Fix third-party event modules for check_visibility_can_be_modified check

PR #8292 tried to maintain backwards compat with modules which don't provide a
`check_visibility_can_be_modified` method, but the tests weren't being run,
and the check didn't work.

tests/rest/client/test_third_party_rules.py

@@ -0,0 +1,86 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+from synapse.types import Requester
+
+from tests import unittest
+
+
+class ThirdPartyRulesTestModule:
+    def __init__(self, config, *args, **kwargs):
+        pass
+
+    async def on_create_room(
+        self, requester: Requester, config: dict, is_requester_admin: bool
+    ):
+        return True
+
+    async def check_event_allowed(self, event, context):
+        if event.type == "foo.bar.forbidden":
+            return False
+        else:
+            return True
+
+    @staticmethod
+    def parse_config(config):
+        return config
+
+
+class ThirdPartyRulesTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def make_homeserver(self, reactor, clock):
+        config = self.default_config()
+        config["third_party_event_rules"] = {
+            "module": __name__ + ".ThirdPartyRulesTestModule",
+            "config": {},
+        }
+
+        self.hs = self.setup_test_homeserver(config=config)
+        return self.hs
+
+    def prepare(self, reactor, clock, homeserver):
+        # Create a user and room to play with during the tests
+        self.user_id = self.register_user("kermit", "monkey")
+        self.tok = self.login("kermit", "monkey")
+
+        self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
+
+    def test_third_party_rules(self):
+        """Tests that a forbidden event is forbidden from being sent, but an allowed one
+        can be sent.
+        """
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/foo.bar.allowed/1" % self.room_id,
+            {},
+            access_token=self.tok,
+        )
+        self.render(request)
+        self.assertEquals(channel.result["code"], b"200", channel.result)
+
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/foo.bar.forbidden/1" % self.room_id,
+            {},
+            access_token=self.tok,
+        )
+        self.render(request)
+        self.assertEquals(channel.result["code"], b"403", channel.result)