Remove a defer.returnValue call.
diff --git a/tests/test_feedexport.py b/tests/test_feedexport.py
index c7d955bc74e..277555608e6 100644
--- a/tests/test_feedexport.py
+++ b/tests/test_feedexport.py
@@ -2299,7 +2299,7 @@ def run_and_export(self, spider_cls, settings):
                     content[feed["format"]].append(file.read_bytes())
         finally:
             self.tearDown()
-        defer.returnValue(content)
+        return content
 
     @defer.inlineCallbacks
     def assertExportedJsonLines(self, items, rows, settings=None):

Fixes #6204 :shrug: 