diff --git a/tests/api/test_urls.py b/tests/api/test_urls.py
new file mode 100644
index 0000000000..ce156a05dc
--- /dev/null
+++ b/tests/api/test_urls.py
@@ -0,0 +1,55 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2024 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>.
+#
+
+
+from twisted.test.proto_helpers import MemoryReactor
+
+from synapse.api.urls import LoginSSORedirectURIBuilder
+from synapse.server import HomeServer
+from synapse.util import Clock
+
+from tests.unittest import HomeserverTestCase
+
+# a (valid) url with some annoying characters in. %3D is =, %26 is &, %2B is +
+TRICKY_TEST_CLIENT_REDIRECT_URL = 'https://x?<ab c>&q"+%3D%2B"="fö%26=o"'
+
+
+class LoginSSORedirectURIBuilderTestCase(HomeserverTestCase):
+ def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+ self.login_sso_redirect_url_builder = LoginSSORedirectURIBuilder(hs.config)
+
+ def test_no_idp_id(self) -> None:
+ self.assertEqual(
+ self.login_sso_redirect_url_builder.build_login_sso_redirect_uri(
+ idp_id=None, client_redirect_url="http://example.com/redirect"
+ ),
+ "https://test/_matrix/client/v3/login/sso/redirect?redirectUrl=http%3A%2F%2Fexample.com%2Fredirect",
+ )
+
+ def test_explicit_idp_id(self) -> None:
+ self.assertEqual(
+ self.login_sso_redirect_url_builder.build_login_sso_redirect_uri(
+ idp_id="oidc-github", client_redirect_url="http://example.com/redirect"
+ ),
+ "https://test/_matrix/client/v3/login/sso/redirect/oidc-github?redirectUrl=http%3A%2F%2Fexample.com%2Fredirect",
+ )
+
+ def test_tricky_redirect_uri(self) -> None:
+ self.assertEqual(
+ self.login_sso_redirect_url_builder.build_login_sso_redirect_uri(
+ idp_id="oidc-github",
+ client_redirect_url=TRICKY_TEST_CLIENT_REDIRECT_URL,
+ ),
+ "https://test/_matrix/client/v3/login/sso/redirect/oidc-github?redirectUrl=https%3A%2F%2Fx%3F%3Cab+c%3E%26q%22%2B%253D%252B%22%3D%22f%C3%B6%2526%3Do%22",
+ )
|
