diff --git a/tests/test_rtutil.py b/tests/test_rtutil.py
index 7c285d0..e51c23c 100644
--- a/tests/test_rtutil.py
+++ b/tests/test_rtutil.py
@@ -55,11 +55,15 @@ def new_client():
         TICKET_DATA = testutil.RTClient.TICKET_DATA.copy()
     return RTClient()
 
+@contextlib.contextmanager
+def nullcontext(thing):
+    yield thing
+
 def new_cache(database=':memory:'):
     db = rtutil.RTLinkCache.setup(database)
     if db is None:
         print("NOTE: did not set up database cache at {}".format(database))
-        return contextlib.nullcontext(db)
+        return nullcontext(db)
     else:
         return contextlib.closing(db)