diff --git a/tests/rest/admin/test_admin.py b/tests/rest/admin/test_admin.py
index d3a4f717f7..8e1ca8b738 100644
--- a/tests/rest/admin/test_admin.py
+++ b/tests/rest/admin/test_admin.py
@@ -561,3 +561,81 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         return channel.json_body["groups"]
+
+
+class PurgeRoomTestCase(unittest.HomeserverTestCase):
+    """Test /purge_room admin API.
+    """
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+    def test_purge_room(self):
+        room_id = self.helper.create_room_as(self.admin_user, tok=self.admin_user_tok)
+
+        # All users have to have left the room.
+        self.helper.leave(room_id, user=self.admin_user, tok=self.admin_user_tok)
+
+        url = "/_synapse/admin/v1/purge_room"
+        request, channel = self.make_request(
+            "POST",
+            url.encode("ascii"),
+            {"room_id": room_id},
+            access_token=self.admin_user_tok,
+        )
+        self.render(request)
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # Test that the following tables have been purged of all rows related to the room.
+        for table in (
+            "current_state_events",
+            "event_backward_extremities",
+            "event_forward_extremities",
+            "event_json",
+            "event_push_actions",
+            "event_search",
+            "events",
+            "group_rooms",
+            "public_room_list_stream",
+            "receipts_graph",
+            "receipts_linearized",
+            "room_aliases",
+            "room_depth",
+            "room_memberships",
+            "room_stats_state",
+            "room_stats_current",
+            "room_stats_historical",
+            "room_stats_earliest_token",
+            "rooms",
+            "stream_ordering_to_exterm",
+            "users_in_public_rooms",
+            "users_who_share_private_rooms",
+            "appservice_room_list",
+            "e2e_room_keys",
+            "event_push_summary",
+            "pusher_throttle",
+            "group_summary_rooms",
+            "local_invites",
+            "room_account_data",
+            "room_tags",
+        ):
+            count = self.get_success(
+                self.store._simple_select_one_onecol(
+                    table="events",
+                    keyvalues={"room_id": room_id},
+                    retcol="COUNT(*)",
+                    desc="test_purge_room",
+                )
+            )
+
+            self.assertEqual(count, 0, msg="Rows not purged in {}".format(table))
diff --git a/tests/server.py b/tests/server.py
index e397ebe8fa..469efb4edb 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -161,7 +161,11 @@ def make_request(
         path = path.encode("ascii")
 
     # Decorate it to be the full path, if we're using shorthand
-    if shorthand and not path.startswith(b"/_matrix"):
+    if (
+        shorthand
+        and not path.startswith(b"/_matrix")
+        and not path.startswith(b"/_synapse")
+    ):
         path = b"/_matrix/client/r0/" + path
         path = path.replace(b"//", b"/")