diff --git a/pytest.ini b/pytest.ini
index 72ca674..01efc49 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,8 +1,7 @@
 [pytest]
-addopts = --ignore=setup.py
+addopts = --ignore=setup.py --ignore=process_bigraph/experiments/comets.py
 python_files = *.py
 #skip comets tests
-addopts = --ignore=process_bigraph/experiments/comets.py
 testpaths = process_bigraph
 markers =
     slow: indicates slow tests (deselect with '-m "not slow"')