forgot to add corresponding test

Author: zerothi

src/sisl/geom/_category/tests/test_geom_category_direct.py

@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+from __future__ import annotations
+
+import numpy as np
+import pytest
+
+from sisl import AtomCategory
+
+pytestmark = [pytest.mark.geom, pytest.mark.category, pytest.mark.geom_category]
+
+
+def test_geom_category_direct():
+    # Check that categories can be built indistinctively using the kw builder
+    # or directly calling them.
+    AtomCategory.kw(odd={})
+    AtomCategory.kw(fx=(2, None))