test: keep the encoding tests fast under the race detector

The morning animation test draws one loop and is skipped under -race,
where it took minutes. The order of frames drawn at once is checked on a
tiny scene instead, which the race detector does see.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: amtiYo

internal/anim/anim_test.go

@@ -2,6 +2,8 @@
 package anim
 
 import (
+	"bytes"
+	"context"
 	"image"
 	"image/color"
 	"math"
@@ -213,3 +215,31 @@ func BenchmarkMorningFrame(b *testing.B) {
 		s.Draw(c, 3+float64(i%240)/FPS)
 	}
 }
+
+// counter paints frame i in grey level i, so the raw stream shows the order.
+type counter struct{}
+
+func (counter) Size() (int, int)  { return 8, 4 }
+func (counter) Duration() float64 { return 2 }
+func (counter) Draw(c *Canvas, t float64) {
+	v := float32(math.Round(t*FPS)) / 255
+	c.Fill(RGB{v, v, v})
+}
+
+// Frames drawn at once are written in order, every one of them.
+func TestFramesComeInOrder(t *testing.T) {
+	var out bytes.Buffer
+	st, err := frames(context.Background(), counter{}, 7, &out)
+	if err != nil {
+		t.Fatal(err)
+	}
+	const size = 3 * 8 * 4
+	if st.Frames != 60 || out.Len() != 60*size {
+		t.Fatalf("%d frames, %d bytes", st.Frames, out.Len())
+	}
+	for i := range 60 {
+		if got := out.Bytes()[i*size]; int(got) != i {
+			t.Fatalf("frame %d holds frame %d", i, got)
+		}
+	}
+}

internal/schedule/animate_test.go

@@ -109,6 +109,9 @@ func TestMorningAnimationOnceADay(t *testing.T) {
 	if err != nil {
 		t.Skip("no ffmpeg")
 	}
+	if raceEnabled {
+		t.Skip("encoding under the race detector takes minutes")
+	}
 	dir := t.TempDir()
 	img := image.NewRGBA(image.Rect(0, 0, 128, 64))
 	for y := range 64 {
@@ -125,11 +128,13 @@ func TestMorningAnimationOnceADay(t *testing.T) {
 	}
 	f.Close()
 
+	// One animator for the day, as in the service: it draws once.
+	animator := &Animator{FFmpeg: ffmpeg}
+	rd := db.Round{Date: round.NewDate(2026, 11, 2), DayNo: 4, PlaceID: 1}
 	send := func(kind string, refuse bool, chats ...int64) *animTG {
 		tgc := &animTG{refuse: refuse}
 		s, _ := resultSender(nil, panoStore{kind: kind})
-		s.TG, s.ImagesDir, s.Anim = tgc, dir, &Animator{FFmpeg: ffmpeg}
-		rd := db.Round{Date: round.NewDate(2026, 11, 2), DayNo: 4, PlaceID: 1}
+		s.TG, s.ImagesDir, s.Anim = tgc, dir, animator
 		for _, c := range chats {
 			if _, err := s.sendPost(context.Background(), c, rd, "caption", nil); err != nil {
 				t.Fatal(err)
@@ -141,10 +146,14 @@ func TestMorningAnimationOnceADay(t *testing.T) {
 	if len(tgc.animations) != 2 || len(tgc.animations[0].MP4) == 0 || tgc.animations[1].FileID != "A1" || len(tgc.photos) != 0 {
 		t.Fatalf("animations %d, photos %d", len(tgc.animations), len(tgc.photos))
 	}
+	// Telegram refusing the file sends the photo, and the other chats go
+	// straight to the photo.
+	if tgc := send("panorama", true, 3, 4); len(tgc.photos) != 2 {
+		t.Fatalf("refused: photos %d", len(tgc.photos))
+	}
+	// A photo place never tries.
+	rd.Date = rd.Date.AddDays(1)
 	if tgc := send("photo", false, 1); len(tgc.animations) != 0 || len(tgc.photos) != 1 {
 		t.Fatalf("photo place: animations %d, photos %d", len(tgc.animations), len(tgc.photos))
 	}
-	if tgc := send("panorama", true, 1, 2); len(tgc.photos) != 2 {
-		t.Fatalf("refused: photos %d", len(tgc.photos))
-	}
 }

internal/schedule/norace_test.go

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build !race
+
+package schedule
+
+const raceEnabled = false

internal/schedule/race_test.go

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build race
+
+package schedule
+
+// raceEnabled skips the tests that encode a whole animation: under the race
+// detector one takes minutes.
+const raceEnabled = true