diff --git a/changelog.d/11331.misc b/changelog.d/11331.misc
new file mode 100644
index 000000000000..1ab3a6a97591
--- /dev/null
+++ b/changelog.d/11331.misc
@@ -0,0 +1 @@
+A test helper (`wait_for_background_updates`) no longer depends on classes defining a `store` property.
diff --git a/tests/unittest.py b/tests/unittest.py
index eea0903f0574..14318483674e 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -331,16 +331,13 @@ def wait_on_thread(self, deferred, timeout=10):
             time.sleep(0.01)
 
     def wait_for_background_updates(self) -> None:
-        """Block until all background database updates have completed.
-
-        Note that callers must ensure there's a store property created on the
-        testcase.
-        """
+        """Block until all background database updates have completed."""
+        store = self.hs.get_datastore()
         while not self.get_success(
-            self.store.db_pool.updates.has_completed_background_updates()
+            store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db_pool.updates.do_next_background_update(False), by=0.1
+                store.db_pool.updates.do_next_background_update(False), by=0.1
             )
 
     def make_homeserver(self, reactor, clock):