You have written a GS1 parser, and now you need something to test it with. A real product label is the wrong answer twice over: you probably do not have the stock, and somebody else’s batch and serial numbers are not yours to put in a test fixture anyway. So...

A GS1 barcode is not a barcode with a special font. It is an ordinary symbology carrying a string of concatenated data elements, and every one of them starts with an application identifier (AI): two to four digits that say what the value means. That single design decision is what...