feat(api): add conversion helpers for library DTOs

internal/api/convert_test.go

@@ -0,0 +1,75 @@
+package api
+
+import (
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+func TestUUIDToString(t *testing.T) {
+	var u pgtype.UUID
+	if err := u.Scan("00112233-4455-6677-8899-aabbccddeeff"); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	got := uuidToString(u)
+	want := "00112233-4455-6677-8899-aabbccddeeff"
+	if got != want {
+		t.Errorf("uuidToString = %q, want %q", got, want)
+	}
+
+	var zero pgtype.UUID
+	if s := uuidToString(zero); s != "" {
+		t.Errorf("uuidToString(invalid) = %q, want empty", s)
+	}
+}
+
+func TestParseUUID(t *testing.T) {
+	u, ok := parseUUID("00112233-4455-6677-8899-aabbccddeeff")
+	if !ok || !u.Valid {
+		t.Fatalf("parseUUID valid: ok=%v valid=%v", ok, u.Valid)
+	}
+	if _, ok := parseUUID("not-a-uuid"); ok {
+		t.Error("parseUUID accepted garbage")
+	}
+	if _, ok := parseUUID(""); ok {
+		t.Error("parseUUID accepted empty string")
+	}
+}
+
+func TestYearFromDate(t *testing.T) {
+	var d pgtype.Date
+	if y := yearFromDate(d); y != 0 {
+		t.Errorf("yearFromDate(invalid) = %d, want 0", y)
+	}
+}
+
+func TestDurationMsToSec(t *testing.T) {
+	cases := []struct {
+		ms   int32
+		want int
+	}{
+		{0, 0},
+		{500, 1},  // rounds up
+		{499, 0},  // rounds down
+		{1500, 2}, // rounds up
+		{60000, 60},
+	}
+	for _, c := range cases {
+		if got := durationMsToSec(c.ms); got != c.want {
+			t.Errorf("durationMsToSec(%d) = %d, want %d", c.ms, got, c.want)
+		}
+	}
+}
+
+func TestCoverURLAndStreamURL(t *testing.T) {
+	var u pgtype.UUID
+	if err := u.Scan("00112233-4455-6677-8899-aabbccddeeff"); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	if got := coverURL(u); got != "/api/albums/00112233-4455-6677-8899-aabbccddeeff/cover" {
+		t.Errorf("coverURL = %q", got)
+	}
+	if got := streamURL(u); got != "/api/tracks/00112233-4455-6677-8899-aabbccddeeff/stream" {
+		t.Errorf("streamURL = %q", got)
+	}
+}