diff --git a/tests/test_util_inspect.py b/tests/test_util_inspect.py
index cc67e37b3d4..a14c8a15fcd 100644
--- a/tests/test_util_inspect.py
+++ b/tests/test_util_inspect.py
@@ -670,6 +670,7 @@ def __get__(self, obj, typ=None):
         pass
 
 
+@pytest.mark.sphinx(testroot='ext-autodoc')
 def test_isproperty(app):
     from target.functions import func
     from target.methods import Base