Create unit tests in ASP.NET core

When I right-click a class in my application code in an ASP.NET MVC 4.6 project then I have this option to create a UNIT Test:

But in my ASP.NET Core (VS2015 Core 1.0.0 Tooling Preview 2) I don't have this option available, when I right-click the class.

I have read that XUnit is now the recommended test framework of choice for ASP.NET Core projects. Is it not possible to use the old good Microsoft Unit Testing Framework?

Are we really forced to use XUnit now?

Update: It looks like there will be a compatible version of the MSTest Framework in the future --> SO Thread. As I don't want to switch to XUnit.