diff --git a/tests/unit/mr_reduction/test_io_orso.py b/tests/unit/mr_reduction/test_io_orso.py
index 90a3e3e..846f2d6 100644
--- a/tests/unit/mr_reduction/test_io_orso.py
+++ b/tests/unit/mr_reduction/test_io_orso.py
@@ -17,7 +17,7 @@
 
 def test_write_orso_output_file_extension():
     with pytest.raises(ValueError, match="Output file must have .ort extension"):
-        write_orso([], "output_file", "cross_section")
+        write_orso([], "output_file")
 
 
 @pytest.mark.datarepo()