In context of perfumes, regular retail pack is the complete packaged perfume made for showcase. You will get the sealed bottle in a fancy box packaging.

Testers are the same product, same sealed pack bottle but since they are for purpose of testing ( try before purchasing by a consumer in showroom) , outer box is a ordinary brown / white box. Some products may have ordinary cap also, but every product related details are printed on box similar to a retails pack.

https://www.nextcrush.in/what-are-tester-retail-pack/