diff --git a/tests/conftest.py b/tests/conftest.py
index 4bbc8c0..55eb347 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -19,7 +19,7 @@ empty_mark = Mark('', (), {})
 
 
 def by_slow_marker(item):
-    return item.get_closest_marker('slow', default=empty_mark)
+    return item.get_closest_marker('slow', default=empty_mark).name
 
 
 def pytest_collection_modifyitems(items):