diff --git a/pycrostates/io/tests/test_fiff.py b/pycrostates/io/tests/test_fiff.py
index c443a8d7..0f406d91 100644
--- a/pycrostates/io/tests/test_fiff.py
+++ b/pycrostates/io/tests/test_fiff.py
@@ -290,28 +290,28 @@ def test_prepare_kwargs():
     _prepare_kwargs("ModKMeans", kwargs)
 
     # remove one value
-    kwargs = dict(max_iter=ModK._max_iter, tol=ModK._tol, GEV_=ModK._GEV_)
+    kwargs = dict(max_iter=ModK._max_iter, tol=ModK._tol, GEV_=ModK._GEV_, ignore_polarity=False)
     with pytest.raises(ValueError, match="Wrong kwargs provided for"):
         _prepare_kwargs("ModKMeans", kwargs)
 
 
 def test_prepare_kwargs_ModKMeans():
     """Test invalid key/values for ModKMeans."""
-    kwargs = dict(n_init=-101, max_iter=ModK._max_iter, tol=ModK._tol, GEV_=ModK._GEV_)
+    kwargs = dict(n_init=-101, max_iter=ModK._max_iter, tol=ModK._tol, GEV_=ModK._GEV_, ignore_polarity=False)
     with pytest.raises(ValueError, match="initialization must be a positive integer"):
         _prepare_kwargs("ModKMeans", kwargs)
 
-    kwargs = dict(n_init=ModK._n_init, max_iter=-101, tol=ModK._tol, GEV_=ModK._GEV_)
+    kwargs = dict(n_init=ModK._n_init, max_iter=-101, tol=ModK._tol, GEV_=ModK._GEV_, ignore_polarity=False)
     with pytest.raises(ValueError, match="max iteration must be a positive"):
         _prepare_kwargs("ModKMeans", kwargs)
 
     kwargs = dict(
         n_init=ModK._n_init, max_iter=ModK.max_iter, tol=-101, GEV_=ModK._GEV_
     )
-    with pytest.raises(ValueError, match="tolerance must be a positive number"):
+    with pytest.raises(ValueError, match="tolerance must be a positive number", ignore_polarity=False):
         _prepare_kwargs("ModKMeans", kwargs)
 
-    kwargs = dict(n_init=ModK.n_init, max_iter=ModK.max_iter, tol=ModK.tol, GEV_=101)
+    kwargs = dict(n_init=ModK.n_init, max_iter=ModK.max_iter, tol=ModK.tol, GEV_=101, ignore_polarity=False)
     with pytest.raises(
         ValueError, match="'GEV_' should be a percentage between 0 and 1"
     ):