def test_get_categorical_features_helper(self, model_cls):
        """Test helper function responsible for retrieving indices of categorical features"""

        model = model_cls(
            lags=1,
            lags_past_covariates=1,
            lags_future_covariates=[1],
            output_chunk_length=1,
            categorical_future_covariates=["fut_cov_promo_mechanism"],
            categorical_past_covariates=["past_cov_cat_dummy"],
            categorical_static_covariates=["product_id"],
        )
        (
            series,
            past_covariates,
            future_covariates,
        ) = self.inputs_for_tests_categorical_covariates()
        (
            indices,
            column_names,
        ) = model._get_categorical_features(
            series=series,
            past_covariates=past_covariates,
            future_covariates=future_covariates,
        )
        assert indices == [2, 3, 5]
        assert column_names == [
            "past_cov_past_cov_cat_dummy_lag-1",
            "fut_cov_fut_cov_promo_mechanism_lag1",
            "static_cov_product_id_lag0",
        ]
Test helper function responsible for retrieving indices of categorical features
darts/tests/models/forecasting/test_sklearn_models.py