Improve UsernamePickerTestCase (#9112)

* make the OIDC bits of the test work at a higher level - via the REST api instead of poking the OIDCHandler directly.
* Move it to test_login.py, where I think it fits better.

tests/handlers/test_oidc.py

@@ -13,20 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import json
-import re
-from typing import Dict, Optional
-from urllib.parse import parse_qs, urlencode, urlparse
+from typing import Optional
+from urllib.parse import parse_qs, urlparse
 
 from mock import ANY, Mock, patch
 
 import pymacaroons
 
-from twisted.web.resource import Resource
-
-from synapse.api.errors import RedirectException
 from synapse.handlers.sso import MappingException
-from synapse.rest.client.v1 import login
-from synapse.rest.synapse.client.pick_username import pick_username_resource
 from synapse.server import HomeServer
 from synapse.types import UserID
 
@@ -856,116 +850,6 @@ class OidcHandlerTestCase(HomeserverTestCase):
         )
 
 
-class UsernamePickerTestCase(HomeserverTestCase):
-    if not HAS_OIDC:
-        skip = "requires OIDC"
-
-    servlets = [login.register_servlets]
-
-    def default_config(self):
-        config = super().default_config()
-        config["public_baseurl"] = BASE_URL
-        oidc_config = {
-            "enabled": True,
-            "client_id": CLIENT_ID,
-            "client_secret": CLIENT_SECRET,
-            "issuer": ISSUER,
-            "scopes": SCOPES,
-            "user_mapping_provider": {
-                "config": {"display_name_template": "{{ user.displayname }}"}
-            },
-        }
-
-        # Update this config with what's in the default config so that
-        # override_config works as expected.
-        oidc_config.update(config.get("oidc_config", {}))
-        config["oidc_config"] = oidc_config
-
-        # whitelist this client URI so we redirect straight to it rather than
-        # serving a confirmation page
-        config["sso"] = {"client_whitelist": ["https://whitelisted.client"]}
-        return config
-
-    def create_resource_dict(self) -> Dict[str, Resource]:
-        d = super().create_resource_dict()
-        d["/_synapse/client/pick_username"] = pick_username_resource(self.hs)
-        return d
-
-    def test_username_picker(self):
-        """Test the happy path of a username picker flow."""
-        client_redirect_url = "https://whitelisted.client"
-
-        # first of all, mock up an OIDC callback to the OidcHandler, which should
-        # raise a RedirectException
-        userinfo = {"sub": "tester", "displayname": "Jonny"}
-        f = self.get_failure(
-            _make_callback_with_userinfo(
-                self.hs, userinfo, client_redirect_url=client_redirect_url
-            ),
-            RedirectException,
-        )
-
-        # check the Location and cookies returned by the RedirectException
-        self.assertEqual(f.value.location, b"/_synapse/client/pick_username")
-        cookieheader = f.value.cookies[0]
-        regex = re.compile(b"^username_mapping_session=([a-zA-Z]+);")
-        m = regex.search(cookieheader)
-        if not m:
-            self.fail("cookie header %s does not match %s" % (cookieheader, regex))
-
-        # introspect the sso handler a bit to check that the username mapping session
-        # looks ok.
-        session_id = m.group(1).decode("ascii")
-        username_mapping_sessions = self.hs.get_sso_handler()._username_mapping_sessions
-        self.assertIn(
-            session_id, username_mapping_sessions, "session id not found in map"
-        )
-        session = username_mapping_sessions[session_id]
-        self.assertEqual(session.remote_user_id, "tester")
-        self.assertEqual(session.display_name, "Jonny")
-        self.assertEqual(session.client_redirect_url, client_redirect_url)
-
-        # the expiry time should be about 15 minutes away
-        expected_expiry = self.clock.time_msec() + (15 * 60 * 1000)
-        self.assertApproximates(session.expiry_time_ms, expected_expiry, tolerance=1000)
-
-        # Now, submit a username to the username picker, which should serve a redirect
-        # back to the client
-        submit_path = f.value.location + b"/submit"
-        content = urlencode({b"username": b"bobby"}).encode("utf8")
-        chan = self.make_request(
-            "POST",
-            path=submit_path,
-            content=content,
-            content_is_form=True,
-            custom_headers=[
-                ("Cookie", cookieheader),
-                # old versions of twisted don't do form-parsing without a valid
-                # content-length header.
-                ("Content-Length", str(len(content))),
-            ],
-        )
-        self.assertEqual(chan.code, 302, chan.result)
-        location_headers = chan.headers.getRawHeaders("Location")
-        # ensure that the returned location starts with the requested redirect URL
-        self.assertEqual(
-            location_headers[0][: len(client_redirect_url)], client_redirect_url
-        )
-
-        # fish the login token out of the returned redirect uri
-        parts = urlparse(location_headers[0])
-        query = parse_qs(parts.query)
-        login_token = query["loginToken"][0]
-
-        # finally, submit the matrix login token to the login API, which gives us our
-        # matrix access token, mxid, and device id.
-        chan = self.make_request(
-            "POST", "/login", content={"type": "m.login.token", "token": login_token},
-        )
-        self.assertEqual(chan.code, 200, chan.result)
-        self.assertEqual(chan.json_body["user_id"], "@bobby:test")
-
-
 async def _make_callback_with_userinfo(
     hs: HomeServer, userinfo: dict, client_redirect_url: str = "http://client/redirect"
 ) -> None: