We have received many requests to support .NET Core and are very eager to do so.

One of the main obstacles has been that our test projects depend on some libraries that don't support .NET Core.

NSubstitute has been slow to support .NET Core, and it is unclear when or if they will.

While the official Moq branch does not yet support .NET Core, the ASP.NET team has been using a fork of Moq that does.

Given the importance of the ASP.NET project, we believe that this fork will soon be integrated with the official branch, and we believe that in the short and long term we will be better off depending on Moq than on NSubstitute.