fix(backend): serialize SQLite test connections and await async normalize

backend/chat/src/handlers/handlers_test.go

@@ -103,6 +103,13 @@ func setupTestDeps(t *testing.T) (*Dependencies, *gorm.DB, *auth.SessionStore) {
 	if err != nil {
 		t.Fatalf("failed to open test DB: %v", err)
 	}
+	// A single connection keeps the in-memory SQLite database shared across
+	// goroutines (each :memory: connection would otherwise be a separate DB).
+	sqlDB, err := gormDB.DB()
+	if err != nil {
+		t.Fatalf("failed to get sql.DB: %v", err)
+	}
+	sqlDB.SetMaxOpenConns(1)
 	gormDB.AutoMigrate(&db.Message{}, &db.ModerationLog{}, &db.Media{}, &db.ScheduleOverride{}, &db.User{})
 	mr := newMockRedis()
 	sessionStore := auth.NewSessionStore()
@@ -1361,4 +1368,30 @@ func TestHandleAdminMediaByID_Normalize(t *testing.T) {
 	if w.Code != http.StatusAccepted {
 		t.Errorf("status = %d, want 202", w.Code)
 	}
+
+	// Wait for the asynchronous normalization goroutine to finish before
+	// t.Cleanup restores media.NormalizeVideo, avoiding a data race on the
+	// package-level mock variable.
+	var updated db.Media
+	deadline := time.Now().Add(5 * time.Second)
+	for {
+		gormDB.First(&updated, 1)
+		if updated.Status != media.StatusNormalizing {
+			break
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("normalization did not complete within 5s")
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	if updated.Status != media.StatusReady {
+		t.Errorf("Status = %q, want ready", updated.Status)
+	}
+	if updated.DurationSeconds != 90 {
+		t.Errorf("DurationSeconds = %d, want 90", updated.DurationSeconds)
+	}
+	if !strings.HasSuffix(updated.Path, ".normalized.mp4") {
+		t.Errorf("Path = %q, want .normalized.mp4 suffix", updated.Path)
+	}
 }