Add test case for #5574

There's no test that makes sure #5574 didn't break things or works correctly (my bad), so this PR adds a test case that makes sure of it.

tests/handlers/test_identity.py

@@ -0,0 +1,108 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector Ltd
+#
+# 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 mock import Mock
+
+from twisted.internet import defer
+
+import synapse.rest.admin
+from synapse.rest.client.v1 import login
+from synapse.rest.client.v2_alpha import account
+
+from tests import unittest
+
+
+class ThreepidISRewrittenURLTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+        account.register_servlets,
+    ]
+
+    def make_homeserver(self, reactor, clock):
+        self.address = "test@test"
+        self.is_server_name = "testis"
+        self.rewritten_is_url = "int.testis"
+
+        config = self.default_config()
+        config["trusted_third_party_id_servers"] = [
+            self.is_server_name,
+        ]
+        config["rewrite_identity_server_urls"] = {
+            self.is_server_name: self.rewritten_is_url,
+        }
+
+        mock_http_client = Mock(spec=[
+            "post_urlencoded_get_json",
+        ])
+        mock_http_client.post_urlencoded_get_json.return_value = defer.succeed({
+            "address": self.address,
+            "medium": "email",
+        })
+
+        self.hs = self.setup_test_homeserver(
+            config=config,
+            simple_http_client=mock_http_client,
+        )
+
+        return self.hs
+
+    def prepare(self, reactor, clock, hs):
+        self.user_id = self.register_user("kermit", "monkey")
+
+    def test_rewritten_id_server(self):
+        """
+        Tests that, when validating a 3PID association while rewriting the IS's server
+        name:
+        * the bind request is done against the rewritten hostname
+        * the original, non-rewritten, server name is stored in the database
+        """
+        handler = self.hs.get_handlers().identity_handler
+        post_urlenc_get_json = self.hs.get_simple_http_client().post_urlencoded_get_json
+        store = self.hs.get_datastore()
+
+        creds = {
+            "sid": "123",
+            "client_secret": "some_secret",
+        }
+
+        # Make sure processing the mocked response goes through.
+        data = self.get_success(handler.bind_threepid(
+            {
+                "id_server": self.is_server_name,
+                "client_secret": creds["client_secret"],
+                "sid": creds["sid"],
+            },
+            self.user_id,
+        ))
+        self.assertEqual(data.get("address"), self.address)
+
+        # Check that the request was done against the rewritten server name.
+        post_urlenc_get_json.assert_called_once_with(
+            "https://%s/_matrix/identity/api/v1/3pid/bind" % self.rewritten_is_url,
+            {
+                'sid': creds['sid'],
+                'client_secret': creds["client_secret"],
+                'mxid': self.user_id,
+            }
+        )
+
+        # Check that the original server name is saved in the database instead of the
+        # rewritten one.
+        id_servers = self.get_success(store.get_id_servers_user_bound(
+            self.user_id, "email", self.address
+        ))
+        self.assertEqual(id_servers, [self.is_server_name])