What Ive found in europe the past 10 years is local sellers are often selling cheaper products. Some are good, some dosed low. Some are plain shit. Its like the go to bargain outlet to purchase a resale pack and its hit or miss. One vial can be good, others are not.
Like Kad said, most wont fake test. but the higher cost raws are what will be faked. I just heard from a guy in Europe market offering extremely cheap products and doing the math, its in no way a real product unfortunately. They would be making zero profit or losing money at the rate they are selling for.