The Titanfall website has details on plans to test Titanfall 2, saying a multiplayer tech test is "around the corner." This will only be on consoles, so Respawn explains why the PC edition is not included. Company cofounder Vince Zampella explains the PC version isn't ready for this yet, but expresses confidence in being ready for launch:

So why not PC?

Two big issues from a development standpoint: hardware variety & “min spec” optimization. We’re still making a lot of tweaks and changes to the renderer, the game, and effects so we haven’t run the game through the hardware compatibility lab yet to detect and handle a large variety of hardware - video cards, CPUs etc. Quite frankly, we aren't ready to deal with that yet, we are still making the game better. We also haven't done enough work to fully support our 'Min Spec' on PC yet. So, currently the PC game isn’t as easy to throw out for testing as the console is, because of the additional variables and configurations that we need to support. Also, because the single player story has some wonderful secrets that we really want to preserve for launch, we also have to worry about leaks. Our wonderfully curious PC players have proven in the past that they will dig out anything they can, and there's a risk that they could spoil some of our single player.

We realize this is a big disappointment for our PC fans, but we feel this allows us to concentrate on the real purpose of the tech test and focus on the server stability and scalability. Rest assured we’re confident in our ability to deliver a great PC experience for launch. We appreciate your understanding, and we look forward to seeing everyone on The Frontier this October.