bvandeusen
8c3d06c0a1
Composes Score over a candidate slice, sorts descending, truncates. Pure — no IO. Liked-rank-higher and high-skip-ranks-last behaviors are stable across RNG seeds (jitter band is smaller than LikeBoost and SkipPenalty).
87 lines
2.6 KiB
Go
87 lines
2.6 KiB
Go
package recommendation
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import (
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"math/rand"
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"testing"
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"time"
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"github.com/jackc/pgx/v5/pgtype"
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"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
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)
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func cand(id string, in ScoringInputs) Candidate {
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t := dbq.Track{Title: id}
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_ = t.ID.Scan("00000000-0000-0000-0000-" + id) // 12-char id padded
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return Candidate{Track: t, Inputs: in}
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}
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func TestShuffle_LikedRanksAboveUnliked(t *testing.T) {
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cs := []Candidate{
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cand("000000000001", ScoringInputs{IsGeneralLiked: false}),
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cand("000000000002", ScoringInputs{IsGeneralLiked: true}),
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}
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out := Shuffle(cs, defaultWeights(), time.Now(), fixedRNG(0.5), 10)
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if out[0].Track.Title != "000000000002" {
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t.Errorf("liked track did not rank first: %+v", out)
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}
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}
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func TestShuffle_HighSkipRanksLast(t *testing.T) {
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cs := []Candidate{
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cand("000000000001", ScoringInputs{PlayCount: 10, SkipCount: 10}), // ratio 1.0
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cand("000000000002", ScoringInputs{PlayCount: 10, SkipCount: 0}), // ratio 0
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cand("000000000003", ScoringInputs{PlayCount: 10, SkipCount: 5}), // ratio 0.5
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}
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out := Shuffle(cs, defaultWeights(), time.Now(), fixedRNG(0.5), 10)
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if out[0].Track.Title != "000000000002" || out[2].Track.Title != "000000000001" {
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t.Errorf("skip-ratio ordering broken: %v", titles(out))
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}
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}
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func TestShuffle_LimitTruncates(t *testing.T) {
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cs := make([]Candidate, 100)
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for i := range cs {
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cs[i] = cand("00000000000"+string(rune('a'+i%26)), ScoringInputs{})
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}
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out := Shuffle(cs, defaultWeights(), time.Now(), fixedRNG(0.5), 10)
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if len(out) != 10 {
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t.Errorf("len = %d, want 10", len(out))
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}
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}
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func TestShuffle_JitterDoesNotFlipStructuralWinner(t *testing.T) {
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// Liked vs unliked: even with many random RNG seeds, liked NEVER ranks below unliked.
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r := rand.New(rand.NewSource(42))
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for i := 0; i < 500; i++ {
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cs := []Candidate{
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cand("000000000001", ScoringInputs{IsGeneralLiked: false}),
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cand("000000000002", ScoringInputs{IsGeneralLiked: true}),
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}
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out := Shuffle(cs, defaultWeights(), time.Now(), r.Float64, 10)
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if out[0].Track.Title != "000000000002" {
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t.Fatalf("iter %d: liked did not rank first; out=%v", i, titles(out))
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}
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}
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}
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func TestShuffle_Empty_ReturnsEmpty(t *testing.T) {
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out := Shuffle(nil, defaultWeights(), time.Now(), fixedRNG(0.5), 10)
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if len(out) != 0 {
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t.Errorf("len = %d, want 0", len(out))
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}
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}
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func titles(cs []Candidate) []string {
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out := make([]string, 0, len(cs))
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for _, c := range cs {
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out = append(out, c.Track.Title)
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}
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return out
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}
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// pgtype-uuid placeholder: Candidate doesn't need a real UUID for these
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// pure tests; the Track.Title field is the human-readable handle. Track ID
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// is left as zero pgtype.UUID and never compared.
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var _ pgtype.UUID
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