}); err != nil {
		t.Errorf("failed to replace item content, got error: %v", err)
	}

	if count := tx.Model(&item).Association("Contents").Count(); count != 3 {
		t.Errorf("expected %d contents, got %d", 3, count)
	}

	var contents []ItemContent
	if err := tx.Find(&contents).Error; err != nil {
		t.Errorf("failed to find contents, got error: %v", err)
	}
	if len(contents) != 3 {