Add MatrixRTC backend/services discovery endpoint (#18967)

Co-authored-by: Andrew Morgan <andrew@amorgan.xyz>

tests/rest/client/test_matrixrtc.py

@@ -0,0 +1,105 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2025 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>.
+#
+# [This file includes modifications made by New Vector Limited]
+#
+#
+
+"""Tests REST events for /rtc/endpoints path."""
+
+from twisted.internet.testing import MemoryReactor
+
+from synapse.rest import admin
+from synapse.rest.client import login, matrixrtc, register, room
+from synapse.server import HomeServer
+from synapse.util.clock import Clock
+
+from tests.unittest import HomeserverTestCase, override_config
+
+PATH_PREFIX = "/_matrix/client/unstable/org.matrix.msc4143"
+RTC_ENDPOINT = {"type": "focusA", "required_field": "theField"}
+LIVEKIT_ENDPOINT = {
+    "type": "livekit",
+    "livekit_service_url": "https://livekit.example.com",
+}
+
+
+class MatrixRtcTestCase(HomeserverTestCase):
+    """Tests /rtc/transports Client-Server REST API."""
+
+    servlets = [
+        admin.register_servlets,
+        room.register_servlets,
+        login.register_servlets,
+        register.register_servlets,
+        matrixrtc.register_servlets,
+    ]
+
+    def prepare(
+        self, reactor: MemoryReactor, clock: Clock, homeserver: HomeServer
+    ) -> None:
+        self.register_user("alice", "password")
+        self._alice_tok = self.login("alice", "password")
+
+    def test_matrixrtc_endpoint_not_enabled(self) -> None:
+        channel = self.make_request(
+            "GET", f"{PATH_PREFIX}/rtc/transports", access_token=self._alice_tok
+        )
+        self.assertEqual(404, channel.code, channel.json_body)
+        self.assertEqual(
+            "M_UNRECOGNIZED", channel.json_body["errcode"], channel.json_body
+        )
+
+    @override_config({"experimental_features": {"msc4143_enabled": True}})
+    def test_matrixrtc_endpoint_requires_authentication(self) -> None:
+        channel = self.make_request("GET", f"{PATH_PREFIX}/rtc/transports")
+        self.assertEqual(401, channel.code, channel.json_body)
+
+    @override_config(
+        {
+            "experimental_features": {"msc4143_enabled": True},
+            "matrix_rtc": {"transports": [RTC_ENDPOINT]},
+        }
+    )
+    def test_matrixrtc_endpoint_contains_expected_transport(self) -> None:
+        channel = self.make_request(
+            "GET", f"{PATH_PREFIX}/rtc/transports", access_token=self._alice_tok
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assert_dict({"rtc_transports": [RTC_ENDPOINT]}, channel.json_body)
+
+    @override_config(
+        {
+            "experimental_features": {"msc4143_enabled": True},
+            "matrix_rtc": {"transports": []},
+        }
+    )
+    def test_matrixrtc_endpoint_no_transports_configured(self) -> None:
+        channel = self.make_request(
+            "GET", f"{PATH_PREFIX}/rtc/transports", access_token=self._alice_tok
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assert_dict({}, channel.json_body)
+
+    @override_config(
+        {
+            "experimental_features": {"msc4143_enabled": True},
+            "matrix_rtc": {"transports": [LIVEKIT_ENDPOINT]},
+        }
+    )
+    def test_matrixrtc_endpoint_livekit_transport(self) -> None:
+        channel = self.make_request(
+            "GET", f"{PATH_PREFIX}/rtc/transports", access_token=self._alice_tok
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assert_dict({"rtc_transports": [LIVEKIT_ENDPOINT]}, channel.json_body)