Setting up Fitnesse with DotNet Core

I am trying to test out FitNesse with .Net Core, I have created a test fixture and added the nuget package for FitSharp.

using fit;

namespace TestFitnesse
{
    public class MyAcceptanceTests : ColumnFixture
    {
        public string FirstString;
        public string SecondString;
        public string Concatenate()
        {
            return FirstString + " " + SecondString;
        }
    }
}

I have added the following to a FitNesse test page

!contents -R2 -g -p -f -h
!path C:\repos\TestFitnesse\TestFitnesse.dll
!define COMMAND_PATTERN {%m -r fitnesse.fitserver.FitServer %p}
!define TEST_RUNNER {dotnet}
!|TestFitnesse.MyAcceptanceTests      |
|FirstString|SecondString|Concatenate?|
|Hello      |World       |Hello World |
|Bob      |The Builder     |Bob The Builder|

When I save the FitNesse page I get no option to test, so I have set something up wrong somewhere.

On the FitNesse page, select the Tools dropdown and click Properties. Make sure the Test button is selected.