either login or user-interactive auth.
Starts by making a request to the relevant synapse redirect endpoint, which is
expected to serve a 302 to the OIDC provider. We then make a request to the
OIDC callback endpoint, intercepting the HTTP requests that will get sent back
to the OIDC provider.
Requires that "oidc_config" in the homeserver config be set appropriately
(TEST_OIDC_CONFIG is a suitable example) - and by implication, needs a
"public_base_url".
Also requires the login servlet and the OIDC callback resource to be mounted at
the normal places.
Args:
user_info_dict: the remote userinfo that the OIDC provider should present.
Typically this should be '{"sub": "<remote user id>"}'.
client_redirect_url: for a login flow, the client redirect URL to pass to
the login redirect endpoint
ui_auth_session_id: if set, we will perform a UI Auth flow. The session id
of the UI auth.
with_sid: if True, generates a random `sid` (OIDC session ID)
idp_id: if set, explicitely chooses one specific IDP
Returns:
A FakeChannel containing the result of calling the OIDC callback endpoint.
Note that the response code may be a 200, 302 or 400 depending on how things
went.
"""
cookies: Dict[str, str] = {}
with fake_server.patch_homeserver(hs=self.hs):
# if we're doing a ui auth, hit the ui auth redirect endpoint
if ui_auth_session_id:
# can't set the client redirect url for UI Auth
assert client_redirect_url is None
oauth_uri = self.initiate_sso_ui_auth(ui_auth_session_id, cookies)
else:
# otherwise, hit the login redirect endpoint
oauth_uri = self.initiate_sso_login(
client_redirect_url, cookies, idp_id=idp_id
)
# we now have a URI for the OIDC IdP, but we skip that and go straight
# back to synapse's OIDC callback resource. However, we do need the "state"
# param that synapse passes to the IdP via query params, as well as the cookie
# that synapse passes to the client.
oauth_uri_path, _ = oauth_uri.split("?", 1)
assert oauth_uri_path == fake_server.authorization_endpoint, (
"unexpected SSO URI " + oauth_uri_path
)
return self.complete_oidc_auth(
fake_server, oauth_uri, cookies, user_info_dict, with_sid=with_sid
)
def complete_oidc_auth(
self,
fake_serer: FakeOidcServer,
oauth_uri: str,
cookies: Mapping[str, str],
user_info_dict: JsonDict,
with_sid: bool = False,
) -> Tuple[FakeChannel, FakeAuthorizationGrant]:
"""Mock out an OIDC authentication flow
Assumes that an OIDC auth has been initiated by one of initiate_sso_login or
initiate_sso_ui_auth; completes the OIDC bits of the flow by making a request to
Synapse's OIDC callback endpoint, intercepting the HTTP requests that will get
sent back to the OIDC provider.
Requires the OIDC callback resource to be mounted at the normal place.
Args:
fake_server: the fake OIDC server with which the auth should be done
oauth_uri: the OIDC URI returned by synapse's redirect endpoint (ie,
from initiate_sso_login or initiate_sso_ui_auth).
cookies: the cookies set by synapse's redirect endpoint, which will be
sent back to the callback endpoint.
user_info_dict: the remote userinfo that the OIDC provider should present.
Typically this should be '{"sub": "<remote user id>"}'.
with_sid: if True, generates a random `sid` (OIDC session ID)
Returns:
A FakeChannel containing the result of calling the OIDC callback endpoint.
"""
_, oauth_uri_qs = oauth_uri.split("?", 1)
params = urllib.parse.parse_qs(oauth_uri_qs)
code, grant = fake_serer.start_authorization(
scope=params["scope"][0],
userinfo=user_info_dict,
client_id=params["client_id"][0],
redirect_uri=params["redirect_uri"][0],
nonce=params["nonce"][0],
with_sid=with_sid,
)
state = params["state"][0]
callback_uri = "%s?%s" % (
urllib.parse.urlparse(params["redirect_uri"][0]).path,
urllib.parse.urlencode({"state": state, "code": code}),
)
with fake_serer.patch_homeserver(hs=self.hs):
# now hit the callback URI with the right params and a made-up code
channel = make_request(
self.reactor,
self.site,
"GET",
callback_uri,
custom_headers=[
("Cookie", "%s=%s" % (k, v)) for (k, v) in cookies.items()
],
)
return channel, grant
def initiate_sso_login(
self,
client_redirect_url: Optional[str],
cookies: MutableMapping[str, str],
idp_id: Optional[str] = None,
) -> str:
"""Make a request to the login-via-sso redirect endpoint, and return the target
Assumes that exactly one SSO provider has been configured. Requires the login
servlet to be mounted.
Args:
client_redirect_url: the client redirect URL to pass to the login redirect
endpoint
cookies: any cookies returned will be added to this dict
idp_id: if set, explicitely chooses one specific IDP
Returns:
the URI that the client gets redirected to (ie, the SSO server)
"""
params = {}
if client_redirect_url:
params["redirectUrl"] = client_redirect_url
uri = "/_matrix/client/r0/login/sso/redirect"
if idp_id is not None:
uri = f"{uri}/{idp_id}"
uri = f"{uri}?{urllib.parse.urlencode(params)}"
# hit the redirect url (which should redirect back to the redirect url. This
# is the easiest way of figuring out what the Host header ought to be set to
# to keep Synapse happy.
channel = make_request(
self.reactor,
self.site,
"GET",
uri,
)
assert channel.code == 302
# hit the redirect url again with the right Host header, which should now issue
# a cookie and redirect to the SSO provider.
def get_location(channel: FakeChannel) -> str:
location_values = channel.headers.getRawHeaders("Location")
# Keep mypy happy by asserting that location_values is nonempty
assert location_values
return location_values[0]
location = get_location(channel)
parts = urllib.parse.urlsplit(location)
channel = make_request(
self.reactor,
self.site,
"GET",
urllib.parse.urlunsplit(("", "") + parts[2:]),
custom_headers=[
("Host", parts[1]),
],
)
assert channel.code == 302
channel.extract_cookies(cookies)
return get_location(channel)
def initiate_sso_ui_auth(
self, ui_auth_session_id: str, cookies: MutableMapping[str, str]
) -> str:
"""Make a request to the ui-auth-via-sso endpoint, and return the target
Assumes that exactly one SSO provider has been configured. Requires the
AuthRestServlet to be mounted.
Args:
ui_auth_session_id: the session id of the UI auth
cookies: any cookies returned will be added to this dict
Returns:
the URI that the client gets linked to (ie, the SSO server)
"""
sso_redirect_endpoint = (
"/_matrix/client/r0/auth/m.login.sso/fallback/web?"
+ urllib.parse.urlencode({"session": ui_auth_session_id})
)
# hit the redirect url (which will issue a cookie and state)
channel = make_request(self.reactor, self.site, "GET", sso_redirect_endpoint)
# that should serve a confirmation page
assert channel.code == HTTPStatus.OK, channel.text_body
channel.extract_cookies(cookies)
# parse the confirmation page to fish out the link.
p = TestHtmlParser()
p.feed(channel.text_body)
p.close()
assert len(p.links) == 1, "not exactly one link in confirmation page"
oauth_uri = p.links[0]
return oauth_uri