from app.services.consumable_vision_algorithm import PredictionCandidate
from app.services.video.session_manager import _rank_topk_for_candidates


def test_rank_respects_candidate_order() -> None:
    topk = [
        PredictionCandidate(label="缝线", confidence=0.9),
        PredictionCandidate(label="纱布", confidence=0.5),
    ]
    ordered = ["纱布", "缝线"]
    ranked = _rank_topk_for_candidates(topk, ordered)
    assert [c.label for c in ranked] == ["纱布", "缝线"]


def test_rank_without_candidates_keeps_model_order() -> None:
    topk = [
        PredictionCandidate(label="a", confidence=0.9),
        PredictionCandidate(label="b", confidence=0.5),
    ]
    ranked = _rank_topk_for_candidates(topk, [])
    assert [c.label for c in ranked] == ["a", "b"]