Allow ThirdPartyEventRules modules to manipulate public room state (#8292)

This PR allows `ThirdPartyEventRules` modules to view, manipulate and block changes to the state of whether a room is published in the public rooms directory.

While the idea of whether a room is in the public rooms list is not kept within an event in the room, `ThirdPartyEventRules` generally deal with controlling which modifications can happen to a room. Public rooms fits within that idea, even if its toggle state isn't controlled through a state event.

tests/module_api/test_api.py

@@ -12,13 +12,20 @@
 # 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.module_api import ModuleApi
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
 
 from tests.unittest import HomeserverTestCase
 
 
 class ModuleApiTestCase(HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
     def prepare(self, reactor, clock, homeserver):
         self.store = homeserver.get_datastore()
         self.module_api = ModuleApi(homeserver, homeserver.get_auth_handler())
@@ -52,3 +59,50 @@ class ModuleApiTestCase(HomeserverTestCase):
         # Check that the displayname was assigned
         displayname = self.get_success(self.store.get_profile_displayname("bob"))
         self.assertEqual(displayname, "Bobberino")
+
+    def test_public_rooms(self):
+        """Tests that a room can be added and removed from the public rooms list,
+        as well as have its public rooms directory state queried.
+        """
+        # Create a user and room to play with
+        user_id = self.register_user("kermit", "monkey")
+        tok = self.login("kermit", "monkey")
+        room_id = self.helper.create_room_as(user_id, tok=tok)
+
+        # The room should not currently be in the public rooms directory
+        is_in_public_rooms = self.get_success(
+            self.module_api.public_room_list_manager.room_is_in_public_room_list(
+                room_id
+            )
+        )
+        self.assertFalse(is_in_public_rooms)
+
+        # Let's try adding it to the public rooms directory
+        self.get_success(
+            self.module_api.public_room_list_manager.add_room_to_public_room_list(
+                room_id
+            )
+        )
+
+        # And checking whether it's in there...
+        is_in_public_rooms = self.get_success(
+            self.module_api.public_room_list_manager.room_is_in_public_room_list(
+                room_id
+            )
+        )
+        self.assertTrue(is_in_public_rooms)
+
+        # Let's remove it again
+        self.get_success(
+            self.module_api.public_room_list_manager.remove_room_from_public_room_list(
+                room_id
+            )
+        )
+
+        # Should be gone
+        is_in_public_rooms = self.get_success(
+            self.module_api.public_room_list_manager.room_is_in_public_room_list(
+                room_id
+            )
+        )
+        self.assertFalse(is_in_public_rooms)