Files
minstrel/internal/playlists/seed_selection_test.go
T
bvandeusen a670840114
test-go / test (push) Successful in 29s
test-go / integration (push) Successful in 4m30s
fix(playlists): Songs-like mixes no longer vanish after a quiet week
PickSeedArtists had a hard 7-day window with no fallback: a week
without listening emptied the seed pool, produceSeedMixes returned
zero playlists, and the daily atomic-replace build deleted every
existing "Songs like X" mix until the user played something again
(#1255).

The query now falls back through widening engagement windows — 7d →
30d → all-time → liked artists — the same tiered shape that fixed the
identical vanish for For You's seeds (PickTopPlayedTracksForUser).
Like-boost scoring is preserved in every tier.

All returned rows share the winning tier, and produceSeedMixes maps it
onto the rule-#131 pick-kind ladder (7d = tier1 exact, 30d = tier2,
all-time/liked = tier3) and stamps the built tracks — the #1270
provenance pipeline then attributes plays and skips to seed freshness,
so the metrics card can say whether stale-seeded mixes actually
perform worse.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TsF3cNoKrqCYsU78cXC8U6
2026-07-03 08:38:54 -04:00

256 lines
8.0 KiB
Go

package playlists
import (
"testing"
"github.com/jackc/pgx/v5/pgtype"
)
// pickSeedArtistsFromRows is the pure helper that turns sqlc rows into
// the seed list. The DB-level query is exercised in system_test.go's
// integration test; this unit test pins the post-fetch logic.
func TestPickSeedArtistsFromRows_PreservesOrder(t *testing.T) {
mk := func(b byte, score int64) seedArtistRow {
return seedArtistRow{
ArtistID: pgtype.UUID{Bytes: [16]byte{b}, Valid: true},
Score: score,
}
}
// Caller (SQL) already orders + limits; helper preserves order.
rows := []seedArtistRow{mk(1, 100), mk(2, 50), mk(3, 25)}
got := pickSeedArtistsFromRows(rows)
if len(got) != 3 {
t.Fatalf("len: got %d, want 3", len(got))
}
if got[0].Bytes[0] != 1 || got[1].Bytes[0] != 2 || got[2].Bytes[0] != 3 {
t.Errorf("expected [1,2,3] preserving input order; got %v", got)
}
}
func TestPickSeedArtistsFromRows_FewerThanThree(t *testing.T) {
mk := func(b byte, score int64) seedArtistRow {
return seedArtistRow{ArtistID: pgtype.UUID{Bytes: [16]byte{b}, Valid: true}, Score: score}
}
rows := []seedArtistRow{mk(1, 100)}
got := pickSeedArtistsFromRows(rows)
if len(got) != 1 {
t.Errorf("len: got %d, want 1", len(got))
}
}
func TestPickSeedArtistsFromRows_Empty(t *testing.T) {
got := pickSeedArtistsFromRows(nil)
if len(got) != 0 {
t.Errorf("empty input should yield empty output; got %v", got)
}
}
func TestPickKindForSeedTier(t *testing.T) {
// The seed query's fallback tiers map onto the rule-#131 ladder:
// fresh 7-day engagement is the exact desire, everything past the
// 30-day step-back collapses into the far tier (#1255).
cases := []struct {
tier int32
want string
}{
{0, pickKindTier1},
{1, pickKindTier2},
{2, pickKindTier3},
{3, pickKindTier3},
}
for _, c := range cases {
if got := pickKindForSeedTier(c.tier); got != c.want {
t.Errorf("pickKindForSeedTier(%d) = %q, want %q", c.tier, got, c.want)
}
}
}
// userIDHash is the per-user, per-day hash that drives the daily-
// determinism RNGs. Same family as tieBreakHash, just keyed on user
// ID instead of track ID.
func TestUserIDHash_Deterministic(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
a := userIDHash(u, "2026-05-04")
b := userIDHash(u, "2026-05-04")
if a != b {
t.Fatalf("same inputs gave different hashes: %d vs %d", a, b)
}
}
func TestUserIDHash_DifferentDateChangesHash(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
a := userIDHash(u, "2026-05-04")
b := userIDHash(u, "2026-05-05")
if a == b {
t.Errorf("different dates should change hash; both = %d", a)
}
}
func TestUserIDHash_DifferentUserChangesHash(t *testing.T) {
a := pgtype.UUID{Bytes: [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}, Valid: true}
b := pgtype.UUID{Bytes: [16]byte{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1}, Valid: true}
if userIDHash(a, "2026-05-04") == userIDHash(b, "2026-05-04") {
t.Errorf("different users should change hash")
}
}
// pickForYouSeedForDay rotates the chosen For-You seed across the
// user's top-played candidates using userIDHash. Verifies the picker
// is deterministic within a day, varies across days, and degrades
// gracefully when fewer than 5 candidates exist.
func TestPickForYouSeedForDay_DeterministicWithinDay(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
seeds := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
{Bytes: [16]byte{30}, Valid: true},
{Bytes: [16]byte{40}, Valid: true},
{Bytes: [16]byte{50}, Valid: true},
}
a := pickForYouSeedForDay(seeds, u, "2026-05-04")
b := pickForYouSeedForDay(seeds, u, "2026-05-04")
if a != b {
t.Fatalf("same day should pick same seed; got %v then %v", a, b)
}
}
func TestPickForYouSeedForDay_VariesAcrossDays(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
seeds := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
{Bytes: [16]byte{30}, Valid: true},
{Bytes: [16]byte{40}, Valid: true},
{Bytes: [16]byte{50}, Valid: true},
}
picks := map[[16]byte]bool{}
for i := 1; i <= 30; i++ {
date := "2026-05-" + twoDigits(i)
picks[pickForYouSeedForDay(seeds, u, date).Bytes] = true
}
if len(picks) < 2 {
t.Errorf("expected >=2 distinct seeds across 30 days; got %d", len(picks))
}
}
func TestPickForYouSeedForDay_SingleCandidate(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
only := pgtype.UUID{Bytes: [16]byte{99}, Valid: true}
got := pickForYouSeedForDay([]pgtype.UUID{only}, u, "2026-05-04")
if got != only {
t.Errorf("single-seed pool should return that seed; got %v", got)
}
}
func TestPickForYouSeedForDay_EmptyPool(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
got := pickForYouSeedForDay(nil, u, "2026-05-04")
if got.Valid {
t.Errorf("empty pool should return zero UUID; got %v", got)
}
}
// pickSeedArtistsForDay takes the user's top-5 candidate artists and
// returns 3 of them via daily-deterministic shuffle. Verifies the
// picker is deterministic within a day, varies across days, and
// degrades gracefully when fewer than 3 or 5 candidates exist.
func TestPickSeedArtistsForDay_DeterministicWithinDay(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
pool := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
{Bytes: [16]byte{30}, Valid: true},
{Bytes: [16]byte{40}, Valid: true},
{Bytes: [16]byte{50}, Valid: true},
}
a := pickSeedArtistsForDay(pool, u, "2026-05-04")
b := pickSeedArtistsForDay(pool, u, "2026-05-04")
if len(a) != 3 || len(b) != 3 {
t.Fatalf("expected 3 seeds; got %d / %d", len(a), len(b))
}
for i := range a {
if a[i] != b[i] {
t.Fatalf("same day should produce same order; differs at i=%d", i)
}
}
}
func TestPickSeedArtistsForDay_VariesAcrossDays(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
pool := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
{Bytes: [16]byte{30}, Valid: true},
{Bytes: [16]byte{40}, Valid: true},
{Bytes: [16]byte{50}, Valid: true},
}
// Collect the trio (as a sorted byte tuple) across many dates.
// With C(5,3) = 10 possible trios, 30 dates should yield >=2 distinct sets.
seen := map[[3]byte]bool{}
for i := 1; i <= 30; i++ {
got := pickSeedArtistsForDay(pool, u, "2026-05-"+twoDigits(i))
if len(got) != 3 {
t.Fatalf("expected 3 seeds; got %d", len(got))
}
// Sort the three byte values for set-equivalence comparison.
v := [3]byte{got[0].Bytes[0], got[1].Bytes[0], got[2].Bytes[0]}
if v[0] > v[1] {
v[0], v[1] = v[1], v[0]
}
if v[1] > v[2] {
v[1], v[2] = v[2], v[1]
}
if v[0] > v[1] {
v[0], v[1] = v[1], v[0]
}
seen[v] = true
}
if len(seen) < 2 {
t.Errorf("expected >=2 distinct seed trios across 30 days; got %d", len(seen))
}
}
func TestPickSeedArtistsForDay_FewerThanFive(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
pool := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
{Bytes: [16]byte{30}, Valid: true},
}
got := pickSeedArtistsForDay(pool, u, "2026-05-04")
if len(got) != 3 {
t.Errorf("with 3 candidates, expected all 3 returned; got %d", len(got))
}
}
func TestPickSeedArtistsForDay_FewerThanThree(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
pool := []pgtype.UUID{
{Bytes: [16]byte{10}, Valid: true},
{Bytes: [16]byte{20}, Valid: true},
}
got := pickSeedArtistsForDay(pool, u, "2026-05-04")
if len(got) != 2 {
t.Errorf("with 2 candidates, expected 2 returned; got %d", len(got))
}
}
func TestPickSeedArtistsForDay_Empty(t *testing.T) {
u := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
got := pickSeedArtistsForDay(nil, u, "2026-05-04")
if len(got) != 0 {
t.Errorf("empty pool should return empty; got %d", len(got))
}
}
func twoDigits(n int) string {
if n < 10 {
return "0" + string(rune('0'+n))
}
return string(rune('0'+n/10)) + string(rune('0'+n%10))
}