def test_payload_compaction_preserves_candidate_codes_and_measures_reduction():
    from central.app.ai.payloads import compact_payload, measure_payloads

    payload = {"description": "agua", "debug": "remove", "official_candidates": [{"ncm": "22011000", "text": "x"}, {"ncm": "22011000", "text": "x"}, {"ncm": "22019000", "text": "y"}]}
    compact = compact_payload(payload)
    assert [row["ncm"] for row in compact["official_candidates"]] == ["22011000", "22019000"]
    assert "debug" not in compact
    assert measure_payloads([payload])["tokens_after"] < measure_payloads([payload])["tokens_before"]