Fix some tests which leaked logcontexts

tests/test_server.py

@@ -27,6 +27,7 @@ from synapse.api.errors import Codes, SynapseError
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite, logger
 from synapse.util import Clock
+from synapse.util.logcontext import make_deferred_yieldable
 
 from tests import unittest
 from tests.server import FakeTransport, make_request, render, setup_test_homeserver
@@ -95,7 +96,7 @@ class JsonResourceTests(unittest.TestCase):
             d = Deferred()
             d.addCallback(_throw)
             self.reactor.callLater(1, d.callback, True)
-            return d
+            return make_deferred_yieldable(d)
 
         res = JsonResource(self.homeserver)
         res.register_paths("GET", [re.compile("^/_matrix/foo$")], _callback)