A method for manufacturing a product is provided. The method includes: providing a plurality of components; working on the plurality of components to form the product; and testing the product via a testing method, including: providing first images and second images; assigning the first images by an assigner to a first inspecting unit; determining whether the product corresponding to the first images is OK or not in the first inspecting unit; additionally assigning the second image by the assigner to the first inspecting unit in case no more first image is to be assigned; determining whether the product corresponding to the second image is OK or not in the second inspecting unit or additionally in the first inspecting unit; and sending a message of OK by the assigner for outputting the product that is determined OK.