Testers don't come in the fancy wrapping or with a cap on them. They are also labeled Tester across them.

The perfume companies provide them to stores at little or no charge, the understanding being that they will not sell the testers or give them away, but use them to help sell the perfume.

That's not to say that they aren't sold or given away but companies will usually limit the number of testers they will give a store so stores like to hang on to them.