Unit Testing ASP .NET 5 MVC 6

I was trying to find way to unit test my ASP.NET 5 MVC 6 project in VS 2015 I found it very hard to do it "old way" (nunit or similar approach).

Then I found this article http://ift.tt/1EpFsFT

In point 10 they say that xUnit.Net is now way to go. Do you know any step by step guide how to do it?

Things I could found on internet are very confusing.