use alpha_id::vector::VectorIndex;

#[test]
fn cosine_topk_ranks_nearest_first() {
    let vi = VectorIndex::from_vectors(vec![
        vec![1.0, 0.0],   // id 0
        vec![0.0, 1.0],   // id 1
        vec![0.9, 0.1],   // id 2
    ]);
    let hits = vi.top_k(&[1.0, 0.0], 2);
    assert_eq!(hits[0].0, 0);
    assert_eq!(hits[1].0, 2);
    assert!(hits[0].1 > hits[1].1);
}

#[test]
fn nan_score_does_not_panic_and_dim_mismatch_returns_empty() {
    // NaN in a stored vector must not panic the sort.
    let vi = VectorIndex::from_vectors(vec![vec![1.0, 0.0], vec![f32::NAN, 1.0]]);
    let hits = vi.top_k(&[1.0, 0.0], 2);          // must not panic
    assert!(hits.iter().any(|&(i, _)| i == 0));   // the valid vector still found
    // Dimension mismatch → empty, never silently mispaired.
    let vi2 = VectorIndex::from_vectors(vec![vec![1.0, 0.0, 0.0]]);
    assert!(vi2.top_k(&[1.0, 0.0], 1).is_empty());
}