| diff --git a/tests/util/test_itertools.py b/tests/util/test_itertools.py
index 522c8061f9..1ef0af8e8f 100644
--- a/tests/util/test_itertools.py
+++ b/tests/util/test_itertools.py
@@ -92,3 +92,15 @@ class SortTopologically(TestCase):
         # Valid orderings are `[1, 3, 2, 4]` or `[1, 2, 3, 4]`, but we should
         # always get the same one.
         self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
+
+    def test_duplicates(self):
+        "Test that a graph with duplicate edges work"
+        graph = {1: [], 2: [1, 1], 3: [2, 2], 4: [3]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
+
+    def test_multiple_paths(self):
+        "Test that a graph with multiple paths between two nodes work"
+        graph = {1: [], 2: [1], 3: [2], 4: [3, 2, 1]}  # type: Dict[int, List[int]]
+
+        self.assertEqual(list(sorted_topologically([4, 3, 2, 1], graph)), [1, 2, 3, 4])
diff --git a/tests/utils.py b/tests/utils.py
 index 977eeaf6ee..68033d7535 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -33,7 +33,6 @@ from synapse.api.room_versions import RoomVersions
 from synapse.config.database import DatabaseConnectionConfig
 from synapse.config.homeserver import HomeServerConfig
 from synapse.config.server import DEFAULT_ROOM_VERSION
-from synapse.http.server import HttpServer
 from synapse.logging.context import current_context, set_current_context
 from synapse.server import HomeServer
 from synapse.storage import DataStore
@@ -158,8 +157,8 @@ def default_config(name, parse=False):
             "local": {"per_second": 10000, "burst_count": 10000},
             "remote": {"per_second": 10000, "burst_count": 10000},
         },
+        "rc_3pid_validation": {"per_second": 10000, "burst_count": 10000},
         "saml2_enabled": False,
-        "public_baseurl": None,
         "default_identity_server": None,
         "key_refresh_interval": 24 * 60 * 60 * 1000,
         "old_signing_keys": {},
@@ -352,7 +351,7 @@ def mock_getRawHeaders(headers=None):
 
 
 # This is a mock /resource/ not an entire server
-class MockHttpResource(HttpServer):
+class MockHttpResource:
     def __init__(self, prefix=""):
         self.callbacks = []  # 3-tuple of method/pattern/function
         self.prefix = prefix
 |