There are a ton of posts about this topic and I guess there is good reason. 10 yrs ago almost all reps leaked and if you even went outside in the humidity in the summertime they would fog up and in about a month or two the movement would freeze up from all the rust and corrosion. For this reason everyone says "get it tested" Now I am not going to sit here and tell you not to get it tested, but I will say that rep makers have gotten a lot better at making both movements and making watches that don't leak. I have tested a lot of rep Dive watches in the past 5 yrs and it is pretty rare that I get one to leak. It can happen, but it is certainly the exception, rather than a common thing. I would still suggest to get it tested as it is only a few dollars and it will save a lot of trouble & money if you happen to get unlucky enough to get one from the factory that leaks.
There is another option and that is to make one yourself. It is cheap and is a fun little project..........
Here is a link to a thread where one member shows how to make a waterproof tester out of a nalgene bottle:
https://forum.replica-watch.info/forum/modification-repairs/28489-build-a-pressure-tester-for-30-dollars
I snooped around and improved the idea a lot, IMHO. Anyway, around page 8 on that thread I got involved and showed how you could do it for slightly more, but much more safely and to a much higher pressure. Here is my post:
https://forum.replica-watch.info/for...16#post4794116
btw
I have gone swimming, diving off a 3m platform, wakesurfing, wakeboarding, waterskiing, snorkeling, tubing etc with my 2018 smp and never gave it a second thought. I think the likelihood of something else happening to it (like a springbar failing) is probably 100x more likely than it leaking.