def test_no_xsd_wfs_only(self):
        """Test whether the WFS data is available, even if XSD schemas cannot
        be resolved."""
        gwf = GrondwaterFilterSearch(
            objecttype=pydov.types.grondwaterfilter.GrondwaterFilter)

        df = gwf.search(max_features=1)
        assert df.iloc[0].pkey_filter is not None