You can download right now on japanese Eshop ( but you can change your region after that )

The Splatoon 2 Global Test Fire is available for download right now on the Nintendo Switch eShop! The dates & times it can be played are below:

March 24:
12-12:59pm PT
8-8:59pm PT

March 25:
4-4:59am PT
12-12:59pm PT
8-8:59pm PT

March 26:
4-4:59am PT

Here are things we should see professional channels like Digital Foundry pay attention to:

1. Battery life when playing online
2. Overall usability of online
3. How many "mlgnosc0pers" there are

really hoping nintendo benefits from this

Can't you do that with Bomberman online multiplayer? 

bomberman has been having issues. this will also allow us to stress test the servers

Nice, would love to try it out but don't have a Switch so that will have to wait

Wait how is #3 relevant? xD

What I'm interested in learning are the gameplay mechanics, namely the rollers new vertical flick and how much OHKO range it has compared to the horizontal flick.

while its understandable that the Testfire is meant to be a stress test, its a bit dulled by the fact that a lot of people who would want to participate in the testfire dont have a Switch yet

Is this going to be available in NA / EU eshops?

yes it is now

http://www.neogaf.com/forum/showthread.php?t=1352443

Too bad I'll most likely going to play only one of those.