Unit-test of ASP.NET Core controller

I've created an ASP.NET Core app and I also added a .NET Core library for testing the controllers but when I try to add the reference to the ASP.NET Core project Visual Studio shows the following error message:

App.Web has target frameworks that are incompatible with targets in current framework. App.Tests: .NETStandard,Version=1.6 App.Web: .NETCoreApp,Version=v1.0

Currently the App.Tests project targets:

"frameworks": {
  "netstandard1.6": {
    "imports": "dnxcore50"
  }
}

And the App.Web project targets the following:

"frameworks": {
  "netcoreapp1.0": {
    "imports": [
      "dotnet5.6",
      "portable-net45+win8"
    ]
  }
},

Changing netcoreapp1.0 to netstandard1.6 doesn't help, neither changing the imports, because NuGet fails for App.Web.

What frameworks should I target on boths projects so that one can reference the other?

Thanks