The first few questions are where you'll find your answers.
As for TESTERS... They are basically a store made version of a scent with no aesthetic qualities outside the original bottle. Some come without a cap and they sport a plain white box. They are mean to be used in stores a way to test a fragrance without buying it, like a free trial. The scent itself is they exact same, the bottle as well, so don't be nervous about buying a tester instead of the visually pleasant version. You save a few bucks with the testers as well.