chore: establish local platform baseline

internal/media/service_test.go

@@ -0,0 +1,53 @@
+package media
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestNormalizeManifestIsDeterministic(t *testing.T) {
+	first := []SegmentDeclaration{
+		{Track: "far", SequenceNo: 2, Codec: "wav_pcm_s16le", ContentType: "audio/wav", DurationMS: 5000, ExpectedSize: 1200, ExpectedDigest: strings.Repeat("b", 64)},
+		{Track: "near", SequenceNo: 1, Codec: "wav_pcm_s16le", ContentType: "audio/wav", DurationMS: 5000, ExpectedSize: 2400, ExpectedDigest: strings.Repeat("a", 64)},
+	}
+	second := []SegmentDeclaration{first[1], first[0]}
+	digestA, normalized, total, err := normalizeManifest(first)
+	if err != nil {
+		t.Fatal(err)
+	}
+	digestB, _, _, err := normalizeManifest(second)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if digestA != digestB {
+		t.Fatalf("manifest digest changed with input order: %s != %s", digestA, digestB)
+	}
+	if normalized[0].Track != "far" || normalized[1].Track != "near" {
+		t.Fatalf("manifest was not sorted: %#v", normalized)
+	}
+	if total != 3600 {
+		t.Fatalf("total = %d, want 3600", total)
+	}
+}
+
+func TestNormalizeManifestRejectsInvalidDeclarations(t *testing.T) {
+	base := SegmentDeclaration{Track: "near", SequenceNo: 1, Codec: "wav_pcm_s16le", ContentType: "audio/wav", DurationMS: 5000, ExpectedSize: 1200, ExpectedDigest: strings.Repeat("a", 64)}
+	tests := []struct {
+		name  string
+		items []SegmentDeclaration
+	}{
+		{name: "empty"},
+		{name: "duplicate", items: []SegmentDeclaration{base, base}},
+		{name: "track", items: []SegmentDeclaration{func() SegmentDeclaration { item := base; item.Track = "mixed"; return item }()}},
+		{name: "codec content type mismatch", items: []SegmentDeclaration{func() SegmentDeclaration { item := base; item.ContentType = "audio/opus"; return item }()}},
+		{name: "digest", items: []SegmentDeclaration{func() SegmentDeclaration { item := base; item.ExpectedDigest = "no"; return item }()}},
+		{name: "size", items: []SegmentDeclaration{func() SegmentDeclaration { item := base; item.ExpectedSize = 0; return item }()}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if _, _, _, err := normalizeManifest(tt.items); err == nil {
+				t.Fatal("normalizeManifest accepted invalid input")
+			}
+		})
+	}
+}