assertTrue(queryFieldConfig.isFacetSortValue("count"));
        assertTrue(queryFieldConfig.isFacetSortValue("index"));

        // Test invalid facet sort values
        assertFalse(queryFieldConfig.isFacetSortValue("invalid"));
        assertFalse(queryFieldConfig.isFacetSortValue(""));
        assertFalse(queryFieldConfig.isFacetSortValue(null));

     *
     * @param sort the sort value to check
     * @return true if the sort value is valid for facets ("count" or "index"), false otherwise
     */
    public boolean isFacetSortValue(final String sort) {
        return "count".equals(sort) || "index".equals(sort);
    }

    /**
     * Sets the fields that are allowed in API responses.
     *